Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
A Comparison of Site Fidelity of the Invasive Crab Hemigrapsus
sanguineus and the Native Crab Panopeus herbstii
Dr. Diane Brousseau
Dr. Laura McSweeney
Taylor Anderson
Katie Biardi
Christina Elmore
Jessica Ganim
Kristen Howell
Cecily Morales
Marisa Olavarria
Lauriana Soto
What is an invasive species? Non-native to the ecosystem under consideration and
whose introduction causes or is likely to cause economic
or environmental harm or harm the human health.
What is a native species? Species that were always there from what we know of,
started there and derived from there.
Asian Crab Came from Japan
Arrived at Long Island Sound in 1993
Spread from mid Atlantic to southern New England coast
Found in the intertidal/ sub tidal zone
Colors range from green to purple, from orange to brown
and red with spots
Males have a fleshy bulb in their claw
Adults range from 35-42 mm
Why is the Asian crab a
good invasive species? They are highly mobile
High tolerance for different environments
Consumes a wide variety of invertebrates (blue
mussel, snails) and seaweed
Opportunistic omnivore
Highly reproductive
Atlantic Mud Crabs
Panopeus herbstii
*Native to Long Island Sound
Usually found in:
• Estuaries
• Mangals
• Burrows exposed to low tide
• Under stones & in oyster beds
Prey includes:
• worms, mollusks, smaller crabs, plants
Predators include:
• Post-larval & juvenile stages of fish within the mangroves
• Sharks, rays, crocodiles, barramundi
Research Questions 1.) Is Asian Shore crab a Male dominated species? [Sex- ratio] Is
the Mud crab a Male dominated species?
2.) Do the Asian Shore crabs have a larger range of carapace widths than the Mud crabs?
3.) Is there a difference in site fidelity between the sexes?
4.) Is there a difference in the proportion of gravid females between the species?
5.) Is there a difference in carapace widths between the sexes of crabs?
6.) Is there a difference in site fidelity between the native and invasive species?
Site Fidelity 101 An Experimental Field Study of Site Fidelity and
Mobility in the Asian Shore Crab, Hemigrapsus
Sanguineus (Dr. Diane J. Brousseau, J.A. Baglivo, A.
Filipowicz, L. Sego, C. Alt).
Basis of Hypothesis and Experimental Design
Site Fidelity: The likelihood a species will return to
the same area, and will remain there over a period of
time
Hypothesis The Asian Shore crab will have a lower level of site
fidelity than the Mud crab, due to its invasive nature.
Materials and Methods Materials Used:
• Krazy glue
• Tab dividers
• Hole puncher
• Caliper
• Kim wipes
• Work gloves
• Buckets
• Bricks and cement blocks
• Mesh bags
• Plastic trays
Day 1: St. Mary’s by the
Sea
We collected both H. sanguineus and P. herbstii
The crabs were put in the saltwater tanks in the
laboratory for 2 hours
15 of each species were measured, tagged, and sexed
and then returned to the saltwater tanks overnight
Additional crabs were measured and sexed
Day 2: St. Mary’s by the
Sea 8 crabitats built at least 3 meters apart
15 crabs released into each crabitat
1 tag was lost at #7 and 1 crab was dead upon release
at #6
1 2 3 4 5 6 7 8
A M A M A M A M
Day 3: St. Mary’s by the
Sea
Returned to site about 24 hours later
Any tagged crabs remaining within a 1.5m radius of
the crabitats were recaptured
Sample size was decreased upon finding dead tagged
crabs in some crabitats
Results
Is the Asian Shore crab a male dominated species? Is the Mud crab a male dominated species?
Mud Crabs
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
Female Male
Sexes of the Crabs
Pe
rce
nt
of
Cra
bs
Asian Crabs
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
Female Male
Sexes of the Crabs
Pe
rce
nt
of
Cra
bs
n=118
n=81
1. Is the Asian Shore crab a male dominated species?
Is the Mud crab a male dominated species?
• Asian Shore crab, male percentage is about 72% while
female is about 28%
• Mud crab, male percentage is about 63% while female is
about 37%
Do the Asian Shore crabs have a larger range of carapace widths than the Mud crabs?
Distribution of Carapace Widths of Asian Crabs
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
45.0%
10.00-
15.00
15.00-
20.00
20.00-
25.00
25.00-
30.00
30.00-
35.00
35.00-
40.00
40.00-
45.00
45.00-
50.00
50.00-
55.00
55.00-
60.00
Carapace Width (mm)
Pe
rce
nt
of
Asia
n C
rab
s (
n=
11
8)
Distribution of Carapace Width of Mud Crabs
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
45.0%
50.0%
10.00-
15.00
15.00-
20.00
20.00-
25.00
25.00-
30.00
30.00-
35.00
35.00-
40.00
40.00-
45.00
45.00-
50.00
50.00-
55.00
55.00-
60.00
Carapace Width (mm)
Pe
rce
nt
of
Mu
d C
rab
s (
n=
81
)
n=118
n=81
2. Do the Asian Shore crabs have a larger range of carapace widths than Mud crabs?
Asian Shore crabs- carapace widths vary; widths between 10 mm and 35 mm
Mean: 19.08mm
Standard Deviation: 5.47mm
Mud crabs- carapace widths don’t vary much; widths are mostly between 10 mm and 20 mm with few between 20 mm and 35 mm
Mean: 16.28mm
Standard Deviation: 3.26mm
Is there a difference in the proportion of gravid females between the species?
Percent Gravid vs. Not Gravid (Asians)
60%
40%
Gravid
Not Gravid
Percent Gravid vs. Not Gravid (Mud)
72%
28%
Gravid
Not Gravid
n=43
n=18
4. Is there a difference in the proportion of gravid females
between the two species?
Asian Shore crabs – 60% gravid
Mud crabs – 72% gravid
Is there a difference in carapace widths between the sexes of crabs?
Carapace Widths of Female Asian Shore Crabs
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
10.00-
14.00
14.00-
18.00
18.00-
22.00
22.00-
26.00
26.00-
30.00
30.00-
34.00
34.00-
38.00
38.00-
42.00
42.00-
46.00
46.00-
50.00
Carapace Widths
Pe
rce
nt o
f C
ra
bs
Carapace Widths of Male Asian Shore Crabs
0
0.05
0.1
0.15
0.2
0.25
0.3
10.00-
14.00
14.00-
18.00
18.00-
22.00
22.00-
26.00
26.00-
30.00
30.00-
34.00
34.00-
38.00
38.00-
42.00
42.00-
46.00
46.00-
50.00
Carapace Widths
Pe
rce
nt o
f C
ra
bs
n=43
n=75
Carapace Widths of Female Mud Crabs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
10.00-
14.00
14.00-
18.00
18.00-
22.00
22.00-
26.00
26.00-
30.00
30.00-
34.00
34.00-
38.00
38.00-
42.00
42.00-
46.00
46.00-
50.00
Carapce Widths
Pe
rce
nt
of
Cra
bs
Carapace Widths of Male Mud Crabs
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
10.00-
14.00
14.00-
18.00
18.00-
22.00
22.00-
26.00
26.00-
30.00
30.00-
34.00
34.00-
38.00
38.00-
42.00
42.00-
46.00
46.00-
50.00
Carapace WIdths
Pe
rce
nt
of
Cra
bs
n=18
n=63
5. Is there a difference in carapace widths between the sexes of each species of crab?
Asian Shore- Female mostly between 14-22mm; many males between 18-34mm
Female Male
Mean: 16.78mm Mean: 20.4mm
S.D: 3.57mm S.D: 5.93mm
Mud- Female mostly between 14-18mm; many males between 14-22mm
Female Male
Mean: 14.5mm Mean:16.94mm
S.D:1.53mm S.D:3.41mm
Male Crab
Female Crab
Is there a difference in site fidelity between the native and invasive species?
Difference In Site Fidelity of Native and
Invasive Species
8.6
8.7
8.8
8.9
9
9.1
9.2
9.3
9.4
9.5
Asian Mud
Species
Pe
re
nta
ge
of
Cra
bs
Re
ca
ptu
re
d
Difference In Site Fidelity of Native and
Invasive Species
0
10
20
30
40
50
60
70
80
90
100
Asian Mud
Species
Pe
ren
tag
e o
f C
rab
s
Re
ca
ptu
red
n=109
n=109
6. Is there a difference in site fidelity between the native (Mud) and invasive (Asian Shore) species?
Asian percentage recaptured – 9.4%
Mud percentage recaptured – 8.9%
Unexpected results
Could get better results by:
- releasing more crabs
- better tide timing
- better weather
The data did not support our hypothesis that the Mud crab (Panopeus
herbstii) has a higher site fidelity in comparison to the Asian Shore crab
(Hemigrapsus sanguineus). There was not enough of a difference between
the number of crabs recaptured to suggest that there was any significance.
Future Research
Questions Does temperature affect the site fidelity of crabs?
Is there a difference in site fidelity between the sexes?
Bibliography "Asian Shore Crab." Asian Shore Crab. N.p., n.d. Web. 23 July 2013.
Brousseau, Diane J., Jenny A. Baglivo, Amy Filipowicz, Laurie Sego, and Charles Alt. "An Experimental Field
Study of Site Fidelity and Mobility in the Asian Shore Crab, Hemigrapsus sanguineus." Northeastern Naturalist
(2002): 381-90. Print.
Demeo, Anna, and John G. Riley. "Hemigrapsus Sanguineus(Asian Shore Crab) as Predator of Juvenile Homarus
Americanus(American Lobster)." (2006): 1-2. Web. 23 July 2013.
Epifanio, C. E., A. I. Dittel, S. Park, S. Schwalm, and A. Fouts. "Early Life History of Hemigrapsus Sanguineus a
Non- Indigenous Crab in the Middle Atlantic Bight(USA)." Marine Ecology Progress Series 170 (1998): 231-38.
Web. 23 July 2013.
"Black-fingered Mud Crab." The Uncommon Guide to Common Life on Narragansett Bay, 1998. Web. 22 July 2013.
http://www.edc.uri.edu/restoration/html/gallery/invert/black.htm
"Mud Crabs." Department of Fisheries Western Australia. Government of Western Australia, 6 Nov. 2013. Web. 22 July 2013.
<http://www.fish.wa.gov.au/Species/Mud-Crabs/Pages/default.aspx>.
Issg Database: Ecology of Hemigrapsus Sanguineus." Issg Database: Ecology of Hemigrapsus Sanguineus.
Invasive Species Specialist Group, 16 Nov. 2006. Web. 24 July 2013.
Professors McSweeney and Brousseau for working with us on this project.
NIH and NIMHD for helping with the funding for
this program.