Spawning-age females increased substantially, but low reproduction means fewer crabs in the Bay
ANNAPOLIS — The Maryland Department of Natural Resources recently released the 2013 Blue Crab Winter Dredge Survey numbers, showing mixed results. The number of spawning-age females increased substantially this year – by 52 percent - indicating that the current management framework to protect adult female crabs is working. However, poor reproduction in 2013 and what appears to be high mortality within the record 2012 year-class resulted in an overall decline in the Bay-wide population.
At 147 million, the female population is more than double the scientifically-established, healthy-abundance threshold of 70 million. Total abundance of blue crabs dropped from 765 million to 300 million, and the number of juvenile crabs dipped from 581 million to 111 million.
“The results of this year’s winter dredge survey are by no means ideal, however, our strong management framework includes a buffer that allows the population to fluctuate within a safe threshold,” said DNR Secretary John Griffin. “In fact, the conservation measures we first put into place in 2008 were designed to allow for the naturally occurring fluctuations crabs are known for and ensure a sustainable seafood industry.”
While the percentage of mature females harvested in 2012 is projected to be under the safe target level of 25.5 percent for the fifth consecutive year, the dockside value of Maryland’s overall commercial blue crab fishery has increased significantly under the State’s conservation measures. The statewide dockside value ? which averaged 35.6 million from 2005 to 2007 - has increased 49 percent, since management changes were adopted, to an average of $52.9 million annually from 2008 to 2012.
Each year Maryland, Virginia and the Potomac River Fisheries Commission (PRFC) work together to determine if current management measures provide adequate conservation for the number of crabs estimated to be in the Bay. This ensures that harvest stays in balance with the population and maintains the strength of the joint management system. In response to these results, the jurisdictions are pursuing strategies to reduce the harvest of female crabs by approximately 10 percent.
“The Bay’s blue crab population varies naturally,” said DNR Fisheries Service Director Tom O’Connell. “Weather conditions, an increase in predators, or other natural occurrences can affect the crab stock. Our management system is also dynamic, and we will be working with the industry over the coming weeks to determine the best strategy to implement within our existing female crab management framework to achieve this reduction in 2013.”
The Virginia Marine Resources Commission (VMRC) expects to take comparable conservation measures. A daily bushel limit for 2013 has already been put into place, the first time in Virginia’s history that such year-long limits will restrict a harvester’s catch. The limits range from 27 to 55 bushels a day, depending on the number of crab pots a license holder is permitted. The survey results appear to require the continued closure of Virginia’s blue crab winter dredge fishery, which has been closed since 2008.The Potomac River Fisheries Commission (PRFC) also plans to take comparable conservation measures by adjusting their fall female crab closure periods.
“The strong partnerships we have developed with Virginia and the PRFC are providing a solid foundation upon which to rebuild the Bay’s blue crab population. We are extremely appreciative of their continued commitment to this effort,” said Griffin.
With harvest levels remaining below the scientifically-established target for half a decade the overall population decline observed in 2013 is not a result of fishing and overfishing was not occurring. Extremely low reproduction in 2013 combined with what appears to be high mortality on last year’s record year class resulted in an overall population dip this year.
Scientists believe that an unusually large influx of juvenile Red Drum may have contributed to the high mortality; these fish are highly predatory on young crabs and according to federal records, Virginia’s recreational anglers last year caught and released an astounding 2.5 million Red Drum – 40 times the 61,330 reported in 2011 and nearly 90 times the 28,580 reported in 2010. Although they are less common visitors to Maryland’s more northern waters, the State’s 2012 Red Drum harvest is estimated to be nearly 300,000 fish as compared to less than 3,000 in 2010 and 2011. Young blue crabs also prey on each other when densities are high as they were in 2012.
“It is important to keep these results in perspective: Five years ago this fishery was declared a federal disaster. That is no longer the case: overfishing is no longer occurring, a good fisheries management framework is in place, the stock is healthy and spawning-age females are doing well,” said VMRC Commissioner Jack Travelstead. “If not for the disappointingly small reproductive year class we would have much to celebrate.”
Maryland’s management system of daily catch limits and closed periods is designed to adapt and ensure that annual crab harvests stay balanced with annual shifts in abundance. Through a historic collaboration in 2008, Maryland, Virginia and the Potomac River Fisheries Commission took strong coordinated action to reduce harvest pressure on female crabs by 34 percent. At that time, scientists from all three jurisdictions deemed conservation measures necessary as blue crabs suffered near historic lows in spawning stock.
DNR and the Virginia Institute of Marine Science have conducted the primary assessment of the Bay’s blue crab population annually since 1990 [dnr.maryland.gov/fisheries/crab/dredge.asp]. The survey employs crab dredges to sample blue crabs at 1,500 sites throughout the Chesapeake Bay from December through March. Sampling during winter when blue crabs are usually buried in the mud and stationary, allows scientists to develop, with good precision, estimates of the number of crabs present in the Bay.
The Chesapeake Bay Stock Assessment Committee is reviewing the data and will begin drafting their 2013 Blue Crab Advisory Report over the next few weeks. The Potomac River Fisheries Commission plans to work with their Crab Advisory Committee to determine the best way to achieve comparable reduction measures this season.
Since 2011, Governor O’Malley and the Maryland General Assembly passed legislation that increased enforcement authority and penalties for egregious violations of striped bass, oyster and blue crab regulations and important measures to increase efficiency, flexibility and accountability in Maryland’s commercial fishing license system.
In 2008, NOAA’s National Marine Fisheries Service responded to Governor O’Malley’s request for disaster assistance funding for watermen impacted by the declining blue crab population. With support from Senator Barbara Mikulski and Maryland’s Congressional Delegation, DNR received $15 million to assist management efforts and mitigate the impacts from the blue crab fishery disaster. In 2009 and 2010, Governor O’Malley and the Maryland General Assembly also directed $6 million in capital funding toward these efforts. In further support of the industry, last year DNR launched the True Blue labeling and promotion program that will let restaurant-goers know whether their seafood dishes use meat from Maryland blue crabs or less expensive crabmeat from abroad.
For more information, visit: dnr.maryland.gov/fisheries/crab/dredge.asp
Source: Md. DNR