Thursday, July 24, 2014

With Too Few Male Blue Crabs, Reduction in Reproduction a Risk

A new study by my lab at the Smithsonian Environmental Research Center is featured on the Smithsonian Science website!

Male blue crabs can mate with multiple females. But with fewer men to go around, their female partners are left with less sperm to reproduce. (SERC image)

With too few males, blue crab population may be put at risk

The practice of selectively fishing male blue crabs in the Chesapeake—intended to give females a chance to reproduce—may have a hidden cost. A Bay without enough males could reduce the number of offspring females produce, ecologists at the Smithsonian Environmental Research Center wrote in a paper published in the July issue of Marine Ecology Progress Series.

Maryland and Virginia began reducing the harvest of female crabs by commercial and recreational watermen in 2008, the year officials declared the blue crab fishery a federal disaster. Since then, the crabs have shown signs of a shaky recovery. But a lasting comeback hinges on females producing enough offspring.

Click here for full article at Smithsonian Science...

There are likely to be multiple causes of the poor blue crab season this summer in Chesapeake Bay. The process of sperm reduction described in this article may be one of those causes but is not likely the most important factor. Other factors such as harvest, habitat loss, and disease likely have a greater impact on the population.

The article is based on:

Ogburn MB, Roberts PM, Richie KD, Johnson EG, Hines AH
Temporal and spatial variation in sperm stores in mature female blue crabs Callinectes sapidus and potential effects on brood production in Chesapeake Bay
MEPS 507:249-262

Tuesday, July 15, 2014

Rewards for Reporting Tagged Blue Crabs in Chesapeake Bay

Have you seen a crab in Chesapeake Bay wearing a pink tag on its back? If you have, please report the tag to us at the Fish and Invertebrate Ecology Lab at the Smithsonian Environmental Research Center. The tags are part of two studies on crab biology, migration, and fisheries. Rewards are $5 or $50 depending on which tag you find. Here's a close-up of the tag showing the information we hope you will record and information about how to report the tags::

Funding for this research was provided by Maryland Sea Grant and NOAA's Saltonstall-Kennedy Grant Program.