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.