|
Japanese
Shore Crab
(Hemigrapsus
sanguineus) |
|
|
|
|
|
| Photo credit:
Copyright Koyou
Crab Information, Korea |
| Credit:
This web page was first developed by Jessica D. Sharon. |
|
 |
|
DESCRIPTION
The Japanese
shore crab’s identifiable features are a small hard bubble at the
crux of its claws; three spines along each side of its shell (carapace),
as opposed the similar-looking green crab which has five; and a
light-and-dark banding pattern on its legs. The crabs grow to about
the size of a silver dollar.
The crabs inhabit the rocky
intertidal zone — between the high tide line and about
one or two feet below low tide. They are omnivorous, eating macroalgae,
salt marsh grass, and small invertebrates such as amphipods, gastropods,
bivalves, barnacles and polychaetes.
To the south, the crabs’ diet consists of mussels, clams, periwinkles
and the European Green Crab (the latter two
are also non-native species). The crab is able to reproduce several times
a year. Whether the crab will have similar dietary preferences or be able
to reproduce as frequently in Maine’s colder climate remains to be seen.
|
Size
and Features:
2-3 inches, total width; carapace with three spines on each
side
Habitat:
Intertidal, rocky areas having cobble bottoms
Physical
Appearance: Light and dark bands along its legs; red spots
on its claws; and a body color ranging from pink to green to
brown and even purple, depending on where it is found
Seasonal
Appearance: Early spring to late fall
Behavior:
Aggregate under rocks; not overly aggressive (Neils Hobbs,
Department of Biological Sciences at the University of Rhode
Island.) |
| Photo credit:
Professor Larry Harris, University of New Hampshire
|
|
|
|
|
|
(Source: 1.
Japanese Shore Crab, Department of Marine Resource, http://www.state.me.us/dmr/rm/asian_shore_crab.htm
2. Creature Feature: Japanese Shore Crab; The Bay's Uninvited
Guest, by Mac Richardson, Save the Bay, http://www.savebay.org/aboutus/winter_01/html/creature_feature.htm)
|
|
|
|
|
IMPACTS The
Japanese Shore
Crab
is slowly overtaking the habitat of native crabs, such as green
crabs and mud crabs. This tiny invader is becoming more
dominant while the numbers of resident crabs slowly decline.
This is due, in part, because it is an opportunistic omnivore;
essentially eating anything that it's offered.
An omnivore with an appetite for
young clams, scallops, oysters, algae, fish larvae, and many other
species, these crabs may well pose a threat to New England
ecosystems and aquaculture operations. This new
competition in the food chain is leaving many other species
struggling. Although the total impact of this species is not
yet know, many are questioning whether or not there could be a link
between the recent collapse of the lobster population in Long Island
Sound, Maine. Others are concerned that perhaps there's a
connection between the rise of the Japanese crab and the decline of
the blue crab populations in the Chesapeake Bay.
(Source: 1. Tiny Invader Becomes a Bully in Local Waters, June
10, 2001, by John McQuiston, The New York Times http://www.seagrant.sunysb.edu/MediaArticles/NYT-ANS061001.htm
;
2. A Quick Guide to Marine Bioinvaders,
MIT Sea Grant College Program, http://web.mit.edu/seagrant/bioinvade/japcrab.html)
|
|
Top |
|
 |
ORIGIN
Japanese
Shore Crab was first identified on American shores in New Jersey in
1988. It's since made
its way as far north as Portland, Maine, and as far south as North
Carolina. The crab is indigenous to waters from southern Russia to
Hong Kong The Japanese
shore crab is invading Long Island Sound and crowding out native
species, according to marine biologists.
(Source: 1.
Japanese Shore Crab, Department of Marine Resource, http://www.state.me.us/dmr/rm/asian_shore_crab.htm
|
|
|
| DISTRIBUTION |
Link to Nonindigenous
Crustaceans in the United States
Distribution
Map (Florida
Caribbean Science Center)
Link
http://www.fcsc.usgs.gov/posters/Nonindigenous_Crustaceans/nonindigenous_crustaceans.html |
|
|
Crustaceans
(Focus
on the Great Lakes)
1999
Link |
Presented by Amy J.
Benson and Pam L. Fuller
U.S.Geological Survey, Biological Resources Division |
|
|
Top |
|
 |
Control
Japanese
Shore Crab
While there are
not yet chemical and biological methods to control this species,
there are many suggestions that can be followed in order to work
towards eradication. Suggestions include establishing a
database of current status of invasive species, monitoring changes
in "residency" of existing invasive species populations,
increasing public awareness, monitoring ballast water discharge from
freighters, and sending posters and fact sheets to parks, beaches,
or recreation areas.
Each person
plays an important role in preventing the introduction of
non-native species, Here are some suggestions on how you can
help:.
-
Don't
transport plants and animals when you travel or move without
checking with local authorities.
-
Never
release pets, aquarium plants or animals or non-native plants
into the wild.
-
Plant only
native plants on your property.
-
Be familiar
with the pathways through which non-native species can enter
our lands and waters and do your part to stop their accidental
release or movement.
-
Report any
sitings of known or suspected invasive species to your state
natural resource agency. A record of these sitings is
necessary to determine the distribution of these species and
monitor their effect.
(Source: 1. Three
new Exotic Species of the Chesapeake and Coastal Regions,
Maryland Recreational Fisheries, http://www.dnr.state.md.us/fisheries/recreational/articles/3exoticspp.html)
|
|
|
Top |
|
 |
|
|
|
Top
|
|
|
 |
|
|
|
Top
|
|
 |
Non-indigenous species facts:
Chinese Mitten Crab, Washington Sea Grant Program
Link http://www.wsg.washington.edu/outreach/mas/nis/mittencrab.html |
|
ID Booklet:
Illegal Aquatic Plants of South Carolina
(Free,
PDF file  ):
South Carolina Dept. of Natural Resources, Aquatic Nuisance Species
Program
Link http://water.dnr.state.sc.us/water/envaff/aquatic/lettuce.html
 |
|
Help Prevent the Spread of
Aquatic Plants and Animals (IL-IN-SG-98-1,
Free):
Illinois-Indiana Sea Grant
Link http://www.iisgcp.org/publication/br.htm
Fact
sheet describes how exotic aquatic species are spread by boaters.
Provides easy steps boaters can take to prevent spread of exotics
when transporting watercraft. 4p. |
|
The Ecology of the Japanese Shore Crab (Hemigrapsus sanguineus
De Haan) and its Niche Relationship to the Green Crab (Carcinus
maenas Linneus) along the Coast of Connecticut (Free):
Sea Grant Nonindigenous Species (Sgnis)
Link http://sgnis.org/publicat/2mb_16.htm |
|
|
 |
|
References
related to Japanese Shore Crab (provided by BayBulletin
Winter Volume 31, Number 1 (Creature Feature: Japanese
Shore Crab, The Bay’s Uninvited Guest, By Mac Richardson, Eelgrass
Specialist)
Link
http://www.savebay.org/aboutus/winter_01/html/creature_feature.htm
|
|
|
Top
Back to
Aquatic Exotic Animals & Plants
|
