Blue Crabs of the Hudson River
Blue Crab Tagging Study
Project's Objective
NYSDEC started a tagging study in 2004 to gain information on the seasonal movements of the blue crab, Callinectes sapidus, spawning population. The study has continued yearly as we enter our 4th season in 2007. We are also looking to estimate fishing and natural mortality with our current data.
Known General Information from Other Estuaries/Areas
Much is known about blue crab, referred by many people as the blue-claw crab, biology and population movements in other water systems such as the Chesapeake and Delaware bays. It is generally known that blue crabs over winter in high salinity waters near the mouths of major fresh water inputs and bays. As water temperature warms and salinity increases the spawning population moves upstream in to fresh water to spawn. After spawning occurs crabs return to higher salinity waters to fertilize and release their eggs. The Hudson River has a robust blue crab population but it is unknown if the Hudson River stock mixes with other stocks (i.e. New Jersey; Delaware)
Methods
Each year 2000 crabs are caught and tagged in Newburgh Bay. Length, sex, stage, and catch per unit effort (number of crabs caught in a trap per hour) data are collected from each batch of crabs tagged. Recapture +data is recorded from call-ins from commercial and recreational fishers along the Hudson River and other New York marine waters.
Click on this graph to see a larger image.
The graph on the right shows the length frequencies of blue crabs recorded from 2004-2006. Click on the graph to see a larger image of this graph.
Interesting Finds
We have observed high percentages of male blue crabs at our study sites indicating that fresh water spawning habitat is dominated by the male portion of the population.
One of our crabs was tagged on 9-21-2006 and recaptured 7-14-2007. This crab had a carapace length of 177 and failed to molt for 297 days.
We have seen crab tag returns from as far north as Poughkeepsie and as far south as Raritan Bay.
Tagged Crabs
The yellow tags are located across the back (tagged crab to the left). The tag legend will have the tag number, NYSDEC research, and 845-256-3171. Call the phone number to report the catch information for your blue crab.
Foreign Invader
Please be on the lookout for the Chinese Mitten crab. The Chinese mitten crab, a non-native species from East Asia, is a costly and environmentally damaging invader in Europe and San Francisco Bay. One was caught in early June, 2007 in the Hudson River Tappan Zee section 27 miles upstream from the mouth. This is among the first caught in the eastern United States coastal waters. A few others have been caught in the Chesapeake Bay and Delaware Bay. If you see or catch one of these crabs please contact the Hudson River Fisheries Unit by phone, email or mail (contact information is on the right).
Blue Crab Regulations
Here are some highlights of the blue crab regulations that were effective in June of 2006.
- Hard crab 4 1/2 inch size limit
- Soft shell crab 3 1/2 inch size limit
- Peeler crab 3 1/2 inch size limit
More about Blue Crabs of the Hudson River:
- Length Frequency of Blue Crabs in the Hudson River - View a graph of blue crab length frequency from 2004-2006.
