Transcript Asian Shore Crab

Heather Davidson
Patricia Madden
Rob Weinstein
7/29/2009
Background
 First recorded citing in Cape May, New Jersey in 1988.
 Thought to be introduced by ballast water of ships when
emptied into the ocean.
 Co-live in intertidal and subtidal waters under rocks with
native crabs.
 These crabs spawn between May and September
 Asian crabs are omnivores feeding on items such as
bivalves and seaweed.
Characteristics of Asian Shore Crab
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Ability to live off of a wide range of food types
Reproduce rapidly- females lay up to 50,000 eggs
Can stand varying temperatures and environments
Highly mobile
Have no natural predators in the invaded area.
Origins- Hemigrapsus sanguineus
 The Asian shore crab is originally from the coast of
Korea, China, Japan, and Russia
 Small species of crab that grows up to 45mm
 Range in color from dark brown to green
Hypothesis
 The environmental factors at the Sea Plane
Ramp at Jamaica Bay will provide a better
breeding habitat for the Asian Shore Crab than
the environmental factors at Raptor Point.
Investigational Questions
 Percent of males and females
 Percent of females that are gravid (have eggs)
 Amount of food sources
 Comparison of the number of crabs found at each
location
 Comparison of male and female carapace widths
 Types of crabs found at each site
Procedures
 A protocol was created and jobs were assigned.
 A quadrat was created by tossing a ball of newspaper and the
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GPS location was recorded
Three large rocks were chosen for sampling
The footprint of each rock was measured
All data was recorded pertaining to the plants and living
organisms living within the footprint.
Each rock was turned over and crabs were measured, sex was
determined (including gravid females).
All crabs, rocks and living organisms were returned to their
original position
Methodology Day 1 -July 17th
 We visited the Sea Plane
site location during low
tide.
 Study protocol and
procedures were
followed.
 Crabs were collected and
data was recorded.
 Rocks and crabs were
returned to their original
location.
Methodology Day 2
 We visited both Raptor’s
Point and the Sea Plane
Ramp locations
 Collected data and made
observations
 Measured crabs and
tried to identify them
with the data previously
recorded.
Data-7/17 Sea Plane Ramp
SEX RATIOS
20
18
Number of Crabs
16
14
12
10
8
6
4
2
0
FEMALE
MALE
Gender
* 7 female crabs were found with eggs.
Data-7/22 Sea Plane Ramp
SEX RATIOS
20
18
Number of Crabs
16
14
12
10
8
6
4
2
0
FEMALE
MALE
Gender
* Six female crabs were found with eggs.
Data-7/22 Raptor’s Point
SEX RATIOS
6
Number of Crabs
5
4
3
2
1
0
FEMALE
MALE
Gender
* No female Asian crabs were found with eggs.
Size Frequency Distribution (all
crabs)
Discussion
 Asian shore crabs were found in much greater
numbers at the Sea Plane Ramp location
 A greater number of breeding females were
found at the Sea Plane Ramp location.
 We believe that the Sea Plane ramp location has
a wider range of food sources and a greater
number of large rocks
References
"Invasive Species." Invasive Species. 5 Dec 2006. Arid Lands
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Information Center. 3 May 2008
<http://alic.arid.arizona.edu/invasive/index.shtml>.
"Protect Your Waters." Impacts. Aquatic Nuisance Species Task Force.
3 May 2008 <http://www.protectyourwaters.net/impacts.php>.
"Nonindigenous Species Information Bulletin." Asian Shore Crab. 10
Dec 2007. United States Geoplogical Survey. 3 May 2008
http://cars.er.usgs.gov/Nonindigenous_Species/Asian_shore_crab/asi
an_shore_crab.html
"Salt Marshes in New York City Parks - Jamaica Bay Park." Salt
Marshes in New York City Parks. 31 Oct 2001. New York City
Department of Parks and Recreation. 3 May 2008
<http://www.nycgovparks.org/sub_your_park/historical_signs/hs_hist
orical_sign.php?id=11326>.
"Index of Learning Theories and Models at Learning-Theories.com."
Learning Theories Knowledgebase. Nov 2007. LearningTheories.com. 17 Nov 2007 <http://www.learning-theories.com>.