Hatching solutions for the crab

Baltimore laboratory: Raising shellfish under microscope could offer hope for bay fishery.

April 26, 2001

RAISING blue crabs in hatcheries to restock the Chesapeake Bay would have been laughed at a few years ago as the equivalent of carrying coals to Newcastle.

But with commercial crab catches repeatedly reaching historic lows and annual dredge surveys reinforcing the sad story, that prospect could offer new hope for the declining fishery.

At the University of Maryland's Center of Marine Biotechnology, scientists using molecular genetics techniques are raising the tiny crustaceans in large tanks and small glass dishes.

Their immediate goal is to understand the life-cycle of the crab under controlled laboratory conditions. Numbers of lab-hatched juvenile blue crabs will be released into the bay to continue the study.

Success of this project at the Inner Harbor laboratory could lead to establishing a series of crab hatcheries around the estuary to restock it with young shellfish.

A similar program in Japan now results in the annual release of more than 50 million juvenile crabs into the wild, replenishing a once-depleted fishery.

Crabs are notoriously unpredictable, and the odds against a single larva growing to a full-sized adult are overwhelming. But a mature female lays millions of eggs at a time as a hedge against the high natural casualty rate.

Simply restocking the bay with hatchery crabs won't restore its former glory. Underwater grasses for shelter are a major factor. So are water quality, temperature and the abundance of predators.

Bay oysters have long relied on human efforts, planting spat and shell bars, to sustain their still admittedly meager numbers.

So the hatchery is no magic solution to the decline of the Chesapeake crab. But cutting-edge science of the Baltimore lab may yield a useful tool to aid its recovery.

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