News You Can Use

5 Best Crab Houses in the Chesapeake Region 

I've only been to two of them.

Scientists Sex Crabs

Environmentalists Try To Determine Gender Ratio Of Crabs

There are new concerns over the Chesapeake Bay crab population. Environmentalists worry that regulations to protect female crabs are causing a sperm shortage from the males.  Tim Williams looks at the new numbers and what they mean for your next crab feast.

In the dating world of crabs, it may take two but the current number of males to females is skewed.  “Male to female sex ratio has actually increased. That is, there are fewer females than males,” said Anson “Tuck” Hines, Smithsonian Environmental Research Center.

Traditionally, in Maryland and Virginia, male crabs, "Jimmies" are preferred over female crabs "Jennies" by people for the traditional crab feast, and command a higher price.  However, the females are caught in huge numbers for the picked crab trade.

One problem with evaluating the sex ratio of crabs is that crabs seem to have sexual preferences in the region of the Bay they utilize.  Male crabs favor lower salinity regions of the upper Bay and tributaries, where as females are found in higher abundance in the main Bay, and lower, more saline areas of the tributaries.  This is exacerbated by the trend toward sex selective fishing.

Results of the latest independent survey census or dredge survey done this winter show the number of female crabs has decreased in abundance for the second straight year while juvenile crabs have increased. The result is confusing fishery managers. “The ultimate goal of having more baby crabs is to have more adult crabs that are back into the fishery,” Hines said.

The new findings are a complete turnaround from recent results. In January, there were three females to every male. We are now closer to the ideal number of eight males to every female.

We have concerns because the crabs are closer to the ideal sex ratio than we can account for?  Are we looking a gift horse in the mouth, or what?

Since regulations in Maryland, Virginia and the Potomac River currently prohibit overfishing of females, the questions over where the females have gone and the timing of their cycles still remain.

Could it be that the number of female crabs being taken is being under reported? Naw; watermen would never cheat on quotas or other regulations...

“There’s a very narrow window in their life cycle in which they mate and receive all the sperm that they’re gonna need and use for their lifetime. If there’s not a male fully charged and ready to go at that point, it doesn’t happen as effectively,” Hines said.

A female crab's sex life is short, if not sweet.  Upon attaining full size, female crabs undergo "terminal molt", one which leaves them with adult characteristics, and fertile.  They can only be fertilized by males for a short period before their carapace fully hardens.  Meanwhile, the males continue to grow (and be harvested).

Still, the overall blue crab numbers are good which, in a nutshell, means enough of both sexes to go around.

The latest crab assessment suggests that studying the ratio should be a research priority to understand potential problems with the population in the future.

Years ago, I helped with a long term crab monitoring project here in the main Bay in the region off "Location" X.  Still lots of stories to tell from that.  Do have any idea how hard a big Jimmy can pinch a finger tip?  It still throbs when I think about it.

Sweating at the Beach, 7/7/12

Another hot, muggy day, well into the lower 80 F when we left for the beach at 7:40 AM, and up to 89 F by the end of our walk.  It was also pretty close to breeze-less so there wasn't even much relief there.

But the Ospreys and their young have to eat even on the hot days, and since they have to mostly supply the eagles too, they don't get a break from the heat. Notice the fish in it's grip.  We also had a bunch of dragonflies again, but not as many as on July 4.

We had the beach pretty much to ourselves. Only a few people were out to enjoy what was likely the best weather of the day.  I might have to visit later today just to see if it gets more use later.

Bait fish, probably Menhaden, schooling in the shallow waters.  No sign that anything was chasing them,

The shallows were busy today, lots of small crabs and small fish scurried away when we walked through.

Blackberries, some ripe, growing amongst the other vines on the cliffs.

OK, that's enough, can we go home to the air conditioning now?

Will Coal Burning Power Plants Make Super Crabs?

Carbon Dioxide Pollution Bulks Up Blue Crabs

The world’s oceans are changing, with waters today about 30 percent more acidic than they were two centuries ago, before the Industrial Revolution, according to the National Oceanic and Atmospheric Administration. Scientists say this is because the burning of coal, oil, and gas released a huge amount of carbon dioxide into the atmosphere that was absorbed by the water.

Of the CO2 added to the atmosphere by the burning of fossil fuels, about half appears to accumulate in the atmosphere, the other half being sequestered by either the ocean or terrestrial carbon sinks.  Scientists are still trying to quantify those fluxes, but yes, a lot of carbon is disappearing into the ocean. 

The chemical reaction between this pollutant -- C02 -- and water creates carbonic acid, according to Dr. Ries and other researchers.

Uh, that particular reaction has been known for a very long time.The only research needed is to read standard texts on water chemistry.

To discover how different forms of life will react to ocean acidification, Dr. Ries performed an experiment by growing 18 different species in laboratory tanks with varying levels of carbon dioxide. The result: the shells of crustaceans, including blue crabs, grew faster and larger in lab tanks with higher carbon dioxide levels.

Meanwhile, creatures that crabs eat—such as clams and oysters – suffered because of the pollution, with their shells becoming thinner and more fragile and growing more slowly.

More acidic water (by virtue of adsorbing CO2) has less of it's CO_2, in the form of  carbonante ion (CO₃^2-) and more as bicarbonate (HCO₃^-).  Carbonate is used by most shell forming organisms to form calcium carbonate (basically limestone), and decreased the carbonate decreases energetic ability to make the calcium carbonate.  It may or may not decrease actual calcification; it depends very much on the organism and the levels of carbonate (and hence pH).  And the paper tends to show that higher CO2 favors calcification by crabs, shrimp and lobsters, and decrease the calcification of bivalves.

So will this mean the crabs of the future will be super crabs, breaking everything in sight?  I doubt it.  The daily fluctuations of pH and carbonate ion in the Chesapeake Bay currently can be greater than his range of testing.