The fact that only the claws are taken protects the crab population.
The crab populations on coral islands along the coast were also reduced to only a few percent of normal about nine months after the spill.
What is not known, he said, is what level of harvest is tolerable to the crab population.
A half-dozen surveys of the bay's crab population over the last decade show widely varying numbers, from hundreds of thousands to more than four million.
This loss is increasingly a threat to the crab population that has overtaken the oyster as the bay's main commercial harvest.
But fishery experts say signs of overharvesting are beginning to show in the crab population, too.
Mr. Munsen also doubted that the ban had any effect on crab population.
Several theories for the precipitous drop in the crab population have been proposed including overfishing, warmer waters, and increased fish predation.
Gwintinli is also home to the worlds largest crab population per square foot.
There are strict limits on the number of blue crabs they can trap, and the crab population has been shrinking for years.