Corvina Drum Full Species Report

CORVINA DRUM – HOOK AND LINE CAUGHT

Cilus gilberti

Sometimes known as Corvina, Peruvian Corvina, Chilean Croaker, Corvinilla, Courbine Blonde

SUMMARY

Corvina Drum is a popular fish in South America, but little information exists on its biology,

abundance or fishery. They are found from Peru to Chile and around the Galapagos Islands, and

are caught by hook and line, longline and gillnets. The abundance of Corvina Drum is not known

but their landings have decreased over the past decade. Management is poor overall for Corvina

Drum, and essentially the fishery is unregulated. Hook and line fisheries generally cause little

habitat damage.

Criterion Points Final Score Color

Life History 1.50 2.40 - 4.00

Abundance 2.00 1.60 - 2.39

Habitat Quality and Fishing Gear Impacts 3.50 0.00 - 1.59

Management 0.50

Bycatch 2.00

Final Score 1.90

Color

LIFE HISTORY

Core Points (only one selection allowed)

If a value for intrinsic rate of increase („r‟) is known, assign the score below based on this value.

If no r-value is available, assign the score below for the correct age at 50% maturity for females

if specified, or for the correct value of growth rate ('k'). If no estimates of r, age at 50% maturity,

or k are available, assign the score below based on maximum age.

1.00 Intrinsic rate of increase <0.05; OR age at 50% maturity >10 years; OR growth rate

<0.15; OR maximum age >30 years.

2.00 Intrinsic rate of increase = 0.05-0.15; OR age at 50% maturity = 5-10 years; OR a

growth rate = 0.16–0.30; OR maximum age = 11-30 years.

Little information on the life history of Corvina Drum is available. They can reach a

maximum size of 1 m (Mann, 1954; Mejía et al., 1970), and population doubling time is

2-5 years (Chao and Robertson 2007). Species similar to Corvina Drum, such as corvina

reina from Costa Rica, have growth rates of 0.12 to 0.17 (Mug-Villanueva et al. 2005).

Orangemouth corvina (Mexico and USA), another similar species, reaches sexual

maturity around 50 cm for males and 59 cm for females (Prentice and Colura 2009). The

whitemouth croaker, a similar species also found in South America, reaches sexual

maturity between 2 to 4 years of age and lives to around 10 years of age (Fishbase 2011).

The life history information available for Corvina Drum and related species suggests a

middle score is appropriate.

3.00 Intrinsic rate of increase >0.16; OR age at 50% maturity = 1-5 years; OR growth rate

>0.30; OR maximum age <11 years.

Points of Adjustment (multiple selections allowed)

-0.25 Species has special behaviors that make it especially vulnerable to fishing pressure

(e.g., spawning aggregations; site fidelity; segregation by sex; migratory bottlenecks;

unusual attraction to gear; etc.).

Corvina Drum use nursery areas such as Playa Chipana in northern Chile (Vargas et al.

1999), which could make them susceptible to fishing pressure. Information on the habitat,

depth or for how long these nursery areas are used is not available. Because little

information is available, no points were subtracted.

-0.25 Species has a strategy for sexual development that makes it especially vulnerable to

fishing pressure (e.g., age at 50% maturity >20 years; sequential hermaphrodites;

extremely low fecundity).

-0.25 Species has a small or restricted range (e.g., endemism; numerous evolutionarily

significant units; restricted to one coastline; e.g., American lobster; striped bass;

endemic reef fishes).

Corvina Drum is found in the southeastern Pacific Ocean from Sechura Bay, Peru to

Lota, Chile (Mann 1954). This is a small range, so points are subtracted.

-0.25 Species exhibits high natural population variability driven by broad-scale

environmental change (e.g. El Nino; decadal oscillations).

It is likely that broad-scale environmental events effect Corvina Drum populations, with

higher abundances during El Nino years when water temperatures are higher. In Chile,

for example, abundances of Corvina Drum were 20.8% of the total catch in 1993 (El

Nino year), but <1% in 1989, 1990 and 1991 and have been absent from the catches since

1994 (Sielfeld et al. 2002).

+0.25 Species does not have special behaviors that increase ease or population consequences of

capture OR has special behaviors that make it less vulnerable to fishing pressure (e.g.,

species is widely dispersed during spawning).

+0.25 Species has a strategy for sexual development that makes it especially resilient to

fishing pressure (e.g., age at 50% maturity <1 year; extremely high fecundity).

Corvina Drum spawns in spring and summer, often in or near river mouths like the Loa

River in Chile (SAG 2000). There is no information available on the number of eggs

produced per spawning event, but drum species in general are considered broadcast

spawners (Locascio et al. 2007). Whitemouth croaker, a similar species for example will

produce between 2-13 million eggs per year (Manickchand-Heileman and Ehrhardt

1996). No points are added, because information specific to Corvina Drum is lacking.

+0.25 Species is distributed over a very wide range (e.g., throughout an entire hemisphere or

ocean basin; e.g., swordfish; tuna; Patagonian toothfish).

+0.25 Species does not exhibit high natural population variability driven by broad-scale

environmental change (e.g., El Nino; decadal oscillations).

1.50 Points for Life History

ABUNDANCE


Compared to natural or un-fished level, the species population is:

1.00 Low: Abundance or biomass is <75% of BMSY or similar proxy (e.g., spawning

potential ratio).

2.00 Medium: Abundance or biomass is 75-125% of BMSY or similar proxy; OR

population is approaching or recovering from an overfished condition; OR

adequate information on abundance or biomass is not available.

Information on abundance or biomass is lacking for Corvina Drum. Analysis of landings

data suggests declines of 30-40% over the past decade but this information does not

include catch-effort data (Chao and Robertson 2007), so it is unknown whether

abundance is decreasing or that less people are actively trying to catch Corvina Drum.

The IUCN Red List of Threatened and Endangered Species consider Corvina Drum to be

Data Deficient (Chao and Robertson 2007). Due to the lack of information, a middle

score was awarded.

3.00 High: Abundance or biomass is >125% of BMSY or similar proxy.


-0.25 The population is declining over a generational time scale (as indicated by biomass

estimates or standardized CPUE).

The abundance of Corvina Drum may be declining over generational time, as landings

have decreased during the last 10 years. But no hard evidence exists, so no points were

subtracted.

-0.25 Age, size or sex distribution is skewed relative to the natural condition (e.g.,

truncated size/age structure or anomalous sex distribution).

Corvina Drum reach a maximum size of 1 m (Mann, 1954; Mejía et al., 1970), but no

information is available about whether size patterns have changed so no points were

subtracted.

-0.25 Species is listed as "overfished" OR species is listed as "depleted", "endangered",

or "threatened" by recognized national or international bodies.

The IUCN Red List of Threatened and Endangered Species consider Corvina Drum to be

“Data Deficient” (Chao and Robertson 2007). No organization lists Covina Drum as

overfished, so no points were subtracted.

-0.25 Current levels of abundance are likely to jeopardize the availability of food for other

species or cause substantial change in the structure of the associated food web.

+0.25 The population is increasing over a generational time scale (as indicated by biomass

estimates or standardized CPUE).

+0.25 Age, size or sex distribution is functionally normal.

+0.25 Species is close to virgin biomass.

+0.25 Current levels of abundance provide adequate food for other predators or are not

known to affect the structure of the associated food web.

Corvina Drum are opportunistic predators that eat shrimp, crabs and bony fish such as

sardines (Vargas et al. 1999; Fernandez and Oyarzun 2001; Oyarzun et al. 2001 Fishbase

2011). There is no information available on whether current levels of abundance provide

adequate food for other predators, so we have not added any points.

2.00 Points for Abundance

HABITAT QUALITY AND FISHING GEAR IMPACTS


Select the option that most accurately describes the effect of the fishing method upon the habitat

that it affects

1.00 The fishing method causes great damage to physical and biogenic habitats (e.g., cyanide;

blasting; bottom trawling; dredging).

2.00 The fishing method does moderate damage to physical and biogenic habitats (e.g., bottom

gillnets; traps and pots; bottom longlines).

3.00 The fishing method does little damage to physical or biogenic habitats (e.g., hand

picking; hand raking; hook and line; pelagic long lines; mid-water trawl or gillnet;

purse seines).

Corvina Drum is caught using several methods including surface longlines, gillnets, and

hook and line. The longline fishery is common in central Chile (around Valparaiso). The

gillnet fishery for Corvina Drum (also around Valparaiso) fishes within one or two miles

of shore using nets with a mesh size of 20 cm (Simeone et al. 1999). There is little

information available on the Corvina Drum hook and line fishery, but this fishing method

generally causes little damage to the seafloor (Morgan and Chuenpagdee 2003), so we

have awarded a score of 3.


-0.25 Habitat for this species is so compromised from non-fishery impacts that the ability

of the habitat to support this species is substantially reduced (e.g., dams; pollution;

coastal development).

Corvina Drum is found over soft bottom habitats (Fishbase 2011) and is typically found

in inshore waters (Oyarzun et al. 2001). Mining activities in Chile have lead to the

dispersal of pollutants, including arsenic, into the surrounding waters, specifically in the

northern areas of the country (Richtera et al. 2004). However, research from central Chile

has suggested the effect of arsenic from mines seen in rivers has not yet reached the

adjacent marine system (Richtera et al. 2004). Due to the lack of information, we have

not subtracted any points.

-0.25 Critical habitat areas (e.g., spawning areas) for this species are not protected by

management using time/area closures, marine reserves, etc.

-0.25 No efforts are being made to minimize damage from existing gear types OR new or

modified gear is increasing habitat damage (e.g., fitting trawls with roller rigs or

rockhopping gear; more robust gear for deep-sea fisheries).

-0.25 If gear impacts are substantial, resilience of affected habitats is very slow (e.g., deep

water corals; rocky bottoms).

+0.25 Habitat for this species remains robust and viable and is capable of supporting this

species.

+0.25 Critical habitat areas (e.g., spawning areas) for this species are protected by

management using time/area closures, marine reserves, etc.

Although there are no areas closed specifically for Corvina Drum, there are a number of

Marine Protected Areas in their region (WDPA 2006) that likely protect Corvina Drum,

so we have added points.

+0.25 Gear innovations are being implemented over a majority of the fishing area to

minimize damage from gear types OR no innovations necessary because gear effects

are minimal.

Gear effects from hook and line fisheries are generally low (Morgan and Chuenpagdee

2003).

+0.25 If gear impacts are substantial, resilience of affected habitats is fast (e.g., mud or sandy

bottoms) OR gear effects are minimal.

3.50 Points for Habitat Quality and Fishing Gear Impacts

MANAGEMENT


Select the option that most accurately describes the current management of the fisheries of this

species.

1.00 Regulations are ineffective (e.g., illegal fishing or overfishing is occurring) OR the

fishery is unregulated (i.e., no control rules are in effect).

In Chile, the Under-secretary of Fisheries manages Chilean fisheries by providing policy

settings and regulatory framework (FAO 2000; OECD 2009). The Servicio Nacional de

Pesca (SERNAPESCA) is responsible for management and enforcement of fisheries

regulations (OECD 2009) and the Instituto de Fomento Pesquero (IFOP) is contracted to

carry out research (FAO 2000). Some management measures are that vessels used for

industrial fishing must be registered in the National Industrial Fisheries Register (FAO

2000) and artisanal fishing vessels must be registered in the Artisanal Fisheries National

Register (FAO 2000). There are no management measures specific to Corvina Drum in

place (Chao and Robertson 2007), so we have awarded a core point of 1.

2.00 Management measures are in place over a major portion over the species' range but

implementation has not met conservation goals OR management measures are in place

but have not been in place long enough to determine if they are likely to achieve

conservation and sustainability goals.

3.00 Substantial management measures are in place over a large portion of the species range

and have demonstrated success in achieving conservation and sustainability goals.


-0.25 There is inadequate scientific monitoring of stock status, catch or fishing effort.

There does not appear to be any scientific monitoring of stock status or fishing effort for

Corvina Drum throughout its range (Chao and Robertson 2007).

-0.25 Management does not explicitly address fishery effects on habitat, food webs, and

ecosystems.

Management does not explicitly address fishery effects on habitat, food webs or

ecosystems.

-0.25 This species is overfished and no recovery plan or an ineffective recovery plan is in

place.

-0.25 Management has failed to reduce excess capacity in this fishery or implements subsidies

that result in excess capacity in this fishery.

+0.25 There is adequate scientific monitoring, analysis and interpretation of stock status, catch

and fishing effort.

+0.25 Management explicitly and effectively addresses fishery effects on habitat, food webs,

and ecosystems.

+0.25 This species is overfished and there is a recovery plan (including benchmarks, timetables

and methods to evaluate success) in place that is showing signs of success OR recovery

plan is not needed.

+0.25 Management has taken action to control excess capacity or reduce subsidies that result in

excess capacity OR no measures are necessary because fishery is not overcapitalized.

0.50 Points for Management

BYCATCH


Select the option that most accurately describes the current level of bycatch and the

consequences that result from fishing this species. The term, "bycatch" used in this document

excludes incidental catch of a species for which an adequate management framework exists. The

terms, "endangered, threatened, or protected," used in this document refer to species status that is

determined by national legislation such as the U.S. Endangered Species Act, the U.S. Marine

Mammal Protection Act (or another nation's equivalent), the IUCN Red List, or a credible

scientific body such as the American Fisheries Society.

1.00 Bycatch in this fishery is high (>100% of targeted landings), OR regularly includes a

"threatened, endangered or protected species."

2.00 Bycatch in this fishery is moderate (10-99% of targeted landings) AND does not

regularly include "threatened, endangered or protected species" OR level of

bycatch is unknown.

Information on bycatch in the Corvina Drum hook and line fishery is not available. It is

likely that some other finfish species are incidentally caught but hook and line fisheries

tend to have low levels of this type of bycatch (Morgan and Chuenpagdee 2003).

Interactions with sea turtles and marine mammals are likely also low. We have assigned a

medium score to account for the lack of information.

3.00 Bycatch in this fishery is low (<10% of targeted landings) and does not regularly include

"threatened, endangered or protected species."


-0.25 Bycatch in this fishery is a contributing factor to the decline of "threatened, endangered,

or protected species" and no effective measures are being taken to reduce it.

-0.25 Bycatch of targeted or non-targeted species (e.g., undersize individuals) in this fishery is

high and no measures are being taken to reduce it.

-0.25 Bycatch of this species (e.g., undersize individuals) in other fisheries is high OR

bycatch of this species in other fisheries inhibits its recovery, and no measures are

being taken to reduce it.

Corvina Drum are caught as bycatch in the flounder gillnet fishery of Coquimbo Bay,

Chile (Hernandez et al. 2010). However, the extent of this bycatch is not known, so we

have not subtracted any points.

-0.25 The continued removal of the bycatch species contributes to its decline.

+0.25 Measures taken over a major portion of the species range have been shown to reduce

bycatch of "threatened, endangered, or protected species" or bycatch rates are no longer

deemed to affect the abundance of the "protected" bycatch species OR no measures

needed because fishery is highly selective (e.g., harpoon; spear).

+0.25 There is bycatch of targeted (e.g., undersize individuals) or non-targeted species in this

fishery and measures (e.g., gear modifications) have been implemented that have been

shown to reduce bycatch over a large portion of the species range OR no measures are

needed because fishery is highly selective (e.g., harpoon; spear).

+0.25 Bycatch of this species in other fisheries is low OR bycatch of this species in other

fisheries inhibits its recovery, but effective measures are being taken to reduce it over a

large portion of the range.

+0.25 The continued removal of the bycatch species in the targeted fishery has had or will

likely have little or no impact on populations of the bycatch species OR there are no

significant bycatch concerns because the fishery is highly selective (e.g., harpoon; spear).

2.00 Points for Bycatch

REFERENCES

Chao, L. and Robertson, R. 2007. Cilus gilberti. In: IUCN Red List of Threatened Species.

Version 2010.4. Downloaded March 14, 2011.

Fernández, C. and Oyarzún, C. (2001), Trophic variations of the Chilean croaker Cilus gilberti

during the summer period 1997–98 (Perciformes, Sciaenidae). Journal of Applied Ichthyology,

17: 227–233. doi: 10.1046/j.1439-0426.2001.00273.

Fishbase. 2011. Micropogonias furnieri, whitemouth croaker. Accessed March 14, 2011.

Food and Agricultural Organization (FAO). 2000. Fishery country profile: The Republic of

Chile. FAO, Rome, Italy. 9 p.

Hernandez, S., Gonzalez, M.T., Villarroel, J.C. and Acuna, E. 2010. Seasonal variation in fish

bycatch associated with an artisanal flounder fishery on Coquimbo Bay, Chile. Revista de

Biologia marina y Oceannografia 45:695-703.

Locascio, J., Peebles, E. and Mann, D. 2008. Sound production and spawning by black drum

(Pogonias cromis) in southwest Florida. Proceedings of the 60th Gulf and Caribbean Fisheries

Institute, November 5-9, 2007. Pp. 591-595.

Manickchand-Heileman, S.C. and Ehrhardt, N.M. 1996. Spawning frequency, fecundity and

spawning potential of the whitemouth croaker Micropogonias furnieri in Trinidad, West Indies.

Bulletin of Marine Science 58:156-164.

Mann, G. 1954. Vida de los peces en aguas chilenas. Instituto de Investigaciones veterinarias:

Santiago, Chile. 342 p.

Mejía J., Samamé M. & Pastor A. 1970. Información básica de los principales peces de

consumo. IMARPE Inf. Esp. n° IM-62 - 20 p.

Morgan, L.E. and Chuenpagdee, R. 2003. Shifting gears: addressing the collateral impacts of

fishing methods in US waters. Pew Science Series. Washington, DC, Island Press.

Mug-Villanueva, M., Gallucci, V.F. and Lai, H.-L. 1994. Age determination of corvina reina

(Cynoscion albus) in the Gulf of Nicoya, Costa Rica, based on examination and analysis of

hyaline zones, morphology and microstructure of otoliths. Journal of Fish Biology 45:177-191.

Organization for Economic Co-operation and Development (OECD). 2009. An appraisal of the

Chilean fisheries sector. OECD Publishing.

Oyarzun, C., Fernandez, C., Landeta, M. and Cortes, N. 2001. Ontogenetic and temporal

fluctuations in feeding habits of the Chilean croaker Cilus gilberti (Perciformes, Sciaenidae) in

southern Chile. Cahiers de biologie marine 42:295-302.

Prentice, J.A. and Colura, R.L. 2009. Preliminary observations of orangemouth corvina spawn

inducement using photoperiod, temperature and salinity cycles. Journal of the World Mariculture

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Corvina Drum Full Species Report