RD519 - The 2017 Virginia Blue Crab Fishery Management Plan
Results from the 28th Bay-wide Winter Dredge Survey, conducted from December 2016 to March 2017 (Attachment 1). Table 2 presents 2008 to present data from the survey by the Virginia Institute of Marine Science and Maryland Department of Natural Resources. Recent results indicate the blue crab stock is not depleted and overfishing is not occurring. The 2016-2017 Winter Dredge Survey estimates of abundance of all size classes of crabs was 455 million crabs, and this total abundance is lower than the estimate from the 2015-16 total abundance of 553 million crabs but near the long-term average total abundance of 457 million crabs. The most recent abundance of juvenile crabs enumerated from this winter survey was 125 million and the fourth lowest number of recruits since 1990 and well below the long-term survey average of 262 million juvenile crabs.
The importance of the juvenile crabs surveyed in wintertime is their contribution to the following late summer and fall harvest when they have recruited to harvestable size and their contribution to the subsequent year’s late May and July-August spawning periods.
The number of overwintering female crabs that could potentially spawn (if not harvested prior to the spawning seasons) in 2017 was 254 million and is the highest amount of spawning-age female crabs determined from this survey. The importance of the mature female crabs is their contribution to the spawning events in late May and July – August of the same year the Bay-wide Winter Dredge Survey is completed. These crabs also are important to the spring and early summer harvest, as a high proportion of the Virginia commercial and recreational harvests consist of female crabs.
Year-to-year variation in abundance of blue crabs can be expected as a result of the effects of environmental influences, especially for early life stages of crabs. Juvenile crab abundance can vary because of inter-annual difference in entrainment of crab larvae from the ocean to the Virginia portion of Chesapeake Bay that is subject to prevailing current and wind patterns. Environmental factors including weather conditions and predation can have an effect on all life stages of the crab population. Conservation of female spawning-age and juvenile crabs is the primary management objective to attempt to lessen variability of the blue crab stock abundance.
Since 2008, there has been a continuation by all Chesapeake Bay jurisdictions of management measures that conserve the spawning-age female crabs. The number of spawning-age female crabs, estimated in 2017 as 254 million, increased 31% from the 2016 estimate of 194 million. This increase may be partly attributed to the absence of a winter dredge fishery that has been closed since the 2008-09 winter in Virginia. That conservation measure allowed the juvenile crabs from the previous year to be free of fishing pressure after they matured in fall of 2016.
The relatively low overwintering mortality on spawning-age female crabs in the winter of 2017 also can be cited as a positive factor in the resulting high abundance of these female crabs. In addition, management measures from 2008 that were extensive and implemented throughout the Chesapeake Bay jurisdictions have helped to mitigate year-to-year variability in the fisheries that previously resulted in overfishing during many years (see Attachment 1).
The Chesapeake Bay jurisdictions have also relied on a new management framework for the past three season in which the fishery is regulated from July through July. The benefit of this approach is that two Bay-wide winter dredge surveys can be accomplished in that 12-month period, and conservation efforts can be applied after either survey is complete. Since 2014 the Virginia Marine Resources Commission (VMRC) and other Chesapeake jurisdictions no longer manage only the spawning-age female crabs but pay close attention the current year’s juvenile abundance, as the juveniles are the subsequent year’s spawning stock
Just two years ago, the low abundance (68.5 million) of spawning-age female crabs indicated a depleted stock, as an abundance below the threshold of 70 million spawning-age female crabs is considered depleted. Now, in 2017, the abundance of juvenile crabs is very low at 125 million, and predation and harvest in late summer and fall 2017 will determine how many of these juveniles in 2017 will mature as spawning-age female crabs in 2018 and join the mature female crabs that were not exploited by fisheries in 2017.
The VMRC, PRFC (Potomac River Fisheries Commission) and MD DNR (Maryland Department of Natural Resources) are agreed that before any substantial liberalization of current management measures concerning the blue crab occurs, the crab stock needs to stabilize at an annual abundance that consistently approaches the 215 million spawning-age female crab target. In response to the very low abundance of juvenile crabs in 2017, each jurisdiction implemented conservation measures to re-duce the harvest of juvenile crabs in the late fall or early spring or both periods.
The VMRC implemented additional, reduced bushel limits for November of 2017 and March of 2018 and reestablished the traditional crab pot season as a March 17 opening (in 2018) and November 30 closure in 2017. Previously, there had been a December 20 closure in 2016 and a March 1 opening of the season in 2017. The recent shift to a July to July crab management framework allows conservation of spawning-age female blue crabs in the spring prior to spawning and a portion of juvenile female crabs for the next year’s spawn.
In Virginia, maintained measures (since 2014) include reduced crab pot bushel and vessel possession limits for specific time periods and a shorter harvest season closure for all other crab gear that exploits juvenile (peeler-size) crabs. The reduced crab pot bushel limits extend from July 5, 2017 through July 4, 2018 for all crab pot license categories. Each year the VMRC can adjust measures based on results of the Bay-wide Winter Crab Dredge Survey, while depending on the bushel and vessel limits already in place to buffer inter-annual variability in juvenile crab production.
Virginia crab and oyster industries that benefitted from disaster relief funds initially provided in 2008 by the Department of Commerce for the declared Fishery Disaster in Chesapeake Bay blue crab fisheries continue to benefit today. The 2008 Disaster Relief Fund has provided various crab industry members (harvesters, buyers, and processors) negatively impacted by poor crab stock conditions during many years, through 2007, a source of employment. These funds have provided an opportunity to work in resource or habitat enhancement projects. The total amount of funding from the Disaster Relief Fund was $14,995,000. All of the six project areas detailed in previous reports have been completed and are shown in Attachment 4.