A Comparison of Site Fidelity of the Invasive Crab Hemigrapsus sanguineus and the Native Crab Panopeus herbstii

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1 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

2 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.

3 What is a native species? Species that were always there from what we know of, started there and derived from there.

4 Came from Japan Asian Crab 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 mm

5 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

6 Usually found in: Estuaries Mangals Burrows exposed to low tide Under stones & in oyster beds Atlantic Mud Crabs Panopeus herbstii *Native to Long Island Sound Prey includes: worms, mollusks, smaller crabs, plants Predators include: Post-larval & juvenile stages of fish within the mangroves Sharks, rays, crocodiles, barramundi

7 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?

8 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

9 Hypothesis The Asian Shore crab will have a lower level of site fidelity than the Mud crab, due to its invasive nature.

10 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

11 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

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13 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 # A M A M A M A M

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16 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

17 Results Is the Asian Shore crab a male dominated species? Is the Mud crab a male dominated species? Asian Crabs n= % % 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% Mud Crabs n= % 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% Fem ale Male Sexes of the Crabs 0.00% Fem ale Male Sexes of the Crabs

18 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%

19 Do the Asian Shore crabs have a larger range of carapace widths than the Mud crabs? Distribution of Carapace Widths of Asian Crabs n= % 40.0% 35.0% 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% Carapace Width (mm) Distribution of Carapace Width of Mud Crabs n= % 45.0% 40.0% 35.0% 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% Carapace Width (mm)

20 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

21 Is there a difference in the proportion of gravid females between the species? Percent Gravid vs. Not Gravid (Mud) 28% n=18 Gravid Not Gravid Percent Gravid vs. Not Gravid (Asians) 72% n=43 40% Gravid Not Gravid 60%

22 4. Is there a difference in the proportion of gravid females between the two species? Asian Shore crabs 60% gravid Mud crabs 72% gravid

23 Is there a difference in carapace widths between the sexes of crabs? Carapace Widths of Female Asian Shore Crabs n= Carapace Widths Carapace Widths of Male Asian Shore Crabs n= Carapace Widths

24 Carapace Widths of Male Mud Crabs n= Carapace WIdths Carapace Widths of Female Mud Crabs n= Carapce Widths

25 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 S.D: 3.57mm Mean: 20.4mm S.D: 5.93mm Mud- Female mostly between 14-18mm; many males between 14-22mm Female Male Mean: 14.5mm S.D:1.53mm Mean:16.94mm S.D:3.41mm Female Crab Male Crab

26 Is there a difference in site fidelity between the native and invasive species? Difference In Site Fidelity of Native and Invasive Species Asian Species Mud n=109 Difference In Site Fidelity of Native and Invasive Species Asian Species n=109 Mud

27 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

28 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.

29 Future Research Questions Does temperature affect the site fidelity of crabs? Is there a difference in site fidelity between the sexes?

30 Bibliography "Asian Shore Crab." Asian Shore Crab. N.p., n.d. Web. 23 July 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): 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 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): Web. 23 July Issg Database: Ecology of Hemigrapsus Sanguineus." Issg Database: Ecology of Hemigrapsus Sanguineus. Invasive Species Specialist Group, 16 Nov Web. 24 July "Black-fingered Mud Crab." The Uncommon Guide to Common Life on Narragansett Bay, Web. 22 July "Mud Crabs." Department of Fisheries Western Australia. Government of Western Australia, 6 Nov Web. 22 July <

31 Professors McSweeney and Brousseau for working with us on this project. NIH and NIMHD for helping with the funding for this program.