Blue crabs plentiful despite bitter winter

Published 10:50 pm Tuesday, May 15, 2018

The Chesapeake Bay blue crab population remained healthy through an unusually cold winter and routine fluctuations and is primed for another year of harvesting, according to a recent survey.

The Virginia Marine Resources Commission released the results of the 2018 Blue Crab Winter Dredge Survey on May 9. Survey results showed that the abundance of female crabs that will spawn late May or mid-summer was estimated to be 147 million.

This projection is significantly less than the 254 million spawning age females in the Bay estimated for 2017, but that was the highest level ever recorded in the survey. It’s also below the 160 million average recorded in the last 10 years, according to the press release, but is still greater than the 82 million that was recorded on average annually from 1998 to 2007 when overfishing occurred.

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The press released stated that no overfishing has occurred since 2008, and that the 2018 female spawning stock is the ninth largest in survey history and well above the minimum safe threshold of 70 million spawning females that’s based on the control rule that established in the 2011 benchmark assessment.

“This all works out to be quite average,” Robert O’Reilly, VMRC chief of fisheries management, said in a phone interview.

The annual survey has been conducted by the Virginia Institute of Marine Science and Maryland’s Department of Natural Resources as the primary census of the Bay’s blue crab stock since the winter of 1989-1990. Crab dredges sample blue crabs at 1,500 sites throughout the Bay from December to March, when blue crabs are stationary and buried in the mud, allowing for more precise measurements.

Colder-than-average temperatures in January and March resulted in above-average mortality for adult crabs, per the press release, combined with 125 million juvenile crabs recorded last year, the fourth lowest in survey history. The total male and female abundance estimates for 2018 are 206 million, 38 percent lower than last year, but 10 million more than the 29-year average.

The 2018 survey results also estimate an increase in juvenile crab abundance by 34 percent to 168 million. These will grow large enough for commercial and recreational harvest late this season, per the press release.

Crab reproduction is vulnerable to habitat and weather fluctuations every year, and juveniles face greater variables for the month or so in the blue crab life cycle outside the watershed. Then there are natural predators when they return to the Bay.

“Management wants to ensure that there are as many female crabs as possible, but the spawning activity isn’t just related to the number of spawning parents that are out there,” O’Reilly said.

The results will be presented to the VMRC’s Crab Management Advisory Committee this Thursday to provide guidance for maintaining the blue crab stock and its fisheries this year. The Commission will be briefed on these survey results at its Tuesday meeting, followed by a public hearing on June 19.

The Chesapeake Bay Stock Assessment Committee, a subcommittee of the Sustainable Fisheries Goal Implementation Team, are reviewing the results and will release its full analysis in their 2018 Blue Crab Advisory Report this summer, which is used by managers to update fishery regulations.

“We don’t expect much change from last year at all, and I think the other jurisdictions are pretty much thinking that as well,” O’Reilly said.

Bay-wide commercial harvest in 2017 decreased by 9 percent, from 60 million pounds in 2016 to 54 million pounds. But the 2017 harvest was still 54 percent higher than 2014, the lowest annual harvest in nearly three decades. Virginia’s commercial crab harvest in 2017 was 23.5 million pounds, close to the 10-year average of 24 million pounds.

“We are fortunate that a shift to more responsible management of blue crabs in the past decade — including the closure of the winter dredge fishery — is allowing for sustainable harvests even in years with challenging environmental conditions,” Secretary of Natural Resources Matthew J. Strickler stated in the press release. “Continuing to manage for higher spawning female abundance will ensure we have enough blue crabs to support both commercial and recreational harvests and the Bay ecosystem.”