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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. 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, including biology and population movements in other water systems such as the Chesapeake and Delaware bays. It is generally known that blue crabs overwinter in high salinity waters near the mouths of major freshwater inputs and bays. As water temperature warms and salinity increases, crabs move upstream into freshwater to mate. After mating occurs, female crabs return to higher salinity waters to 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 our goal is to catch and tag 2,000 crabs 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.

crab length frequency graph
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 freshwater 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 millimeters 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.

Blue crab with an across the back tag and an anchor tag

Tagged Crabs

There are two types of tags that you may find on a blue crab in the Hudson River. The first is a yellow tag that is located across the back of the crab. The second type is an anchor tag that will be orange or yellow and will be attached at the top of the right swimming leg. The tag legend will have the tag number, NYSDEC research, and 845-256-3171. Please 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 inch size limit

Other Blue Crab Projects

Commercial Blue Crab Monitoring

Blue crabs are sought after by both recreation and commercial fishers in the Hudson River Estuary. The blue crab project started in the fall of 1999, with the first field season in the summer of 2000.

Objectives:
How blue crab is measured

The objective of the project is to sustain and enhance the commercial and recreational blue crab fishery in the Estuary.

Methods:

To learn more about the commercial fishery a monitoring program was developed. This was done in part through on board observation of the commercial fishery. While on the fisher's boat, catch data was collected. The number and sex of the crabs was determined. Water quality data was also collected, such as dissolved oxygen, conductivity, and salinity. A subsample of crabs was measure and weighed.

Available Reports:
  • 2000 Blue Crab Report (364 KB pdf file)
  • 2001 Blue Crab Report (366 KB pdf file)

The reports are available for download from the menu on the right.

Overwintering blue crabs

In the winter of 2003, Normandeau Associates was hired to dredge three sections of the river for overwintering blue crabs buried in the mud. Sampling took place in Newburgh Bay, Tappan Zee Bay and in New York Harbor. They caught the majority of the crabs (90%) in New York Harbor and no crabs in Newburgh Bay.

Harvesting of crabs from the net

To obtain a copy of the final report by mail/email please send your name and address to us at our email or write to us at the address to the right.

Looking for More Information?

The Hudson River Blue Crab Guide (PDF, 383 KB) provides natural history and fishing information for these delicious, but feisty animals.


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