Fisheries and Aquatic Sciences

Graduate Student Symposium

PROGRAM

February 22, 2019

Austin Cary Forest, Florida

GRADUATE STUDENT SYMPOSIUM

ORGANIZING COMMITTEE

Allison Durland Donahou (lead), Scott Borsum, Derek Chamberlin, Kristen Dahl,

Michael Espriella, Nick Fisch, Jeff Greenspan, and Justin Lewis

Faculty

Coordinators

Dr. Rob Ahrens, Dr. Shirley Baker, Dr. Edward

Camp, Dr. Kai Lorenzen

Feb 22, Fisheries and Aquatic Sciences Graduate Student Symposium Agenda

8:00-­­9:00 Registration Session I Moderator: Erin Bohaboy 9:00-­9:10 Welcome and Announcements 9:10-­9:25 Evaluating the use of composition data within fisheries assessment and

its effect on management Nick Fisch (Rob Ahrens) 9:25-­9:30 Evaluating environmental drivers that influence recruitment

of spotted seatrout in Cedar Key, FL Samara Nehemiah (Mike Allen) 9:30-­9:45 A study proposal to evaluate non-lethal ageing methods for Red

Snapper Lutjanus campechanus Jessica Carroll (Deb Murie) 9:45--9:50 A novel approach to estimate age and examine aging error in exploited

reef fish populations via aspartic acid racemization in eye lenses Derek Chamberlin (Will Patterson) 9:50—9:55 Factors influencing year class strength and spatial and temporal

occupancy of hogfish (Lachnolaimus maximus) in open estuarine systems of the Big Bend region, Florida

Johnny Polasik (Mike Allen) 9:55-­10:00 Density-dependent condition and growth of invasive lionfish in the

northern Gulf of Mexico Kristen Dahl (Will Patterson) 10:00-­10:05 Population declines in northern Gulf of Mexico lionfish following

emergence of an ulcerative skin disease

Holden Harris (Will Patterson and Mike Allen) 10:05-­10:10 Professional Ted Talk 1 - Ed Camp 10:10-­10:35 Coffee Break Session II Moderator: Scott Alford 10:35--10:50 Occupational displacement of people who fish commercially: The case

of the Florida gill net ban May Lehmensiek (Kai Lorenzen) 10:50-­10:55 Using ordination techniques to help understand community structure Jeff Greenspan (Jeff Hill) 10:55-­11:10 Changes in reef fish community structure following the Deepwater

Horizon Oil Spill Justin Lewis (Will Patterson) 11:10­­11:15 Exploring population-level impacts of sea turtle vessel strikes along the

northwest coast of Florida Trenton Aguilar (Mike Allen) 11:15-­11:20 Effects of river discharge on seagrass and fish communities in the

Steinhatchee and Econfina Estuaries, Florida Stephanie Winn (Mike Allen) 11:20­­11:25 Examining the differing feeding preferences of herbivorous fish and

sea urchins Lindsay Spiers (Tom Frazer) 11:25­­11:40 The effects of nutrient reduction on the population of largemouth bass

Micropterus salmoides in Lake Alice, Gainesville, Florida Marina Schwartz (Dan Canfield)

11:40-­11:45 Potential impact of non-native pike killifish on juvenile common snook  

Geoffrey Smith (Deb Murie) 11:45-­12:00 Live fast, die young: Decapoda with shorter lives seem more prone to

increased parasite diversity Elizabeth Duermit-Moreau (Don Behringer) 12:00-­12:05 Professional Ted Talk 2 - Shirley Baker 12:05­­1:00 Lunch Session III Moderator: Scott Borsum

1:00-­1:05 Evaluating efficacy of several disinfectants on hatchability in Almaco Jack Seriola rivoliana eggs Genevieve Patrick (Roy Yanong)

1:05-­1:20 Domestication induced differences in reproductive output and growth of the African Clawed Frog Xenopus laevis

Allison Durland Donahou (Jeff Hill) 1:20-­1:35 Describing digestive system ontogeny in Gymnocorymbus ternetzi:

Progress towards early weening Taylor Lipscomb (Matthew Dimaggio) 1:35—1:40 Evaluating larviculture protocols for pelagic spawning marine

ornamental Grace Sowaske (Matthew Dimaggio)

1:40-­1:55 Establishment of assay methodologies of hemocytes in responses to the environmental stresses of the hard clam Mercenaria mercenaria

Zeng Yangqing (Huiping Yang)

1:55­­2:00 Total lipid profiles in the common microalgae used

for shellfish aquaculture

Marlyn Kallau (Huiping Yang) 2:00-­2:15 Effects of nonnative eurasian watermilfoil, Myriophyllum spicatum, on

nekton habitat quality in a Louisiana oligohaline estuary Scott Alford (Charles Martin) 2:15-­2:20 Plan to determine submerged aquatic vegetation preferences of fishes

in Lake Apopka Audrey Looby (Charles Martin) 2:20—2:25 Quantifying fish habitat impairment in Iowa’s lakes and reservoirs Erin Haws (Charles Cichra) - (Recorded) 2:25-2:30 Professional Ted Talk 3 - Zach Siders 2:30 – 2:50 Coffee Break Session IV Moderator: Audrey Looby 2:55-­ 3:00 Professional Ted Talk 4 - Vincent Lecours 3:00-­ 3:05 Enhancing restoration of an iconic Florida gulf coast habitat and

species: Seagrass and bay scallops Shelby Thomas (Josh Patterson) 3:05-­3:20 Marine sportfish response to large scale restoration in Tampa Bay Kailee Schulz (Quenton Tuckett) 3:20­­3:25 Assessment of restoration efforts in a coastal preserve, Tampa Bay,

Florida Amanda Croteau (Charles Cichra) 3:25--3:30 Lone Cabbage oyster reef restoration: Effects of oyster restoration on

nekton assemblages in the Big Bend region of Florida Chelsea Conley (Michael Allen)

3:30--3:35 Modeling Oyster Reef Ecosystem Services to Inform Policy

Charles Wallace (Ed Camp) 3:35--3:40 Using high-resolution unmanned aerial system imagery to monitor

intertidal oyster reefs along Florida’s Big Bend coastline Michael Espriella (Vincent Lecours) 3:40-­­3:45 An ecophysiological approach to modeling hard

clam (Mercenaria mercenaria) mortality events Ken Black (Shirley Baker) 3:45-­­4:00 Break 4:00-­­5:00 Poster Session 5:00---5:30 Poster and Presentation Awards 5:30 Cleanup, Appetizers, and Beverages

Poster Session:

Management implications of descender device usage in the Gulf of Mexico red snapper recreational fishery Erin Bohaboy [William Patterson] Native herbivores improve rearing methods for sexually produced staghorn coral in land-based nurseries Joseph Henry [Josh Patterson] Risk-based approach to evaluate alligator gar Atractosteus spatula aquaculture in Florida Lauren Lapham [Jeff Hill] Distribution of oyster predators across environmental gradients in Cedar Key, FL Gabrielle Love [Ed Camp, Shirley Baked] Mitigating conspecific aggression in larval Pictichromis paccagnellae, using substrate Benjamin Lovewell [Courtney Ohs] Symbiont uptake in the upside-down jellyfish. How do different strains of Symbiodinium impact Cassiopea xamachana polyps? Casandra Newkirk [Tom Frazer] Reproductive biology of female Atlantic yellowfin tuna from the Gulf of Mexico and U.S. Atlantic coast Ashley Pacicco [Deb Murie] Developing intensive aquaculture of the long-spined sea urchin Diadema antillarum as a tool for coral reef restoration Aaron Pilnick [Aaron Pilnick] Pioneer snook: Tracking the genetic effects of settling territory in the Big Bend region of Florida Emma Pistole [Mike Allen]

Effects of 17α-methyltestosterone immersion and feeding on masculinization of the dwarf gourami and rosy barb Shane Ramee [Matt DiMaggio]

Common bottlenose dolphin (Tursiops truncatus) distribution and abundance in the brackish environment of Sabine Lake, northwestern Gulf of Mexico Errol Ronje [Juliane Struve]

The effects of predatory drills on Florida bay scallop growth, mortality, and parasite load Abigail Scro [Donald Behringer]

The relationship between freshwater discharge and salinity on estuarine fish communities in Cedar Key Dylan Sinnickson [David Chagaris]

ORAL PRESENTATION ABSTRACTS

Effects of nonnative eurasian watermilfoil, Myriophyllum spicatum, on nekton habitat quality in a

Louisiana oligohaline estuary

Scott B. Alford1 and Lawrence P. Rozas2 1 University of Florida/Institute of Food and Agricultural Sciences Nature Coast Biological Station; 552 1st St., Cedar Key,

FL 32625, USA 2 NOAA/National Marine Fisheries Service/SEFSC, Estuarine Habitats and Coastal Fisheries Center; 646 Cajundome Blvd.,

Lafayette, LA 70506, USA

Corresponding author: Scott Alford, scott.alford@ufl.edu

Submerged aquatic vegetation (SAV) provides critical habitat for estuarine nekton in the Gulf of Mexico,

but habitat quality of SAV beds may change when nonnative species, such as Eurasian watermilfoil

(Myriophyllum spicatum), become established. We compared the habitat value

of Myriophyllum with another common native SAV (Ruppia maritima) by using field collections to

document shifts in nekton community structure and a field experiment to compare growth rates

of commercially-important juvenile white shrimp (Litopenaeus setiferus). Similar communities were

collected from both SAV species, though nekton abundance scaled with SAV biomass.

The habitat quality provided by Myriophyllum for white shrimp appeared to meet or exceed that

of Ruppia, with densities and growth rates of shrimp in Myriophyllum (2.2 ± 0.47 m-2, 1.0 ± 0.07 mm TL

d-1, 25.7 ± 2.98 mg d-1) higher than in Ruppia (1.0 ± 0.36 m-2, 0.6 ± 0.09 mm TL d-1, 11.6 ± 2.04 mg d-

1). Though differences were detected between SAV species, other factors, such as hypoxia and

interspecific competition, likely contributed to the differences we documented between these habitat

types in shrimp densities and growth. Our study provides an example of a nonnative habitat-forming

species providing a viable alternative to native habitat. This result contradicts the paradigm of negative

effects associated with nonnative species following their introduction into an ecosystem.

Exploring population-level impacts of sea turtle vessel strikes along the northwest coast of Florida

Trenton A. Aguilar Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL.

Corresponding author: Trenton Aguilar, trenton.aguilar@ufl.edu

Globally, all species of sea turtles are considered endangered or threatened, largely due to anthropogenic

threats. An often-overlooked hazard is vessel strikes, which result in live and dead strandings of many, if

not all, sea turtle species. In the US Virgin Islands during 1982-1997, it is estimated that vessel strikes

caused 34% of all reported strandings. In Hawaii, regardless of their low frequency of occurrence, vessel

strikes have the highest mortality per-event of the threats observed in the region. This low frequency has

led vessel strikes to be neglected in the field of sea turtle conservation. However, with some turtle

populations beginning to rebound, and an increase of anthropogenic use of sea turtle habitat, is this an

oversight in conservation concerns? Florida waters contain five of the seven sea turtle species (Green

turtles - Chelonia mydas, Loggerhead turtles - Caretta caretta, Leatherback turtles - Dermochelys

coriacea, Hawksbill turtles - Eretmochelys imbricata, and Kemp’s Ridley turtles - Lepidochelys kempii),

including three species that have extensive nesting beaches along Florida’s coasts (Greens, Loggerheads,

and Leatherbacks). With Florida’s large recreational and commercial boating presence along its coasts,

which coincide with many of the present species migratory, foraging, and nesting areas, a study describing

sea turtle avoidance maneuvers and reaction times to vessels is a necessary step in lowering anthropogenic

mortality rates. I will discuss a future study addressing this issue, which will

include a comprehensive model that describes and compares a wide range of mortality sources along the

Northwest Coast of Florida.

An ecophysiological approach to modeling hard clam (Mercenaria mercenaria) mortality events 

Kenneth Black1 and Shirley Baker1 1 Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL

Corresponding author: Kenneth Black, kwblack@ufl.edu

We modified an ecophysiological model of hard clam (Mercenaria mercenaria) growth to assess the

dynamics of a mass mortality event at the Dog Island Lease Area (DLA) off Cedar Key, FL that occurred

in the summer of 2003. This event resulted in significant losses of the farmed clam population within the

DLA, estimated at >50% of that season’s crop. Specifically, we modeled the impact of four important

water quality parameters (temperature, salinity, turbidity, and chlorophyll concentration) that are known

to moderate either respiration rates or feeding rates. We ran simulations using environmental data from

2003 and compared it to actual growth and mortality data from the same period. Our analysis suggests

that freshwater pulses originating from the Suwannee River resulted in transient periods of low salinity

(<10 ppt) which combined with simultaneous high water temperatures (>30oC) and that the detrimental

impacts of the two factors likely combined to cause the clam deaths.

Evaluation of dorsal fin rays and spines as a non-lethal ageing method for Goliath

Grouper Epinephelus itajara

Jessica Carroll1,3, Angela Collins2, Robert Ellis3 and Debra Murie1 1 SFRC-Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL. 2 Florida Sea Grant, University of Florida IFAS Extension, Palmetto, FL. 3 Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL.

Corresponding author: Jessica Carroll, Jessica.Carroll@myfwc.com

Atlantic Goliath Grouper Epinephelus itajara is the largest grouper in the western North Atlantic, and it

exhibits life history characteristics (e.g. slow growing, long-lived, late maturity) that make it particularly

susceptible to fishing pressure. In 1990 a harvest moratorium for Goliath Grouper in US waters was

enacted, which created a data-poor environment from which to assess the stock status. Biological data,

particularly fish ages, needed to estimate population parameters for stock assessments. Otoliths, the

typical structure processed for age determination, are usually collected as part of fisheries monitoring, but

are not available from Goliath Grouper because of their protected status. Structures that can be acquired

via non-lethal sampling such as dorsal fin rays or spines, may provide a viable alternative for

ageing. The Florida Fish and Wildlife Conservation Commission (FWC) has been collecting incidental

Goliath Grouper samples from cold kill, red tide and other mortality events since

2006. Corresponding otolith, dorsal fin ray and dorsal spine samples were compared to determine the

accuracy of these alternative ageing structures. The fish in this dataset range in age from 1–35 years (as

determined by otoliths), and in size from 112–2244 mm TL. Preliminary results from these comparisons

and subsequent fisheries management implications will be discussed. This research will inform biological

sampling methodology for Goliath Grouper ageing structures and has the ability to directly impact the

stock assessment, and potentially, the determination of recovery of the species.

A novel approach to estimate age and examine aging error in exploited reef fish populations via

aspartic acid racemization in eye lenses

Derek Chamberlin1, William F. Patterson III1, Virginia Shervette2, and Robert Ahrens1

1 University of Florida, School of Forest Resources and Conservation, Gainesville, FL 2 University of South Carolina Aiken, Department of Biology and Geology, Aiken, SC

Corresponding author: Derek Chamberlin, derek.chamberlin@ufl.edu

Age is the fundamental parameter of population ecology. Population models rely heavily on accurate

estimates of vital rates, such as growth and mortality, which in turn rely on accurate age estimates. Age is

estimated by counting the number of opaque or translucent zones, depending on the structure, but these

counts must be validated as having been formed annually to estimate age in years. Amino acid

racemization (AAR) in eye lenses has the potential to provide an independent estimate of fish age. Amino

acids exist in two optical isomers, levorotatory (L) and dextrorotatory (D) enantiomers. Living organisms

produce only the L enantiomer. However, in tissues that have no metabolic activity, such as eye lenses,

the L enantiomer converts to the D enantiomer, and vice versa, through a process called racemization. The

rate of racemization is temperature dependent, with higher rates of racemization at higher temperatures.

This approach has not been applied to poikilotherms, such as fish. However, it is unknown exactly what

effect temperature has on AAR rates and whether that can be accounted for in estimating age. The

objectives of this study are to 1) test the efficacy of estimating fish age with amino acid racemization

under controlled conditions, 2) validate age estimates and growth parameters in wild caught temperate

(greater temperature variability) and tropical (lower temperature variability) reef fishes via AAR, and 3)

conduct population assessment simulations to test the implication of aging error on the resistance and

resiliency of populations to perturbations.

Lone Cabbage oyster reef restoration: Effects of oyster restoration on nekton assemblages in the

Big Bend region of Florida

Chelsea Conley1,2, Caleb Purtlebaugh2, Michael Allen1, and Charles Martin1 1 Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, Nature Coast Biological Station, University of

Florida, Cedar Key, FL. 2 Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Senator George Kirkpatrick Field

Lab, Cedar Key, FL.

Corresponding author: Chelsea Conley, chelsea.conley@ufl.edu

Oyster Reefs provide an important habitat for many invertebrate and fish species, coastal protection from

erosion, water quality enhancement, and serve as an economically beneficial fishery. They are also one of

the most threatened marine ecosystems in the world, with an estimated 85% loss of oyster reefs world-

wide. The Lone Cabbage Reef, located in Suwannee Sound off Florida’s Big Bend coast, has been funded

by NFWF for a large-scale restoration project, beginning Fall 2018. This project will restore 3km of reef

using limestone and shell to provide a permanent structure to allow oyster spat to settle, and maintain a

structure during periods of oyster population die-off. Although the oyster restoration project is directed

towards restoring the oyster populations that are essential to the oyster fishery, it may also have ecosystem

wide effects on the estuarine fish and invertebrate communities, regardless of the success of the oysters

themselves. Enhanced abundances of juvenile fish species have been recorded for restored oyster reefs in

mud-flats, and these areas can provide prey items and refuge for juvenile fish and invertebrates. Florida

Fish and Wildlife Research Institute’s Fisheries Independent Monitoring (FIM) program has collected

long-term stratified random sampling data in the Cedar Key and Suwannee Sound areas for over 20 years.

The objectives of this study are to analyze historic FIM data in the Lone Cabbage Reef area and increase

spatial resolution along Lone Cabbage Reef using FIM procedures to assess fish and select invertebrate

assemblages before and after the oyster restoration project.

Assessment of restoration efforts in a coastal preserve, Tampa Bay, Florida

Amanda C. Croteau and Charles Cichra Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL.

Corresponding author: Amanda Croteau, acroteau@ufl.edu

Florida’s coastal habitats have been severely impacted by development. In the past 100 years, Tampa Bay

has lost >44% of its mangrove and salt marsh habitat. Robinson Preserve is a 197-hectare preserve, located

on the southern shore of Tampa Bay. Originally a coastal wetland, the property was ditched, drained, and

used for agriculture. Tidal flow was restored in 2006. While upland and salt marsh vegetation were

planted, aquatic flora and fauna were left to colonize from neighboring populations. Robinson Preserve

was sampled quarterly from 2007-2013 to evaluate the success of restoration activities and changes in

water quality. Different species colonized the preserve at different rates based on life-history

characteristics. Within the first year following tidal reconnection, 18 fish and 14 invertebrate species had

been collected. Although the rate of colonization slowed, at least one new species was documented during

each subsequent sampling event. After 7 years of colonization, 98 fish and 105 invertebrate species have

been observed. A number of species are ubiquitous, others are seasonal, and some appear to fluctuate

based on the presence/absence of specific habitat types, such as macroalgae and seagrass. Numerous

commercially or recreationally important species utilize the preserve for juvenile refuge and/or adult

foraging (e.g., snook, red drum, and mullet).

Density-dependent condition and growth of invasive lionfish in the northern Gulf of Mexico 

Kristen A. Dahl1,2, William F. Patterson III2, and Morgan A. Edwards2 1 University of Florida, School of Natural Resources and Environment, Gainesville, FL 32611 2 University of Florida, School of Forest Resources and Conservation, Gainesville, FL 32611

Corresponding author: Kristen Dahl, kristendahl@ufl.edu

Invasive red lionfish (Pterois volitans) were sampled in the northern Gulf of Mexico (nGOM) to examine

effects of sex, habitat (natural versus artificial reefs), and population density on condition (i.e., mass

relative to total length) and growth. Lionfish density was estimated with a remotely operated vehicle

during 2010-2017 at a series of nGOM natural (n = 16) and artificial (n = 22) reefs, and individual lionfish

(n = 3,296) were sampled via spearfishing at other reefs in the same system between 2013 and 2017. Fish

were weighed, measured to total length (TL), and their ages estimated by counting opaque zones in

otoliths. Mean lionfish TL increased across the time period, while density increased through 2015 and

then stabilized or slightly declined. Lionfish density at artificial reefs was two orders of magnitude greater

than at natural reefs throughout the time period. Fish condition was lower on artificial reefs across all

years, and lower on natural reefs during 2015-17 versus 2013-14. Age estimates ranged from 0.2 to 7.7

years, corresponding to birth years between 2008 and 2016. There were significant differences in growth

and size-at-age between sexes and habitats, with males attaining larger size-at-age than females and fish

growing faster at natural reefs. There were also significant declines in mean size-at-age and condition as

a function of fish density. Overall, these results indicate condition and size-at-age displayed density-

dependent effects that were likely due to inter- and intra-specific competition, which has important

implications for invasive lionfish carrying capacity in the nGOM.

Live fast, die young: Decapoda with shorter lives seem more prone to increased parasite diversity

Elizabeth Duermit-Moreau1, Donald C. Behringer1,2, and Jamie Bojko1 1 Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, University of Florida 2 Emerging Pathogens Institute, University of Florida

Corresponding author: Elizabeth Duermit-Moreau, duermite@ufl.edu

Parasitism is not evenly distributed among animal taxa. This over-dispersion of parasitism means that

coevolution with parasites may be of greater importance to the biology and ecology of some hosts. Host

characteristics correlating with parasite species richness (PSR) can provide insight into links between

animal behavior, habitat-based exposure, diversity, and infection risk. Crustaceans comprise lucrative

fisheries and aquaculture but reports from the scientific literature suggest a disparity in the PSR between

various crustacean taxa. Thus, further understanding the role of parasites in crustacean evolution is of

importance to global food security. Using 162 decapod crustaceans, we conducted a meta-analysis

associating life history and ecological traits with PSR. These crustaceans harbored 339 parasite species,

resulting in an analysis of 642 host-parasite relationships. We controlled for how well studied each species

is by considering the number of publications per species and whether the relationship is found in the wild

or exclusively in aquaculture. Shrimp, which are significantly shorter-lived, are infected by significantly

more viruses per host species and a greater proportion of obligate parasites than longer-lived

lobsters. These data suggest that parasite diversity is negatively correlated with longevity, meaning that

longer lived species may have more adequate innate and behavioral immune capabilities. Shorter-lived

decapods appear susceptible to a greater diversity of parasites, which has implications for conservation

and food security.

Domestication induced differences in reproductive output and growth of the African Clawed

Frog Xenopus laevis

Allison Durland Donahou1,2, Quenton M. Tuckett2, Joseph Laich2, Jeffrey E. Hill2 1 School of Natural Resources and Environment, University of Florida 2 Fisheries and Aquatic Sciences, Tropical Aquaculture Laboratory, University of Florida, Ruskin, FL

Corresponding author: Allison Durland Donahou, adurland@ufl.edu

Domestication can alter life history traits due to the relaxation of environmental pressures, such as food

scarcity and predation. The goals of culturing an organism for profit can lead to altered life history traits

– selection for the largest, most fecund, fastest growing individuals can alter reproductive output and

growth. Changes in life history traits due to domestication were analyzed in a model organism: the African

Clawed Frog Xenopus laevis. Domesticated broodstock of X. laevis were obtained from a local Florida

breeder and wild broodstock were collected directly from the native range in South Africa. Reproductive

output and growth were analyzed to determine if there are differences in life history traits between

domesticated and wild X. laevis. The number and size of eggs were recorded and tadpoles were used to

examine growth in domesticated and wild X. laevis. Preliminary results indicated that there was no

difference in relative fecundity between domesticated and wild X. laevis. However, the average egg size

was significantly larger for wild than for domesticated X. laevis. This indicates that the reproductive output

by number of eggs of domesticated and wild X. laevis may be the same, but larger egg size indicates a

competitive advantage of wild offspring survival in the natural environment. Wild tadpoles grew faster

than domesticated tadpoles under the same conditions. Domestication does not seem to have affected the

reproductive output of X. laevis, but faster growth combined with potentially higher egg quality indicates

that domestication has reduced the fitness of X. laevis tadpoles.

Using high-resolution unmanned aerial system imagery to monitor intertidal oyster reefs along

Florida’s Big Bend coastline

Michael C. Espriella, and Vincent Lecours Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, University of Florida, Gainesville, FL

Corresponding author: Michael Espriella, michaelespriella@ufl.edu

In Florida, eastern oyster (Crassostrea virginica) reefs are important economically and provide a range of

essential ecosystem services (e.g., pollutant filtration, shoreline erosion control). However, these

services and fisheries are threatened, as there has been an estimated 66% decline in eastern oyster reef

area along Florida’s northwestern coast since 1982. This decline along a vastly undeveloped coastline

presents an opportunity to study the spatial and temporal dynamics of a system without excessive human-

induced change. However, sampling oyster reefs is often costly in terms of financial, human, and time

resources. Here we propose the use of unmanned aerial system (UAS) imagery off the coast of Cedar Key,

FL, as an alternative to address this issue. UAS provide a relatively inexpensive method to collect data on

intertidal reefs at a very high spatial resolution. A quadcopter UAS will collect imagery that will be

mosaicked and used to produce a digital terrain model. Geographic Object-Based Image Analysis

(GEOBIA) will be used extract live oyster counts and densities from the ortho-mosaic. GEOBIA segments

images by regrouping pixels into distinct objects that can then be classified according to similarities in

attributes. Each object will be summarized based on its spectral, topographical and structural components,

which are then used to classify them into one of four classes: live oyster, dead oyster, surrounding reef

elements, and shadow. The potential of UAS imagery to produce accurate live oyster counts presents an

expedient and inexpensive monitoring technique that has the capability of assessing the health of reefs

elsewhere.

Evaluating the use of composition data within fisheries assessment and its effect on management

Nicholas Fisch, Robert Ahrens, and Ed Camp Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences,

University of Florida.

Corresponding author: Nick Fisch, nfisch@ufl.edu

Within a fisheries stock assessments, age and size composition data have traditionally been represented

using the multinomial likelihood. The multinomial likelihood is an imperfect model for these data as

it cannot account for the correlations and overdispersion that exist in the data. Not accounting for these

phenomena within an assessment can affect point estimates and precision of quantities important to

fisheries ecology and management. Methods to remedy this have included down-weighting composition

data within assessment and using alternative likelihoods to the multinomial. Down-weighting composition

data in stock assessment is laborious and does not ultimately account for the correlation in the residuals,

and alternative likelihoods for composition data have not all been evaluated using stock

assessment simulation. To more fully understand this problem, and ultimately propose ‘best practice’

solutions, a spatially explicit age structured stochastic simulation model - able to

mimic the correlation structure observed in composition data – will be developed. Assessment

models will be fit to simulated data to test the performance of various likelihood structures. In addition,

the impact of data sampling regimes on the statistical nature of the composition data will be explored to

determine if port sampling programs need to be evaluated. ‘Best practices’ determined from the simulation

modeling will then be applied to a suite of federally managed stocks to determine the overall effect on

management reference points. Finally, the multinomial and other composition likelihoods will be

explored within a management strategy evaluation context to determine their effect on sustainability of

fish stocks given management strategies.

Using ordination techniques to help understand community structure

Jeffrey B. Greenspan Fisheries and Aquatic Sciences, Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, University of

Florida, Gainesville FL.

Corresponding author: Jeff Greenspan, jeffgreenspan@ufl.edu

Your field work is complete. Maybe you’re studying one species in a community, or maybe you are

looking at an entire community of species. How do you tease out the effects that one species has on

another, or on that community? Ordination analysis is used to explore data across multiple axes and

reveals similarities and dissimilarities, so it is typically used for exploring your data as opposed to testing

specific hypotheses. Several types of ordination analysis exist, so we’ll discuss when to use each one.

Then we’ll explore how I used non-metric multidimensional scaling (NMDS) to reveal whether Blue

Tilapia, an invasive species in Florida, has negative impacts on the native community.

Population declines in northern Gulf of Mexico lionfish following emergence of an ulcerative skin

disease

Holden Harris1, Alexander Q. Fogg2, Micheal S. Allen3,4, Robert N. M Ahrens3, and William F.

Patterson III3 1 School of Natural Resources and Environment, Institute of Food and Agriculture Sciences,103 Black Hall, Gainesville, FL

32611. 2 Okaloosa County Board of County Commissioners, Emerald Coast Convention and Visitors Bureau, Fort Walton Beach, FL 3 Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, Institute of Food and Agriculture Sciences,

University of Florida, Gainesville, FL 32653. 4 Nature Coast Biological Station, Institute of Food and Agriculture Sciences, University of Florida, Cedar Key, FL 32625.

Corresponding author: Holden Harris, holdenharris@ufl.edu

Indo-Pacific lionfish in the western Atlantic Ocean is the most successful marine fish invasion. High

densities of lionfish have had region-wide deleterious effects on reef fish communities and ecosystem

processes. However, these high population densities, combined with low genetic diversity, could also

make lionfish more susceptible to disease. Lionfish presenting ulcerative skin ulcers were first reported

from northern Gulf of Mexico (nGOM) artificial reefs in Aug 2017. We examined nGOM lionfish

populations using surveys conducted before-and-after disease emergence on high-density artificial reef

sites with and without lionfish removals. In addition, we assessed changes catch per unit of effort (CPUE)

from annual lionfish harvests, relative fish condition for ulcerated versus non-ulcerated fish by sex, and

lionfish population size structure for lionfish caught in 2014–2018. Lionfish densities decreased by 88%

from Oct 2016 to Oct 2018, while densities on sites where lionfish had previously been removed were

higher. Lionfish CPUE during annual tournaments decreased by 51% between 2017 and 2018. Relative

condition was significantly lower for ulcerated female lionfish, but not males. Finally, we observed a large

decline in small (<180 mm total length), presumably age-0, lionfish during May–Aug 2018. Following

the irruption of lionfish on nGOM reefs since 2010, natural mechanisms appear to have caused recent,

dramatic declines. Lower-conditioned females, and the absence of juveniles the following year, suggest

recruitment failure occurred during spring and summer 2018. Greater declines at higher-density sites

suggest density-dependent disease transmission may have occurred. Increases in lionfish density, and the

presence of juveniles on study reefs by fall 2018, indicate observed population declines may not persist

into the future.

Quantifying fish habitat impairment in Iowa’s lakes and reservoirs

Erin M. Haws Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL.

Corresponding author: Erin Haws, erin.haws@ufl.edu

Freshwater ecosystems provide a diverse supply of resources to fauna and flora living within, to

surrounding ecosystems, and human economies. As bodies of water evolve, so do the methods used to

protect and restore them.  Over the past decade, emphasis on sustaining freshwater ecosystems has led to

an expansion in the development of protective policies and restoration programs aiming to improve

aquatic habitat.  A recurring challenge to fish habitat restoration lies in defining impairment factors, their

scale and the rate at which they are occurring in a system.  Comprehensive assessments are therefore

needed to identify impairments, prioritize waterbodies in need of restoration, and provide improved

methods to measure local fish habitat using feasible metrics. This study provides a look into lake and

reservoir fish habitat in Iowa based on a survey reporting on all publicly owned lakes recognized by the

Iowa Department of Natural Resources (IDNR).  The survey asked DNR Fisheries Biologists to report the

degree of impairment of a set of variables for each individual waterbody in their management area. 

Multivariate factors were classified using the methods of Krogman and Miranda (2016), characterizing

twelve broad constructs of fish habitat impairment.  Study objectives include describing fish habitat

impairment trends and identifying differences across lake type, watershed location, and status in the Lake

Restoration Program.  Future research plans aim to quantify relationships between fish habitat impairment

constructs and measured water quality, physical, and biological parameters within existing datasets to

evaluate the resources available to adequately measure fish habitat.

Total lipid profiles in the common microalgae used for shellfish aquaculture

Marlyn Kallau1 and Huiping Yang1 1 Fisheries and Aquatic Science, School of Forest Resource and Conservation, Institute of Food and Agricultural Science,

University of Florida, Gainesville, FL.

Corresponding author: Marlyn Kallau, msuzannakallau@ufl.edu

Phytoplankton microalgae are the food source for shellfish bivalves. The commonly used microalgae in

shellfish aquaculture include 1) Haptophytes (Isochrysis aff. galbana; both clone T-Iso and C-Iso), 2)

diatoms from Ochrophytes (Thalassiosira pseudonana, Thalassiosira weissflogii, Chaetoceros calcitrans,

Chaetoceros gracilis), and 3) green algae from Chlorophyte (Tetraselmis suecica), Ochrophyte

(Nannochloropsis oculata) and Chrysophyte (Pavlova lutherii). To provide the optimum nutritional needs

for larvae growth and survival and broodstock sex maturity for shellfish seed production, the feeding

microalgae need to have a required biochemical composition (lipid, protein and glycogen) and suitable

cell sizes and density. There is a limited resource corresponding to lipid accumulation and utilization for

shellfish aquaculture. To enhance understanding of nutrient utilization, investigation of lipid accumulation

and characteristic in microalgae as feed is needed. The goal of this study is to evaluate total lipid profiles

in commonly used microalgae in shellfish aquaculture. The objectives will be to: 1) establish methodology

for fast and accurate total lipid measurement using flow cytometry; 2) evaluate the total lipid change at

different culture day in the commonly used microalgae species, and 3) assemble the lipid measurements

with microalgal age, sizes, and cell characterization to establish the lipid profile for feeding formula. Lipid

is one major energy source for shellfish growth and survival. This study will lay a foundation for further

investigation the roles of nutrients from different species in shellfish to enhance the larval survival and

broodstock condition for seed production.

Occupational displacement of people who fish commercially: The case of the Florida gill net ban

May Lehmensiek School of Natural Resources and the Environment, University of Florida, Gainesville, FL.

Corresponding author: May Lehmensiek, mayl@ufl.edu

Many small-scale fishing operations are under significant pressure and undergoing large changes due to

fishing regulations, market forces, industrialization, and environmental changes. These changes can lead

to the occupational displacement of people who fish commercially. Work is an important part of most

people’s lives and holds meaning beyond the earning of wages and the securing of a livelihood. For people

who fish commercially, identity, attachment, social ties, traditions, and social norms are deeply entwined

with the fishing occupation, both on the individual level as well as for communities and the loss of the

occupation can be very stressful and deeply disruptive. With my research, I am trying to understand how

commercial fishers experience occupational displacement so that better strategies can be developed to

avoid displacement and mitigate negative outcomes. I am using the case study of the Florida Gill Net Ban

and have conducted qualitative interviews with people who commercially gill net fished before the net

ban. Pre-liminary results indicate that these fishers perceive that occupational displacement had a large

disruptive effect on many aspects of their lives. I am using the Impoverishment Risks and Recovery (IRR)

model to organize findings and to suggest that, for commercial fishers, the experience of occupational

displacement can be similar to that of communities that are physically displaced against their will.

Changes in reef fish community structure following the Deepwater Horizon Oil Spill

Justin P. Lewis1, Joseph H. Tarnecki1, Steven B. Garner1, David D. Chagaris1,2, and William F. Patterson

III1 1 University of Florida, Fisheries and Aquatic Sciences, Gainesville, Florida 32608, USA 2 University of Florida, Nature Coast Biological Station, Cedar Key, FL 32625, USA

Corresponding author: Justin Lewis, justin.lewis@ufl.edu

Large-scale disturbances in marine ecosystems can alter food web structure with both acute and long-

term consequences. Here, we report the results of a time-series that captured the effects of the Deepwater

Horizon oil spill (DWH) on fish community and trophic structure on northern Gulf of Mexico reefs.

Immediately following DWH, we observed a significant change in community structure and significantly

lower species richness. Declines in species richness did not persist, and long-term changes in community

structure, though significant, appear within the range of natural variation. However, initial changes in

community structure driven by widespread declines across a range of trophic guilds were not followed by

equally ubiquitous recoveries. Densities of small demersal invertivores, small demersal browsers,

generalist carnivores, and piscivores remained low with little indication of recovery up to 7 years

following the DWH. Although these declines occurred prior to the arrival of the invasive lionfish

(Pterois sp.), the lack of recovery among small demersal browsers and invertivores suggests lionfish

predation may be affecting recovery. However, the cause of persistently low densities of generalist

carnivores and piscivores, such as snappers, groupers, and jacks, likely reflects a combination of

factors and warrants further exploration considering the ecological and economic importance of these

fishes.

Describing digestive system ontogeny in Gymnocorymbus ternetzi: Progress towards early weening

Taylor N. Lipscomb, Matthew A. DiMaggio Fisheries and Aquatic Sciences, Tropical Aquaculture Laboratory, Institute of Food and Agriculture Science, University of

Florida, Ruskin, FL.

Corresponding author: Taylor Lipscomb, tlipscomb@ufl.edu

Among the many challenges encountered during the production of freshwater ornamental fish, larval

nutrition persists as a bottleneck. Limited survival, abbreviated growth and apparent dependence on live

feeds are all characteristic of this life stage in many ornamental fishes. A significant amount of the

ornamental larvae reared intensively upon first feeding are fed newly-hatched Artemia franciscana (brine

shrimp) nauplii, which is costly and has inconsistent availability. Members of the family Characidae, and

particularly tetras, appear to require live feeds for larval propagation. However, research into early

digestive physiology of ornamental Characids is limited. The current study employed a series of

experiments with Black Tetra Gymnocorymbus ternetzi to evaluate replacing Artemia with commercially

available micro-particulate diets (MD) during larval culture. Three MDs were compared to Artemia (n =

6) for the first 10 days of exogenous feeding, with growth and survival being primary indicators of success.

After limited success was observed with the MDs relative to Artemia (6.9 ± 2.1% and 20.8 ±

7.3% survival, respectively), additional larvae fed exclusively Artemia were evaluated to 24 days post

hatch to describe digestive system ontogeny. Activity of three critical digestive enzymes (trypsin, pepsin,

and bile salt dependent lipase) as well as histological development of gastrointestinal structures were

evaluated. Characterization of larval digestive ontogeny revealed a protracted altricial stage, with the

appearance of gastric glands and concurrent pepsin activity occurring only after 22 dph.

Future investigations will use this information to develop larval weening protocols to

optimize production of the Black Tetra.

Plan to determine submerged aquatic vegetation preferences of fishes in Lake Apopka

Audrey Looby1,2, Laura K. Reynolds3, Carrie Reinhardt Adams4, and Charles W. Martin2 1Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL. 2UF/IFAS Nature Coast Biological Station, University of Florida, Cedar Key, FL. 3Soil and Water Science, University of Florida, Gainesville, FL. 4Environmental Horticulture, University of Florida, Gainesville FL.

Corresponding author: Audrey Looby, alooby@ufl.edu

Until the 1940’s, Lake Apopka was known for clear water and dense submerged aquatic vegetation

(SAV) that supported a productive recreational fishery. After 1940, the lake was impacted by number

of anthropogenic disturbances that reduced SAV and fish abundance. Despite numerous restoration

efforts that have had some positive impacts, Lake Apopka is still plagued by poor water clarity,

unconsolidated sediments, and a loss of macrophytes. Using an adaptive restoration strategy, we are

currently working to restore SAV genetic and species diversity in Lake Apopka. Here we present future

work that will be directed at assessing fish community structure in restored SAV, as well as determining

fish preferences for different SAV species, characteristics, and diversity. The first component of our

research will consist of comparative field sampling of fish populations with fyke nets, baited lines, and

minnow traps. The second component will consist of paired choice experiments in a controlled tank

environment. The data collected during this project will help inform our decision making and drive

management decisions regarding the most effective means to restore Lake Apopka.

Evaluating environmental drivers that influence recruitment of spotted seatrout in Cedar Key,

FL

Samara Nehemiah1 and Mike Allen1 1 Fisheries and Aquatic Sciences, IFAS Nature Coast Biological Station, University of Florida, Cedar Key, FL

Corresponding author: Samara Nehemiah, s.nehemiah@ufl.edu

Spotted Seatrout, (Cynoscion nebulosus), are a highly desirable sport fish in Florida. Currently, Spotted

Seatrout are managed by the Florida Fish and Wildlife Conservation Commission (FWC) in four

management zones. FWC’s Fisheries-Independent Monitoring Program (FIM) uses stratified random

sampling to monitor the abundance and population of sport fish, including Spotted Seatrout, in estuaries

across Florida. Relative Indices of Abundance (IOAs) are created for young-of-the-year Spotted Seatrout

to evaluate recruitment in six estuaries including Cedar Key. Year class strength is important for

understanding population health and implementing management decisions but IOAs for Spotted Seatrout

have yet to be validated. Various environmental pressures such as weather events can influence

recruitment of Spotted Seatrout. In this proposed study we hope to validate IOAs calculated by FIM

by using catch curve residuals. Catch curves take the natural log of the catch at age data and create a

regression against age. Residuals above the regression will indicate strong year classes and residuals

below will indicate weak year classes of Spotted Seatrout in Cedar Key. We will then plot various

environmental factors against the catch curve residuals. We plan to evaluate the effect of salinity and

discharge, storms, seagrass, and mangroves on year class strength. Fish carcasses will be obtained from

charter captains based in Cedar Key and undersized fish will be targeted under permit using hook-and-

line.

Evaluating efficacy of several disinfectants on hatchability in Almaco Jack Seriola rivoliana eggs

Genevieve Patrick1, Andrea M. Tarnecki2, Nicole Rhody3, Ryan Schloesser3, and Kevan Main3 1Tropical Aquaculture Lab, University of Florida, Ruskin, FL 33570 2Marine Immunology Program, Mote Marine Laboratory, Sarasota, FL 34240 3Marine and Freshwater Fish Program, Mote Marine Laboratory, Sarasota, FL 34240

Corresponding author: Genevieve Patrick, gpatrick@ufl.edu

Seriola rivoliana is considered an excellent candidate for aquaculture due to its fast growth rate and high

market value; however, there is no published information available on the Gulf of Mexico stocks. While S.

rivoliana have adapted well to captivity, survival can be improved. A wide range of variables cause larval

mortalities but high bacterial loads in rearing tanks are often correlated with these losses. The aim of this

study was to investigate the effect of egg disinfection on bacterial load and hatch rate of S.

rivoliana. We chose 3 disinfectants FDA-approved for use in various stages of fish aquaculture.

Concentrations and contact times were chosen based on current use in aquaculture: 35% Perox-aid (300

ppm, 10 min), Parasite-S (100 ppm and 200 ppm, 1 h each), and Peroxy-serve MPS (15 ppm, 1

min). Following disinfection, eggs were incubated to determine percent hatch rate. Additional eggs were

homogenized and plated on thiosulfate citrate bile salts sucrose agar (TCBS,

total Vibrios counts). 35% Perox-aid and Parasite-S at 100 ppm had significantly higher hatch rates than

the control. All treatments significantly decreased total Vibrio counts as compared to the control.

Factors influencing year class strength and spatial and temporal occupancy

of hogfish (Lachnolaimus maximus) in open estuarine systems of the Big Bend region, Florida

John R. Polasik1, Michael Allen1, Charles Martin1, and Caleb Purtlebaugh2 1 Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, Nature Coast Biological Station, University of

Florida, Cedar Key, FL. 2 Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Senator George Kirkpatrick Field

Lab, Cedar Key, FL

Corresponding author: John Polasik, john.polasik@myfwc.com

Estuarine seagrass beds are known as essential habitat for ontogenetic species during the critically

important juvenile stage of life. The Big Bend region of Florida contains one of the largest

contiguous examples of such seagrass habitats in the eastern Gulf of Mexico. Natural physical, biotic,

and anthropogenic factors such as pH. habitat contour, seagrass coverage, river discharge, and

temperature can influence species spatial and temporal preferences within these areas. This project will

utilize long term (2008-2018) trawl data to characterize year class strength and the spatial and temporal

patterns of habitat selection of juvenile Hogfish (Lachnolaimus maximus) in three eastern Gulf of Mexico river

influenced open estuary systems in Florida: St. Mark’s, Econfina, and Steinhatchee. Data will be analyzed

for each system to see trends in year class strength, relative abundance, and spatial and temporal

preferences in relation to many biotic and abiotic factors. A comparative analysis will be conducted to

assess if the same factors influence hogfish recruitment and preferences in the same manner in the

different study locations.

Exploring fisheries aspects of large-scale habitat restoration in Tampa Bay

Kailee Schulz1, Phil Stevens2, Jeffrey Hill1,4, Alexis Trotter2, Jared Ritch2, Josh

Patterson1,3, Quenton Tuckett1,4 1 Fisheries and Aquatic Sciences, University of Florida, School of Forest Resources and Conservation, Apollo Beach, FL

33572 2 Florida Fish and Wildlife Research Institute, St. Petersburg, FL 3 Center for Conservation, The Florida Aquarium, Apollo Beach, FL 33572 4 Tropical Aquaculture Laboratory, Fisheries and Aquatic Sciences, Institute of Food and Agricultural Sciences, University of

Florida, Ruskin, FL

Corresponding author: Kailee Schulz, ka.schulz@ufl.edu

Tampa Bay is a coastal restoration success story. In recent decades numerous entities have worked to

restore historically impacted wetlands. This has recreated hundreds of acres of estuarine habitat lost to

disturbance. It is assumed that fish community structure and commercially/recreationally important

sportfish will benefit from these major restoration activities. Specifically, these restored areas should offer

nursery habitat for sportfish such as common snook (Centropomus undecimalis) and red drum (Sciaenops

ocellatus). Also, the areas should provide habitat that allows for a diverse prey base, within the range of

expectations for coastal wetlands, that can provide for community resilience and a consistent source of

prey production. However, few data exist to support these assumptions. Quarterly randomized sampling

with 9.1-m and 40-m seines was used to characterize the fish communities at three restored, three

impacted, and three natural sites on the eastern shore of Tampa Bay. Routine habitat data were collected

for each net pull. A subset of captured juvenile common snook was retained for laboratory processing

(body condition, growth, and daily otolith aging). Preliminary results indicate juvenile common snook

have faster growth at restored sites compared to natural or impacted locations. Also, shoreline restoration

led to increased spatial heterogeneity, providing a mosaic of vegetation and habitat characteristics, leading

to increased fish diversity. These results may be used to guide resource managers on the effectiveness of

specific habitat restoration practices and tailor restoration design to specific fisheries goals.

The effects of nutrient reduction on the population of largemouth bass Micropterus salmoides in

Lake Alice, Gainesville, Florida

Marina Schwartz1 1 Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, University of Florida, Gainesville, FL.

Corresponding author: Marina Schwartz, mevanskeene@ufl.edu

Phosphorus and nitrogen are widely considered the limiting nutrients in lake systems. Prior to 1994, Lake

Alice, Gainesville, Florida received treated effluent from a wastewater treatment facility. In October 1994,

a new wastewater reclamation plant was opened, and the treated effluent was rerouted, no longer

contributing excess nutrients to the lake. Lake Alice is home to an unfished population of Largemouth

Bass Micropterus salmoides. This study examines how the Largemouth Bass population has responded to

the reduction in nutrients due to the removal of treated wastewater effluent. Water chemistry and

Largemouth Bass Data collected by UF’s Introduction to Fisheries science class was analyzed for the

years surrounding the removal of effluent and examined for relationships between effluent presence,

absence, and bass population parameters. It seems that nutrient reduction in lakes located in naturally

phosphorus rich areas of the state will not change the trophic state of a lake. However, if a lake is managed

specifically for fishing, based on this study, and previous findings in Florida lakes, nutrient inputs will

help increase the size and condition of large trophy Bass in a fishery. If a lake is managed for aesthetics

or recreation, however, approaches other than nutrient reduction will yield better results, specifically in

naturally eutrophic Florida lakes.

Potential impact of non-native pike killifish on juvenile common snook  

Geoffrey Smith1, and Debra Murie1 1 University of Florida, School of Forest Resources and Conservation, Gainesville, FL 32611

Corresponding author: Geoffrey Smith, geoffreyhsmith@ufl.edu

Pike Killifish is an established non-native fish species in Florida that was first documented in south Florida

in 1957 and secondarily in Tampa Bay tributaries in 1994. Decreases in small-bodied fish abundances

have been linked to the introduction of Pike Killifish in both of these regions. Increases in the range and

abundance of Pike Killifish in the Tampa Bay area and overlap in habitat usage has led to concerns about

potential predation on, and competition with, early-juvenile Common Snook (≤100 mm SL). Several lines

of evidence point to minimal or no impacts of Pike Killifish on early-juvenile Snook in Tampa Bay

tributaries. Predation trials indicate that Pike Killifish are capable of consuming juvenile Snook up to 48

mm SL, but no Snook remains have been found in the diet analysis of Pike Killifish. There is a small

degree of diet overlap between these species and declines in the abundance of some prey groups has been

detected in locations where Pike Killifish and Snook co-occur. However, diet overlap of early-

juvenile Snook from locations with and without Pike Killifish co-occurring remains high and there is no

indication of reduced condition or growth of early-juvenile Snook in the presence of Pike

Killifish. Differences in microhabitat use may partially explain the lack of apparent competition between

these two species.

Examining the differing feeding preferences of herbivorous fish and sea urchins

Lindsay Spiers1 and Tom Frazer1 1 Fisheries and Aquatic Sciences Program, School of Forest Resources and Conservation, Institute of Food and Agriculture

Science, University of Florida, Gainesville, FL

Corresponding author: Lindsay Spiers, lspiers@ufl.edu

There are many different factors affecting the health of coral reefs worldwide. In the Caribbean, the loss

of two key herbivores, fish and the long-spined sea urchin Diadema antillarum, led to dramatic

increases in macroalgae. These increases have been linked to significant decreases in coral cover and

overall coral reef health. In some locations, herbivorous fish and D. antillarum populations have begun

to recover. As herbivore abundance increases, reductions in macroalgal cover and abundance are

anticipated. Harder to predict and perhaps more important are herbivore effects on macroalgal assemblage

structure. Knowing feeding preferences of these different herbivores is important because different

macroalgae have different effects on coral. To address these questions, different feeding assays were

conducted using either herbivorous fish or D. antillarum and nine different algae and one seagrass

commonly found around Little Cayman. These different species were either palatable

or employed different types of defenses against herbivory (chemical, structural, or both). D.

antillarum feeding assays were conducted in the laboratory. In these assays, each urchin was presented

with either one experimental species or four species. Fish feeding assays were conducted in the field using

existing fish communities at both a shallow (<3 meters) and a deep (~18 meters) site. Fish were most

deterred by chemically defended species while D. antillarum were deterred by species with structural

defenses. These different feeding preferences may indicate the importance of having both fish and D.

antillarum present for a controlled macroalgal community and reduction in one major stressor affecting

Caribbean coral reefs.

Evaluating larviculture protocols for pelagic spawning marine ornamental species

Grace Sowaske1 and Matt DiMaggio1 1 Fisheries and Aquatic Sciences, Tropical Aquaculture Lab, Institute of Food and Agricultural Science, University of Florida,

Ruskin, Fl.

Corresponding author: Grace Sowaske, gracesowaske@ufl.edu

The marine aquarium hobby has grown considerably in recent decades to become a multi-billion-dollar

industry. Only a handful (<10%) of commercially available marine species are cultured while the rest

are wild-caught. The global industry is working to provide more cultured stock in order

to reduce harvest pressures on imperiled ecosystems. Species that are demersal spawners dominate the

aquaculture market due to the availability of established rearing protocols, increased parental care and

relatively high larval survival. Pelagic spawning species usually provide no parental care and the newly

hatched larvae have a small mouth gape that limits their diet to copepod nauplii and other small

zooplankton or phytoplankton. These challenges need to be addressed for pelagic species production to

become commercially viable. The pelagic spawning species such as the Blue Tang

(Paracanthurus hepatus), Melanurus Wrasse (Halichoeres melanurus), and Yellow Wrasse

(Halichoeres chrysus) are species of particular interest because of their popularity in the trade and lack

of established rearing methods. My proposed research will focus on manipulation

of various environmental and nutritional parameters during early larviculture for these three species.

These investigations will better define protocols which yield increased survival and growth and can then

be transferred to commercial producers. Parameters of interest include live algal species and density

for greenwater larviculture, larval stocking density, tank size, and nauplii species and density will

be employed during early culture stages. Results from these investigations will help to shape future

production protocols.

Enhancing restoration of an iconic Florida gulf coast habitat and species: Seagrass and bay

scallops

Shelby Thomas1 1 Fisheries and Aquatic Sciences, Institute of Food and Agricultural Sciences, University of Florida, Apollo Beach, FL

Corresponding author: Shelby Thomas, shelby.thomas.21@ufl.edu

Seagrasses provide food and critical habitat for a variety of marine species. They are a vital part of the

marine ecosystem and help maintain water quality, stabilize the sea bottom, and support local

economies. Bay scallops are obligate residents of seagrass beds and an indicator species of coastal water

quality. In addition to their economic importance derived from recreational fisheries, scalloping and the

scallops themselves are a beloved symbol of summertime leisure for many

Floridians. Unfortunately, various anthropogenic factors have resulted in progressive declines in water

quality and seagrass beds. Rural communities along central Florida’s Gulf Coast are dependent on healthy

costal resources, like seagrasses, for activities such as fishing, scalloping, and wildlife

viewing. Unfortunately, these activities can also damage these resources. Careless or improper boating

can cause propeller scarring, which damages seagrass habitat. We will study seagrass propeller scar and

bay scallop restoration efforts in Citrus County and Tampa Bay, respectively. The aim is to generate

information that will dovetail to create a framework for improving these two restoration practices, which

have important ecological linkages. Seagrass restoration studies will employ robust monitoring of restored

scars with environmental metagenomics to improve understanding of the biological transition from dry,

“sterile” encapsulated sediment to marine benthos permeated with rhizomes. Density-dependence in bay

scallop larvae released for restoration will be tested experimentally. Further, previously developed

microsatellite markers will be used across four hatchery spawns to measure genetic diversity of released

animals and potentially identify scallops found post-restoration. The project goal is a holistic approach to

restoration, providing a unique opportunity to improve outcomes for one of Florida’s most iconic

ecosystems.

Modeling Oyster Reef Ecosystem Services to Inform Policy

Charles Wallace1

1University of Florida, School of Forest Resources and Conservation, Gainesville, FL 32611

Corresponding author: Charles Wallace, cwallace1@ufl.edu

Oysters provide coastal socioecological systems with many ecosystem services including water

filtration, increased finfish and crustacean production, and reducing wave energy and preventing shore

erosion the continued provision of these services is imperiled with ongoing declines in oyster reef

systems. This has motivated both oyster restoration actions and also consideration of alternative oyster

fishery management regulations. Making good decisions about alternative management or restoration

decisions is challenging, especially because it is difficult to predict the net benefits and consequences of

these decisions on ecosystem services. I want to predict the ecosystem service value of the Lone

Cabbage Reef restoration under alternative management strategies for wild oyster harvest. Once the

values of the different management strategies have been extracted, I want to understand how different

management options are viewed by different stakeholder groups, including oyster fishers and non-fisher

coastal residents. I anticipate this information in concert with the ecosystem service predictions can lead

to effective policy being enacted and may also increase stakeholder investment in the management

process.

Presentation type: Speed Talk

Effects of river discharge on seagrass and fish communities in the Steinhatchee and Econfina

Estuaries, Florida

Stephanie G. Winn1,2, Michael Allen1, Charles Martin1, and Caleb Purtlebaugh2 1 Fisheries and Aquatic Sciences, Institute of Food and Agriculture Science, Nature Coast Biological Station, University of

Florida, Cedar Key, FL. 2 Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Senator George Kirkpatrick Field

Lab, Cedar Key, FL

Corresponding author: Stephanie Winn, stephanie.winn@myfwc.com

Seagrass communities provide essential habitat for commercially and recreationally important fish and

invertebrate species. Approximately 85% of the recreational and commercial fish species in Florida

spend a portion of their life in estuarine and nearshore seagrass habitats, and the Big Bend region of

Florida contains one of the largest expanses of continuous seagrass habitats in the eastern Gulf of

Mexico. Riverine input influences estuarine community structure in these areas, including seagrass and

nekton productivity, coverage, and abundance. Substantial reductions in the freshwater discharge of

coastal rivers, which have been documented in this region, can have long-term negative effects on estuary

ecosystems and seagrass community composition. Both natural and anthropogenic factors such as

drought, drawdown, or damming can alter the quantity of freshwater reaching these coastal areas. This

project will utilize 11 years of existing trawl data collected by the Florida Fish and Wildlife Conservation

Commissions (FWC), Fisheries Independent Monitoring Program (FIM). In addition to FIM trawl data,

this project will also utilize river discharge data from the United States Geological Survey (USGS). Data

will be analyzed for each system to evaluate trends in fish assemblages and relative abundance in relation

to river discharge. The influence of changes in river discharge and associated environmental

conditions have on fish communities in seagrass beds will be assessed for the Steinhatchee and Econfina

estuaries. A comparative analysis will be conducted to assess if river discharge has similar effects on

these two systems.

Establishment of assay methodologies of hemocytes in responses to the environmental stresses of

the hard clam Mercenaria mercenaria

Yangqing Zeng, Zhe Zhang, Huiping Yang Fisheries and Aquatic Sciences, School of Forest Conservation and Resources, University of Florida, Gainesville, FL 32653

Corresponding author: Yangqing Zeng, zengyangqing@ufl.edu

The hard clam, Mercenaria mercenaria, is an important aquaculture species with a $65 million production

along the U.S. east coast. Challenges for hard clam aquaculture include environmental stresses, such as

the hot summers in Florida and harmful algal bloom. Hard clams are poikilothermic with open circulatory

system, hemocytes can function as multiple-purpose defense cells through immune responses to protect

host against natural environmental stresses, diseases, and toxins. The goal of this study was to establish

standardized methodologies for immunoassays of hemocytes in hard clams by use of a flow cytometer.

The objectives were to1) determine the hemocyte morphology through microscopic observation and cell

count of different types using flow cytometer; 2) develop methodologies for hemocyte immunoassays

including cell viability, apoptosis, phagocytosis, and lysosome; 3) determine expression of heat shock

protein 70 (HSP70) using flow cytometer, and 4) develop non-lethal methodologies for hemocyte

collection for these immunoassays. Market-sized hard clams at 12-14 month-old were used in this study.

Hemocytes will be collected from the adduct muscle by using a 21-g needle attached to 3-ml syringe after

dissection or through hinge ligaments. Hemocyte morphology was observed after H&E staining. Similar

to that in most shellfish bivalves, three types of hemocytes were identified in the hard clams. The research

is currently ongoing; more data is in process of collection. It is expected that the methodologies to be

established in current study will be applied to further investigation.

POSTER ABSTRACTS

Management implications of descender device usage in the Gulf of Mexico red snapper

recreational fishery

Erin C. Bohaboy1, Shannon L. Cass-Calay2, Robert Ahrens1, and William F. Patterson III1 1 University of Florida, Fisheries and Aquatic Sciences, Gainesville, FL. 2 NOAA Southeast Fisheries Science Center, Miami, FL.

Corresponding author: Erin Bohaboy, erin.bohaboy@ufl.edu

The ability of descender devices to reduce red snapper release mortality was assessed using three-

dimensional acoustic telemetry and the resulting changes in mortality were incorporated into stock

recovery simulations to evaluate stock trajectories and management reference points. Acoustic telemetry

arrays provide geoposition estimates for tagged fish, giving unique insight into their fine-

scale movement, behavior, habitat preferences, and survival. We deployed a large acoustic telemetry

array south of Pensacola, Florida at 30 m and then at 55 m depths. Red snapper (n = 141) were captured

at artificial reefs within the arrays, tagged externally with acoustic transmitter tags, released either at the

surface or at depth with a weighted return-to-depth (descender) device, and then tracked three-

dimensionally for up to a year. Red snapper released at the surface exhibited higher acute and delayed

(>2 days) mortality than descender-released fish. Predation by highly mobile predators, which has not

been reliably observed in previous discard mortality studies, accounted for the majority of acute (<48

hours) mortality. Stock Synthesis model simulations indicated that decreasing discard mortality (as would

occur with widespread descender device usage among recreational fishers) and implementing harvest slots

(regulations requiring fish above a certain size be released) could increase recreational catch, harvest, and

fish size while allowing for longer recreational fishing seasons. These results suggest descender devices

may be an effective tool to reduce discard mortality in red snapper and could enable the use of harvest slot

regulations as a viable management tool for the Gulf of Mexico red snapper recreational fishery.

Native herbivores improve rearing methods for sexually produced staghorn coral in land-based

nurseries

Joseph Henry, Keri O’Neil, and Joshua Patterson Fisheries and Aquatic Sciences, The Florida Aquarium at Apollo Beach, Apollo Beach, FL.

Corresponding author: Joseph Henry, Henry8404@ufl.edu

The coral Acropora cervicornis, commonly known as staghorn coral, was once spatially dominant but is

now highly threatened throughout its native range. In recent years, The Florida Aquarium has made great

advancements in ex-situ sexual propagation of Caribbean corals. Thus, improving grow-out strategies for

sexually produced recruits in land-based nurseries is becoming increasingly important to the active

restoration of this species and maintenance of genetic diversity in out planted A. cervicornis. Given limited

time and resources, it is important to identify the most effective techniques when rearing A. cervicornis

ex-situ. Growing corals with herbivorous snails is one strategy for algae control and reducing the amount

of time spent on system maintenance. For this study, we utilized staghorn coral recruits collected from the

July 2018 coral spawn and raised them from settlement with similar densities of juvenile Lithopoma

americanum and juvenile Batillaria minima snails and a no-snail control in replicate 38-L glass aquaria.

Each of three replicate aquariums per treatment contained a total of 10 tiles with recently settled, visually

healthy, A. cervicornis. Tiles were photographed and monitored every three weeks for five months to

analyze coral growth, coral survivability, algal growth and crustose coralline algae growth. Labor involved

in coral husbandry was quantified. Results indicate significant improvements in growth performance when

staghorn coral recruits are raised with L. americanum in comparison to treatments absent of herbivores.

Further, including snails decreases labor required for juvenile coral husbandry. These results suggest that

rearing staghorn coral recruits with L. americanum contributes to improved outcomes for sexual

propagation.

Risk-based approach to evaluate alligator gar Atractosteus spatula aquaculture in Florida

Lauren N. Lapham Tropical Aquaculture Laboratory, Program in Fisheries and Aquatic Science, School of Forest Resources and Conservation,

Institute of Food and Agricultural Science, University of Florida, Ruskin, FL.

Corresponding author: Lauren Lapham, l.lapham@ufl.edu

Alligator Gar Atractosteus spatula is imperiled throughout much of its native range, being rare or

extirpated in 6 of 14 U.S. states. It is of conservation concern in its small portion of the Florida Panhandle

where it is native. Few data exist for Alligator Gar in Florida; therefore, the Florida Fish and Wildlife

Conservation Commission implemented a harvest closure in 2006, making it illegal to take or possess

Alligator Gar without a permit. FWC will issue permits for scientific research and management efforts.

There is interest in Florida to culture Alligator Gar for food and out-of-state sales as ornamentals; activities

currently not permitted. Although Alligator Gar is imperiled, there is concern for invasiveness if

regulations are changed to allow for commercial aquaculture in Florida. Before making decision

concerning commercial aquaculture, it is prudent to evaluate the risk of establishment and impact. Risk of

invasiveness will be assessed through an extensive literature review and biological synopsis, risk screens,

and a stakeholder-inclusive qualitative risk assessment. The biological synopsis will provide considerable

information on the species biology and potential invasiveness. Fish Invasiveness Screening Kit (FISK)

assessments will provide a preliminary risk estimate. A stakeholder panel will consist of experts in state

and federal agencies, academia, or other organizations and will further evaluate invasiveness risk.

Research and management recommendations arising from risk-based process will be available to agencies

and industry to support decision making regarding permitting, restricting, or prohibiting aquaculture of

Alligator Gar.

Distribution of oyster predators across environmental gradients in Cedar Key, FL

Gabrielle Love Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, University of Florida, Gainesville, FL

Corresponding author: Gabrielle Love, glove@ufl.edu

Oyster reefs are an ecologically and economically important system that have been declining in

abundance and extent in the Gulf of Mexico due to a variety of possible factors, prompting efforts to

improve management, restore reefs, and add to our understanding of oyster population dynamics. Among

the potential causes of oyster declines is increased natural mortality from predation by reef-

dwelling invertebrates, which is suspected to have been a driver of recent oyster fishery

collapses. Predators have strong salinity preferences, and their distribution and feeding habits respond to

changes in estuarine salinity resulting from droughts or high levels of precipitation. However, the spatial

preferences of these predators within estuaries in the Big Bend area of the Gulf of Mexico are not well

understood and documented. The aim of this study will be to gain a better understanding of predator

responses to changes in prey systems by conducting surveys of predator densities across a suite of

environmental conditions in the oyster reef estuary in Cedar Key, Florida. I plan to sample at various

locations around the estuary to compare predator assemblages and densities across salinity regimes, prey

densities, and at natural versus restored reefs. Comparing different predator densities will demonstrate

preferential habitat conditions for predators as well as relative risk of predation mortality by oysters in the

estuary. This work will improve understanding of predator movement and their foraging preferences in

this dynamic environment for use in oyster reef management and restoration planning to protect this

natural resource from additional mortality.

Symbiont uptake in the upside-down jellyfish. How do different strains of Symbiodinium impact

Cassiopea xamachana polyps?

Casandra R. Newkirk1, 3, Thomas K. Frazer1, 2, Mark Q. Martindale3 1School of Forest Resources and Conservation, Fisheries and Aquatic Sciences, University of Florida, Gainesville,

FL, 32611, USA 2School of Natural Resources and Environment, University of Florida, Gainesville, FL, 32611, USA 3The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA

Corresponding author: Casandra Newkirk, crnewkirk@ufl.edu

Symbiosis with algae in the genus Symbiodinium is common among many members of the phylum

Cnidaria. Increasing vulnerability of symbiotic cnidarians due to expulsion of symbionts

from hosts (bleaching) has become a more concerning issue as sea temperatures rise. The ability of some

cnidarian species to resist and better withstand stress factors that cause bleaching, is based around the

adaptive bleaching hypothesis. This hypothesis states that cnidarian hosts have the capacity to select for

distinct strains of zooxanthellae following a bleaching event and, in doing so, are likely to exhibit

increased resistance to future bleaching events. Polyps of the scyphozoan jellyfish, Cassiopea

xamachana, are being used as model organisms in order to better understand this adaptive capability. The

study presented here focused on 1) whether polyps that have been previously bleached could maintain a

stable symbiosis with different clades of reintroduced Symbiodinium, and 2) would they allow them to

metamorphose into ephyra (strobilation). Following bleaching and recolonization of bleached polyps,

these preliminary results were documented: 1) Clade A strains CassKB8, CassEL1, and rt-379 all

successfully established a stable symbiosis that promoted strobilation; 2) strain Zs successfully

colonized polyps but no strobilation was seen to have occurred; 3) and strains rt-002 and Mf1.05b did not

establish a stable symbiosis with polyps (and did not strobilate). Strains that maintained a stable symbiosis

will be used in subsequent adaptive bleaching experiments to determine if strains with a higher tolerance

to heat will allow polyps to have a greater adaptability to future experimental bleaching.

Reproductive biology of female Atlantic yellowfin tuna from the Gulf of Mexico and U.S. Atlantic

coast

Ashley Pacicco1, Debra Murie2, Robert Allman3 1National Marine Fisheries Service-Riverside Technologies Inc. 2University of Florida, School of Forest Resources and Conservation

3National Marine Fisheries Service, Southeast Fisheries Science Center, Panama City Laboratory

Corresponding author: Ashley Pacicco, apacicco212@ufl.edu

Female yellowfin tuna (Thunnus albacares) have a relatively complex reproductive biology whereby

they release multiple batches of eggs over an extended spawning period once they reach sexual maturity.

To address spatial and temporal uncertainties in spawning and maturity, a total of 307 ovaries were

examined histologically from females captured in the Gulf of Mexico (GOM) (n=275) and U.S Atlantic

coast (n=32) during 2010-2017. Recreational hook and line was the most common gear type (92%)

followed by pelagic longline from commercial landings (8%). Yellowfin tuna lengths ranged from 697 -

1575 mm curved fork length (CFL). Each ovary was assigned to a reproductive phase based on the

presence of oocytes in different stages of development. As in previous studies, yellowfin tuna were found

to be batch spawners with asynchronous oocyte development and indeterminate fecundity. Post-ovulatory

follicles (POFs) in the ovaries, an indicator of recent spawning, were seen as early as March and as late

as December, indicating that yellowfin tuna have a protracted spawning season. Length at 50% and 95%

sexual maturity, defined as when the ovary has reached vitellogenesis, was estimated at 1020 mm and

1190 mm CFL, respectively. Batch fecundity counts (n=14) began when oocyte development

reached germinal vesicle migration (the onset of final oocyte maturation). Females release on average an

estimated 3.25 ± 1.4 million eggs per batch in the GOM. Increased sampling coverage of yellowfin

tuna gonads is warranted throughout the NW Atlantic for a comprehensive analysis of spawning

seasonality and sexual maturity.

Developing intensive aquaculture of the long-spined sea urchin Diadema antillarum as a tool for

coral reef restoration

Aaron Pilnick1, Keri O’Neil3, and Josh Patterson2 1School of Natural Resources and Environment, Institute of Food and Agricultural Sciences, University of Florida,

Gainesville, FL 2Fisheries and Aquatic Sciences, Institute of Food and Agricultural Sciences, University of Florida, Apollo Beach, FL 3The Florida Aquarium, Apollo Beach, FL

Corresponding author: Aaron Pilnick, apilnick@ufl.edu

The long-spined sea urchin (Diadema antillarum) was once an abundant reef grazing herbivore throughout

the Caribbean. Benthic surveys conducted in the Florida Keys during the 1960s-70s revealed average

densities of 5-10 individuals/m2. During the early 1980s, 98-99% of Diadema populations disappeared

due to disease that appeared to originate at the Panama Canal. Sudden and considerable population

reductions from this event resulted in a lack of reef herbivory, and contributed to ongoing ecological shifts

from hard coral dominated reef systems towards macroalgae dominated reef systems throughout the

Caribbean. Lack of natural recovery and drastically reduced population sizes since the early 1980s

necessitate exploring Diadema restocking as part of an overall reef restoration initiative. Intensive

aquaculture is a potentially viable method for producing individual Diadema for restoration purposes. The

purpose of this study is to refine methodologies for reliable ex situ reproduction and larval rearing of

Diadema in a closed recirculating aquaculture system (RAS). The intention of this work is to improve the

viability of large-scale aquaculture for future experimental restocking. This presentation outlines the

research methods and experimental design conducted in a novel RAS at The Florida Conservation and

Technology Center, alongside the Florida Aquarium in Apollo Beach, Florida.

Pioneer snook: Tracking the genetic effects of settling territory in the Big Bend region of Florida

Emma Pistole1, Micheal Allen2, and Michael Tringali3 1 UF IFAS SFRC Fisheries and Aquatic Sciences 2 UF IFAS Nature Coast Biological Station 3 Florida Fish and Wildlife Conservation Commission

Corresponding author: Emma Pistole, epistole@ufl.edu

The Common Snook (Centropomus undecimalis) is a highly sought-after sport fish in Florida. The species

supports a large, predominantly catch and release fishery with 2.1 million fish caught each year. Common

Snook were historically found in high abundance in Florida between Tarpon Springs in the Gulf of Mexico

(GOM) and Cape Canaveral in the Atlantic. However, since 2013, Common Snook abundance in the Big

Bend region of Florida has increased exponentially. Researchers hypothesize that this recent range

expansion may be due to rising local sea surface temperatures. Common Snook are currently managed by

the Florida Fish and Wildlife Conservation Commission as two distinct stocks, separated by coast.

However, there are no data about the genetic diversity of individuals in the Big Bend region. Furthermore,

presence of young of the year in the Big Bend provides evidence for local spawning. Therefore, the goal

of this study is twofold. Firstly, we aim to investigate the genetic characteristics of Common Snook in the

Big Bend to determine if they are genetically distinct from the broader Gulf stock. Secondly, we aim to

estimate the number of parents that successfully contribute offspring to the region, utilizing genetic

techniques to determine close-kin relationships between individuals. Information concerning recruitment

connectivity, spawner abundance, levels of genetic diversity, and geographic patterns of kinship for

individuals from the Big Bend will help ensure that these newly established Common Snook populations

are assessed and managed appropriately.

Effects of 17α-methyltestosterone immersion and feeding on masculinization of the dwarf gourami

and rosy barb

Shane W. Ramee1, Taylor N. Lipscomb1, and Matthew A. DiMaggio1 1 Tropical Aquaculture Lab, School of Forest Resources and Conservation, University of Florida/IFAS, Ruskin, FL

Corresponding author: Shane Ramee, sramee@ufl.edu

In many parts of the world, it is a common practice to use hormones to masculinize sexually dichromic

ornamental species in which males are more ornately colored and therefore more aesthetically attractive

and valuable. The synthetic androgen 17α-methyltestosterone (MT) is one of the most common hormones

used in this practice due to its proven efficacy in a wide range of species. The use of MT in ornamental

aquaculture is currently prohibited in the U.S. However, as regulations are constantly evolving,

indexing of MT under the Minor Use and Minor Species Health Act (MUMS) remains of great interest to

ornamental aquaculture stakeholders. The Rosy Barb Pethia conchonius and Dwarf

Gourami Trichogaster lalius are two sexually dichromic species that were specifically identified by

commercial producers as species which would benefit from masculinization and identification of

efficacious doses and administration routes for MT may be prudent. The current study seeks to identify

the minimum effective dose of MT for each species. Larval Dwarf Gouramis and Rosy Barbs were

exposed to a range of concentrations of MT over the first 30 or 50 days post hatch. MT was administered

either through a regime of 4-hour immersions or via top-coated feed. Survival was determined at the end

of each treatment regime and the fish from each replicate tank were grown out for approximately 2-3

months, until sex ratios could be determined via gross dissections. Final sex ratios were evaluated to

determine the minimum effective masculinizing MT dose for both immersion and feeding.

Common bottlenose dolphin (Tursiops truncatus) distribution and abundance in

the brackish environment of Sabine Lake, northwestern Gulf of Mexico

Errol I. Ronje1 1 University of Florida, School of Forest Resources and Conservation, Gainesville, FL 32611

Corresponding author: Errol Ronje, errol.ronje@ufl.edu

Information on common bottlenose dolphin (Tursiops truncatus, Montagu, 1821) distribution in bays,

sounds, and estuaries is lacking throughout portions of the southeastern United States, northwestern Gulf

of Mexico, including areas of Texas and western Louisiana. Exploratory surveys conducted in the brackish

estuary of Sabine Lake on the Texas / Louisiana border confirmed the presence of numerous common

bottlenose dolphins, prompting systematic surveys to examine spatial and temporal distribution

patterns. Fourteen surveys, using photographic identification capture-mark-recapture techniques, were

conducted during the winter and summer of 2017. Seventy-nine (winter=32, summer=47) bottlenose

dolphin groups were encountered and photographed. Abundance estimates derived from closed capture

models resulted in an estimate of 102.96 / 186.68 (winter / summer) for the Sabine Lake bottlenose dolphin

population. A transect-line hotspot analysis (Getis-Ord Gi*) indicated dolphin group density was spatially

clustered in the navigation channels and coastal waters adjacent to the Sabine Pass Channel (p < 0.001). A

zero-altered gamma model indicated dolphin group density was positively correlated with slope, and

dolphin group presence was positively correlated with slope, depth, and distance to the coast. The

distribution results and abundance estimates provided here are the first indications of a bottlenose dolphin

population with site-fidelity to Sabine Lake. These data are part of a multi-bay abundance and distribution

assessment for bottlenose dolphins in the northwestern Gulf of Mexico, and will be evaluated in context

with future analysis of data collected in Galveston Bay, West Bay, and adjacent coastal waters.

The effects of predatory drills on Florida bay scallop growth, mortality, and parasite load

Abigail K. Scro1, and Donald C. Behringer1,2 1 Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL 2 Emerging Pathogens Institute, University of Florida, Gainesville, FL

Corresponding author: Abigail Scro, a.scro@ufl.edu

Drills are a type of predatory gastropod that feed on molluscs such the eastern oyster Crassostrea virginica

and the bay scallop Argopecten irradians. They have been known to eliminate entire oyster reefs and drive

declines in commercial and recreational fisheries. Florida has a popular recreational fishery for bay

scallops in the Gulf of Mexico but heavy infestations of drills have recently been observed on some scallop

beds. However, the abundance and potential effects of drills on scallops has not been well studied. Not

only can heavy predation from these snails cause population declines but sublethal drill predation has the

potential to transmit disease from infected to healthy individuals or between different molluscan species,

which could have further population and fishery implications. The goal of this study will be to determine

the potential threats of drills on scallop growth, mortality, and disease. Specific objectives will include:

1) Surveys to determine the distribution and abundance of drills on scallops along Florida's Nature Coast;

2) Analysis of scallop and drill tissues to construct disease profiles for these species; and 3) Laboratory

choice experiments to test the prey preference of drills and feeding transmission experiments to determine

if drills can serve as vectors for disease transmission.

The relationship between freshwater discharge and salinity on estuarine fish communities in

Cedar Key

Dylan Sinnickson Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, Nature Coast Biological Station, Institute of

Food and Agriculture Science, University of Florida, Gainesville, FL.

Corresponding author: Dylan Sinnickson, dsinnickson@ufl.edu

The Cedar Key estuary of Florida’s Big Bend Coastline has historically been a productive and diverse

estuarine ecosystem supported by significant freshwater inputs from the Suwannee River. In recent years,

significant changes in land use and climatic conditions have resulted in lower discharges from the

Suwannee River. Since 2003, the river has experienced four of its six most extreme low flow events in

the past 100 years. This study attempts to understand the impact of freshwater inputs from the Suwannee

River on the estuarine fish communities of Cedar Key. This will be done by utilizing Ecopath with Ecosim

to simulate salinity changes and the respective effects on the estuarine ecosystem. First, a mass-balanced

Ecopath model was created by assigning dominant taxa to functional biomass groups. In Ecopath, sixty-

one functional groups have been created for focal species using clustering techniques based on similar

biological characteristics such as diet composition and trophic level. Evaluations for density estimates

and diet compositions were made by analyzing data collected through the FIM program of FWC. For the

mortality, consumption rates, and ecotrophic efficiencies of each functional group, values were estimated

by reviewing the current literature on the study species. Following the completion of a balanced Ecopath

model, we will use the forcing function application of Ecosim to simulate salinity changes. This model

will demonstrate changes in populations affected by limited salinity tolerances as well as ecosystem wide

effects resulting from food web dynamics.