Overfishing, if left unchecked, may shrink size of snow crabs

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Overfishing, if left unchecked, may shrink size of snow crabs

November 17, 2018 - 17:50
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About 80 percent of snow crabs in Newfoundland and Labrador are below fishable size, according to research by a government body.

Two snow crabs in Bonne Bay, in Newfoundland, Canada.

With eighty percent of the snow crabs in Newfoundland and Labrador currently smaller than fishable size, Canada’s Department of Fisheries and Oceans (DFO) has warned that continued fishing pressure may lead to long-term harm to the species.

This news comes as harvest becomes progressively smaller in recent years, in what was once the world's largest snow crab fishery.

According to the research, overfishing had removed too many large male crabs from the population. And with fewer large males, the smaller male crabs terminally molt (meaning that they stop growing in size).

Describing the large crabs as superior breeders, Darrell Mullowney, a DFO biologist, says that they maintain the genetic hierarchy in the stock.

"[Small] crab used to have to grow large to compete with the larger individuals. In the absence of the larger individuals, there's no need for them to grow large anymore..." he added. In time, this can cause long-term harm to stocks through genetic change or impaired reproductive capacity.

However, because the fishermen are not allowed to use small mesh pots to catch the crabs, they, for the most part, do not see the undersized crabs. What they do notice is that there are fewer and fewer crabs when they haul in their catch in recent years.

Mullowney believes that the situation can be remedied: "If our interpretation of the situation is correct and this reflects the lack of competition from big males in the population, the answer is to reinstate some big males into the population."

"This is not irreversible harm or anything being done at this point that these things can't again grow large, and hopefully quite quickly, if we're able to re-establish a healthy population of big crabs," he adds.

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