June 7, 2012

 

US scientists working on lobster reproduction

 

 

US scientists and lobster fishery officials have been looking into the reproduction of lobsters in captivity as a precautionary measure.

 

In the Gulf of Maine, the amount of lobsters caught each year has rocketed over the past two decades. In 2011, more than 100 million pounds of lobster worth US$330 million were landed in Maine.

 

But Brian Beal, a University of Maine at Machias professor and director of research at Downeast Institute, said hatching juvenile lobsters and releasing them in the ocean has posed many challenges: what happens to the lobsters upon release? Have any of them ever grown big enough to be sold in Maine? Do they ever settle to the bottom before being eaten by fish?

 

He has come up with a better way, he explained, by growing lobsters in a protected environment until they are big enough to settle to the bottom upon release, which may improve their survival rate, according to reports.

 

Beal has also devised a way to place identifying tags on them that will last through several sheddings, so if tagged undersized lobsters appear in traps, it will help officials document how many of them are surviving, he said.

 

"The larger the animal you put back in the ocean, the better its chance of survival," Beal noted.

 

He thought of placing small lobsters in artificial shelters in the ocean and letting the natural currents provide them with food. The lobster could then grow over several months.

 

"Determining the flow is critical," Beal said about what size aperture in the container is optimal for letting food flow in and sediment flow out.

 

He also established that juvenile lobsters that are the same age and from the same female can grow at different rates contingent depending on how large a container they are put in: while a one-inch lobster can double in size over several months in a relatively small container, an identical lobster in a larger container the size of a shoebox can grow to six inches in the same time period.

 

"The lobsters grew to the size of the container," Beal said. "The larger the container, the larger the lobster."

 

The findings were recently published in the Journal of Shellfish Research.

 

Bob Bayer, a professor of animal science at University of Maine and executive director of the university's Lobster Institute, said there might be immediate demand or practical use for Beal's findings in southern New England, where lobster stocks have lately plummeted.

 

"That would be the place to test it," Bayer said about breeding lobsters for stock enhancement at a commercial scale.

 

Beal added that raising lobsters in captivity also brings other economic possibilities. For example, allowing those lobsters to be sold at a smaller size, as there could be different markets for smaller lobsters.