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.

Monday, June 30, 2014

High Crab Prices have South Carolina Crabbers Worried about Overfishing

Prices for high quality blue crabs have reached $100 per bushel. Some South Carolina crabbers are worried that the high prices have encouraged too many people to enter the fishery. Read more at the Post and Courier.

Female Blue Crab Harvest Reduced 10% in Virginia

Virginia Marine Resources Commission passed a 10% reduction in female blue crab harvests and will keep the winter dredge fishery closed for another year. These actions were taken in response to low numbers of female crabs in the 2014 winter dredge survey. The survey is conducted annually to determine the status of the blue crab population in Chesapeake Bay. Read more about Virginia's changes in the Washington Post.

Monday, June 9, 2014

Imported crab meat hits record prices

What was once a low-cost alternative to blue crabs from Chesapeake Bay and other parts of the US has reached record prices. Jumbo lump from the blue swimmer crab (scientific name Portunus pelagicus) has risen to $25 a pound. Blue swimmer crabs live in the Pacific Ocean and are harvested in countries including Indonesia, Thailand, and the Philippines. In this article from Undercurrent News (an seafood industry publication), the price increase is attributed to reduced supply, an increase in global demand, and issues with fishery sustainability. Time will tell whether this truly is a one-time perfect storm causing high prices or whether global demand is finally catching up with supply.

Thursday, May 1, 2014

Chesapeake Bay Blue Crab Population Declines, 2014 Dredge Survey Results Released

Blue crab populations in Chesapeake Bay are very low again this year, according to the results of the Winter Dredge Survey that were released earlier today. It is most concerning that the number of spawning age females has declined to the 4th lowest value since the survey began, below the minimum threshold established by fishery managers. Spawning age females represent the future of the crab fishery, as they will be the ones reproducing this summer. Protecting a sufficient number of these females from now until the end of this summer will be important to maximize reproduction and stabilize the population.

The one bright spot in the report is that the number of juvenile crabs increased 78% from last year's record low levels. This suggests that there may be more crabs around by late summer or fall of this year compared to 2013. However, juveniles in the dredge survey don't always survive to adulthood. As recently as 2012, record high numbers of juveniles in the dredge survey did not lead to a great fishing year.

Here's a link to the full press release from Maryland Department of Natural Resources.

Crabs on ESPN

When I'm not doing science, I'm a big sports fan. It's always funny to me when those worlds overlap. I was amused to see the headlines this morning that Heisman Trophy winning quarterback and baseball player Jameis Winston of Florida State was suspended from the baseball team for shoplifting crab legs and crawfish. Crabs will be on ESPN for days or weeks to come. Here's a link to the ESPN article and video.