RD287 - The 2007 Virginia Blue Crab Fishery Management Plan


Executive Summary:
The Chesapeake Bay blue crab stock is not overfished (an overfished condition would mean that stock maintenance capability could be jeopardized), and overfishing is not occurring.

All findings from recent reviews of the status of the Chesapeake Bay blue crab stock indicate a continuation of a low abundance of both exploitable size (2.4 inches and greater, in carapace width) blue crabs and mature female blue crabs. The most recent exploitation rate (2006 season) indicates that 50% of the stock is being removed, on an annual basis, strictly from harvesting activities. This 2006 exploitation rate is above the target exploitation rate of 46% but below the overfishing exploitation rate (also termed threshold exploitation rate) of 0.53. Managers within the Chesapeake Bay jurisdictions have the benefit of a control rule, whereby annual estimates of abundance, as well as exploitation rates, are referenced against empirical and model-based standards, respectively, to guide management efforts. One standard is the overfished threshold, equal to an annual percentage removal rate of 53%. Current scientific advice indicates that it will take several years of maintaining an exploitation rate on blue crab at or near the target exploitation rate (0.46) to increase the spawning potential to 20% of an un-fished stock. The 20% spawning potential is the goal of both the Chesapeake Bay Commission’s Bi-State Blue Crab Committee and the NOAA-sponsored Chesapeake Bay Stock Assessment Committee.

The Chesapeake Bay Commission’s Bi-State Blue Crab Technical Advisory Committee (BBTAC) released an August 2006 report, “Blue Crab2005, Status of the Chesapeake Population and its Fisheries” that presents the findings advice, following the 2005 crabbing season and the 2005-2006 winter dredge survey. The report states that 2005 can be reported as a slightly above average year in nearly a decade of low abundance. The lower stock levels of the winter dredge survey in 2005-2006 offer a preliminary indication that modest improvements seen in 2005 may not mean the beginning of a long-term trend. “Cautious management should continue.” That was sound advice, as the 2006 abundance of exploitable crabs was slightly higher than in 2005, but the harvest or exploitation rate also increased in 2006.

More recently, the 2007 Chesapeake Bay Blue Crab Advisory Report, prepared by the Chesapeake Bay Stock Assessment Committee (CBSAC), and provided below, compared the current status of the blue crab stock to thresholds and targets defined by the control rule initiated by the stock assessment of 2005. Stock abundance in 2006 was greater than the overfished threshold (an empirically observed minimum level of abundance thought necessary for stock maintenance). The exploitation rate or harvest rate, defined as the proportion of the legal-sized crabs available at the beginning of the year that were harvested during the year increased from 36% in 2005 to 50% in 2006. Low abundance, especially of recruits (within-year production), combined with an extended period of high exploitation rates, indicate a stock condition that warrants concern for the tenth consecutive year.