RD389 - The 2009 Virginia Blue Crab Fishery Management Plan


Executive Summary:
All findings from recent reviews of the status of the Chesapeake Bay blue crab stock indicate a major improvement in the abundance of adult crabs (age-1+). For the first time in 16 years, the abundance of age-1+ blue crabs has exceeded the target of 200 million crabs. The production of new crabs or recruits; however, remains low. For the twelfth consecutive year, the abundance of these age-0 crabs was less than the 1990 – 2008 average. This component of the stock provides harvestable size crabs in the fall, and, more importantly, represent an important fraction of the future spawning stock.

Results from the December 2008 to March 2009 Chesapeake Bay-wide Blue Crab Winter Dredge Survey indicate the abundance of age-1+ blue crabs was 223 million crabs. This value represents a 70% increase over the 2007-2008 survey value of 131 million. The estimate of 223-million harvestable-size crabs recorded from the winter dredge survey was substantially greater than the overfished threshold of 86 million recorded in 1999. This abundance of age-1+ crabs is above the interim target level of 200 million spawning age crabs established by the Chesapeake Bay Stock Assessment Committee (CBSAC). In January 2008, CBSAC established an interim target of 200 million spawning age crabs, based on analyses suggesting that 200 million age-1+ crabs is a minimum associated with consistently higher levels of recruitment.

The increase in abundance of spawning-age adults (male and female crabs), in the 2008-2009 Chesapeake Bay-wide Winter Dredge Survey, was mainly due to an increase in the number of female crabs that are likely to spawn in 2009. The abundance of male crabs in 2008-2009 was only 59 million crabs, and represented a more moderate increase than determined for female crabs. Data from three supporting blue crab surveys (the Maryland and Virginia trawls and the Calvert Cliffs Pot study) were reviewed. The results of these surveys were generally consistent, with the Chesapeake Bay-wide Blue Crab Winter Dredge Survey results, showing an increase in the abundance of adult crabs, and a continued low abundance of age 0 recruits.

The estimated 2008 Bay-wide crab harvest was 48.6 million pounds, slightly higher than the record-low 2007 harvest of 43.5 million pounds. The 2008 Maryland harvest is estimated to be 29.4 million pounds. The 2008 Virginia harvest was 16.7 million pounds, while 2.5 million pounds were reported harvested in the jurisdictional waters of the Potomac River Fisheries Commission. The poor Bay-wide commercial harvest was very near the intended 34% reduction (in pounds) of female crabs, from the average 2004-07 harvest. Similarly, the 2008 Virginia commercial harvest was 32.2% below the average 2004-07 harvest, and conservation measures were implemented in 2008 to achieve a 34% reduction in the harvest of female crabs. Nearly all conservation measures adopted by the Commission in 2008, were maintained for the 2009 crab fisheries, as discussed below.

Managers within the Chesapeake Bay continue to utilize the control rule, whereby annual estimates of abundance and exploitation rates are referenced against empirical and model-based standards, respectively, to guide management efforts. The control rule established an overfishing threshold, equal to an annual percentage harvest-removal rate of 53% and an overfished threshold of 86 million crabs, the lowest stock abundance recorded from the Chesapeake Bay-wide Winter Dredge Survey in 1999.

The percentage of the population of crabs removed by commercial and recreational fishing (exploitation rate or fraction) in 2008 was estimated to be 48%. This annual removal rate by fisheries is below the overfishing threshold of 53%, but above the target exploitation rate of 46%. In 8 of the last 11 years the exploitation rate has been above the threshold (53%).

It will take several years of maintaining an exploitation rate at or near the target level (46%), for this stock to sustain a spawning potential that will also provide improved harvests. Harvest information through July 2009 indicates that the increased abundance of harvestable-size crabs has contributed to a higher Virginia harvest of hard crabs, as compared to 2008. The harvest of hard crabs in the early months of 2009 is only 4% less than the average 2004-07 harvest through July. Less effort was also expended through July 2009 in the peeler crab fishery, but harvest (pounds) was about 30% less. Since May accounts for about 50% of the annual peeler crab harvest, it is expected that final 2009 peeler harvests (pounds) will be lower than in 2008. That decrease in peeler crab harvest is easily attributable to the fact that age-0 crab abundance has been well below the average.

Extensive steps were taken by the Marine Resources Commission, from 2007 to 2009, to gather scientific and industry expertise from the Blue Crab Regulatory Review Committee (2007), the Virginia Institute of Marine Science and the Commission’s Crab Management Advisory Committee. The Blue Crab Regulatory Review Committee was assembled by request of the Commission, as the Commission recognized the need for a peer-based review of the effectiveness of previously adopted conservation measures, for the blue crab resource. The findings of the Blue Crab Regulatory Review Committee were included in last year’s blue crab management plan but remain as a source of advice for the Commission. The final report is located at the following web address:
http://www.mrc.state.va.us/BCAC/Blue%20Crab%20Review%20Report%20March%202008.pdf

The Commission also reviewed the findings from the advisory reports conducted by the Chesapeake Bay Stock Assessment Committee, and the most recent advisory (2009) is detailed below (Attachment I). The Commission’s management process and actions, on behalf of the blue crab resource, are detailed, below, as the 2009 Virginia Blue Crab Fishery Management Plan.

The Commission has initiated several projects using federal disaster relief assistance funds ($14,995,000) to provide opportunities for eligible crab licensees to participate in resource or habitat conservation projects. The first project to be implemented was a work program, at a cost of $1.3 million, designed to assist 58 previously active crab dredge fishermen who were impacted by the closure of the 2008/09 winter crab dredge season. This work project was led by scientists from the Virginia Institute of Marine Science and extended from mid-December 2008 through mid-March and utilized side-scan sonar techniques to retrieve 8,790 derelict pots (“ghost” pots) in several areas of the Chesapeake Bay. Just under 5000 organisms, mostly blue crabs, were removed from the collected derelict pots. This project also removed other types of marine debris from the Chesapeake System (191 items) and identified five sunken vessels. As the Commission also closed the 2009/10 crab dredge season, the second year of this 3-year project is expected to get underway in early December. There will be 66 previously active crab dredge fishermen that take part in the second season of this program. The remainder of the programs that are funded by the disaster relief fund are discussed below, and a complete listing may be found in Attachment II.