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Blue Crab - Fact Sheet

Press Release

This is a summary of blue crab regulatory proposals submitted by Fisheries Service on April 21, 2008. Consult the Maryland Register, Code of Maryland Regulations and Natural Resources Article of the Annotated Code of Maryland for full legal text. Scheduled Publication Date: May 23, 2008.

The purpose of this regulatory proposal – proposed pursuant to the Maryland Department of Natural Resources’ management authority under Section 4-215(g) of the Natural Resources Article and its regulatory authority under Section 4-803(a) of the Natural Resources Article – is to limit the harvest of female blue crabs in order to rebuild the blue crab population by increasing the number of female crabs of spawning age.  These regulations are proposed now for four primary reasons: 

  1. The harvest of blue crabs in Chesapeake Bay has reached record low levels.  The 2007 Maryland harvest of approximately 22 million pounds was among the lowest recorded since 1945.
  1. Despite the low 2007 harvest and a persistently low crab population, the 2007 exploitation rate substantially exceeded the target removal rate.  A bay-wide target removal rate has been set at 46%.  In 2007 crabbers removed approximately 60% of the available crabs.
  1. In 2007, reproduction was extremely poor, placing the resource and the fishery in an increasingly perilous position.  When the abundance of these adult crabs is low, the population and the fishery are heavily dependent upon annual reproduction.  In 2008 the abundance of adult (reproductive-age) blue crabs was 120 million crabs.  This is the fourth lowest level measured since 1990, and is only slightly above the established minimum safe threshold of 86 million reproductive-age crabs.
  1. In January 2008, the Chesapeake Bay Stock Assessment Committee (the “CBSAC”), facilitated by the NOAA Chesapeake Bay Office, established a target of 200 million adult crabs for rebuilding the crab population.  The CBSAC recommended that the jurisdictions (Maryland, Virginia and the Potomac River Fisheries Commission) take action to achieve this target, and stated that management actions extending additional protection to female crabs will create the best odds of increasing the abundance of young crabs.   

In this light, and based upon extensive scientific evidence, Maryland, the Commonwealth of Virginia, and the Potomac River Fisheries Commission have worked closely in 2008 to coordinate Bay-wide blue crab conservation measures.  This historic level of cooperation among the jurisdictions provides a significant opportunity to effect positive change for the blue crab resource.

Background on Blue Crab Abundance

The blue crab is an iconic symbol of Chesapeake Bay and is a source of rich cultural heritage in the region.  In addition to being an essential component of the Chesapeake Bay ecosystem, the blue crab supports one of the last major commercial fisheries in the Bay and provides the economic foundation for many small Bay-side communities.  For these reasons, among others, DNR is committed to ensuring that the blue crab resource is protected so that it can continue to support sustainable fisheries for future generations, while fulfilling its ecological role within the Bay.

The Chesapeake Bay blue crab fishery is one of the few fisheries in the world where there is a precise estimate of available abundance each year.  The abundance of blue crabs in Chesapeake Bay has been measured annually since 1990 through the Bay-wide winter dredge survey (the “WDS”).  This survey is conducted from December through March each year, and is a cooperative effort between the Maryland Department of Natural Resources and the Virginia Institute of Marine Science.  The survey deploys dredge gear to sample approximately 1,500 sites from Poole’s Island near Baltimore south to the mouth of the Bay.  The survey is based upon a scientifically peer-reviewed design, and provides precise estimates each year of the number of crabs over-wintering in the Bay.  Crabs sampled in the survey are divided into two age groups:  (a) age 0 (young-of-the-year crabs), which represents the annual reproduction, and (b) adult, reproductive-age crabs, which represent the spawning population. 

Data from the annual WDS estimates establish that between 1990 and 1999 the total abundance of blue crab in the Chesapeake Bay declined by 61% (from 791 million crabs in 1990 to 308 million crabs in 1999).  Since 2000, total crab abundance has persisted at historically low levels.  The 2008 WDS estimated that there are 280 million crabs present in Chesapeake Bay, with the abundance of adult spawning crabs estimated to be 120 million crabs.  This is slightly lower than the 2007 estimate of 143 million adult crabs, 70% lower than levels observed in the early 1990’s, and substantially lower than the target abundance of 200 million.  The abundance of age 0 crabs increased slightly in 2008 to 163 million crabs, but is below the average level for the survey of 246 million crabs. 

The dramatic decline in blue crab abundance in the Bay, as established by the annual WDS, is attributable to many factors.  These factors include, but are not limited to, over-fishing, poor water quality, loss of key habitat such as submerged aquatic vegetation and oyster reefs, and changing climatic conditions that potentially limit the ability of young crabs to return to Chesapeake Bay after developing in the waters of the near-shore Atlantic.  As mentioned, if the abundance of the adult, reproductive-age portion of the population drops below the level of 86 million, the fishery will likely become unsustainable because the population will be unable to adequately reproduce. 

Management of the Chesapeake Bay Blue Crab Fishery

In 2000, Maryland and Virginia reached consensus on a framework for managing a sustainable Bay-wide blue crab fishery.  This framework is known as a control rule, and was adopted by the Chesapeake Bay Commission’s Bi-State Blue Crab Advisory Committee in 2001.  The control rule was updated in the 2005 stock assessment of Chesapeake Bay blue crabs.   The control rule sets an exceedance threshold of 53% for sustainable annual fishery removals.  In other words, no more than 53% of the total blue crab population should be removed in any given year.  In order to create a margin of safety to account for uncontrollable variances in fishery removals, the control rule sets a target annual removal of 46% of the population.  If the blue crab fisheries (commercial and recreational) remove, on average, 46% of the total population annually, the data shows that the abundance of crabs will likely remain sufficient to ensure healthy reproduction and support a healthy fishery.  Conversely, if removals consistently exceed the 46% target level and frequently exceed the threshold level of 53%, blue crab abundance will likely decrease to levels that are too low to sustain healthy reproduction and a healthy fishery. 

Each year the percentage of crabs removed from the Bay-wide crab population is calculated and compared to the established threshold and target levels of 53% and 46%.  The percentage removal is calculated by dividing the number of crabs harvested Bay-wide between April 1st and January 31st by the estimated total abundance from the preceding year’s WDS.  Harvest levels are estimated from commercial harvester reports in Maryland, Virginia and the Potomac River.  In 2007, it was estimated that the fishery harvested 60% of the total crab population. 

A Plan for Rebuilding Crab Abundance

The Bay-wide plan for rebuilding blue crab focuses upon the primary objective of maintaining annual removals of blue crab at the 46% target level in order to achieve, within the near-future, the target abundance of 200 million adult crabs.  An adult crab population at the target abundance of 200 million or greater is more likely to produce a robust year-class of young crabs when environmental conditions are favorable, and will sustain harvests that are substantially higher than those realized between the years 2000 and 2007.  While the time necessary to rebuild the crab population to the target adult abundance of 200 million cannot be estimated with certainty, analyses have shown that if fishery removals are constrained to the target level of 46% or lower, the probability of achieving the target abundance within 5 years is significantly greater than if the removal rate consistently exceeds the threshold level of 53%.

Estimating the Appropriate Reduction for the 2008 Harvest

Since 1990, annual estimates of crab abundance generated by the WDS have proven to be excellent predictors of the subsequent year’s harvest.  Indeed, between 1990 and 2007 the actual harvest has, on average, fallen within 9 percent of the predicted harvest.  As such, the annual estimate of abundance from the WDS provides the management jurisdictions with a reliable tool to not only  project the upcoming Bay-wide harvest, but also to estimate what the target Bay-wide harvest should be in order to achieve the 46% target removal level.  The difference between the projected harvest and the target harvest represents the degree to which the upcoming harvest should be constrained in order to meet the 46% target removal.  For 2008, the projected harvest is approximately 46 million pounds based upon a total abundance (adult plus age-0 crabs) of 280 million crabs.  The target harvest to achieve the 46% removal target is approximately 38 million pounds.  Therefore, the projected harvest of 46 million pounds needs to be reduced by 17% Bay-wide.  Since management actions will be confined to the female component of the harvest (which is approximately half of the Bay-wide harvest) in order to achieve a maximum increase in the spawning stock, the Bay-wide reduction in female harvest during 2008 should therefore be approximately 34%.

Regulatory Action

In conjunction with new management measures in Virginia, the Department has designed these regulatory actions based upon reliable management calculations that predict a 34% reduction in the 2008 harvest of female blue crabs through a combination of enforceable and measurable management measures.  Going forward from 2008, the Department is committed to maintaining the annual target fishery removal fraction of 46% of the total abundance.  For this reason, DNR anticipates adjusting regulations each year as necessary following receipt of the results of the annual WDS.   

Emergency Proposal

The proposed action will prohibit all recreational harvesting of females, with the exception of female soft crabs (which, once caught and discarded, are likely to die). If adopted early in the crabbing season, this action will provide a 3 % reduction in female harvest. If adopted early in the crabbing season, this action will provide a 3 % reduction in female harvest. The proposed action will prohibit the commercial harvesting of female crabs after October 22. This season closure will provide a 19 % reduction in female harvest. In addition, prior to the closure of the commercial season after October 22, the female harvest will be controlled through bushel limits for licensed commercial crabbers for the period of September 1 through October 22. In addition, prior to the closure of the commercial season after October 22, the female harvest will be controlled through bushel limits for licensed commercial crabbers for the period of September 1 through October 22.  Bushel limits will be established based upon the individual commercial crabber’s average reported daily harvest of females during September and October in the years 2004 through 2007. If adopted early in the crabbing season, the Department predicts that the recreational prohibition will provide a 3% reduction in the female harvest, the closure of the commercial season after October 22 will provide a 19% reduction, and the bushel limits in September and October will provide a 12% reduction.

The Department has calculated tiered bushel limits for September 1 though October 22 in order to ease the economic burden on the small fraction of commercial crabbers who have historically realized highest catches of mature female crabs during the fall season.  In the years 2004-2007, only 1.6% of licensed crabbers realized an average daily catch of greater than 40 bushels of females per day during the month of October.  Approximately 83% of these crabbers reside in Dorchester County.  By contrast, 90% of licensed commercial crabbers in Maryland realized an average daily catch in October of less than 10 bushels of females.  The Department has determined that by grouping crabbers into catch categories based upon their reported catch history and applying limits to each catch category, the total catch can be significantly reduced without a disproportionate economic burden being born by those that have historically realized the heaviest catch.

Historically, catch rates for mature female crabs are highest during the month of October when the female migration peaks.  The catch categories and associated bushel limits will therefore differ between September and October.  The catch categories and approximate associated bushel limits for September and October are:



Finally, the Department is proposing to modify the target number of Limited Crab Catcher (LCC) licenses at the current number of issued licenses. Current licensees will not be affected by this action. The proposed action will reduce the number of LCC licenses available to the current level in order to prevent an increase in commercial fishing effort.  The proposed action will also establish a Management Control Date of December 16, 2007. Participation by any individual in the blue crab fishery, after the control date, will not be considered in the calculation or distribution of crabbing rights should further entry limitations be established in the future.   Conversely, harvest data constrained by 2008 regulations will not adversely affect an individual’s catch history for purposes of future allocation decisions.

Permanent (Non-Emergency) Proposal

The Department intends, in accordance with the law, to move forward with a non-emergency regulatory package if the Administrative, Executive, Legislative and Regulatory Committee does not approve the emergency regulations.   This proposed action is significantly different than the emergency regulatory proposal, though both are designed to achieve the goal of a 34% reduction in the female harvest.  The non-emergency alternative principally includes: (i) a prohibition on commercial harvesting of females crabs after October 10, and (ii) a prohibition against all recreational harvesting of females, with the exception of female soft crabs (which, once caught and discarded, are likely to die).  As with the emergency proposal, under the non-emergency proposal the Department proposes to modify the target number of Limited Crab Catcher (LCC) licenses at the current number of issued licenses, and to establish a Management Control Date of December 16, 2007.

The Department believes that the emergency proposal, as compared with the non-emergency proposal, will significantly mitigate the economic burden of the reduced harvest by delaying the season closure on female crabs until after October 22 through applying female bushel limits on September 1.  The Department has calculated that should the emergency regulations take effect, an immediate closure of the recreational harvest to female crabs will realize a full 3% reduction in the female harvest, and substantially more of a reduction than what would be realized should the recreational closure not occur until after this non-emergency proposal goes into effect.  Consequently, the non-emergency proposal places a heavier burden upon the commercial harvesters and therefore results in an earlier closure of the season to female crabs.  If the emergency proposal is in effect in time to realize the full 3% reduction in female harvest from the recreational fishery, than this non-emergency proposal will be withdrawn.

Public Participation and Input

In conjunction with developing preliminary management ideas and options for increasing the spawning capacity of the Bay’s blue crabs, in February and March the Department held seven public meetings on the matter.  These meetings included participation by the Tidal and Sport Fisheries Advisory Commissions, the Smith Island Waterman's Association, Chesapeake Bay Seafood Industries Association, and Sport Crabbers of Baltimore County. During this same time, the Department also received over 550 public comments on preliminary ideas and options through the Department’s web site, by phone, and through correspondence. 
On April 9, 2008, the Department posted revised draft management options on its web site, which included a number of potential options, including ones similar in concept to the ones proposed here.  On April 10, 2008, the Department held a public hearing on the draft management options.  Based upon public comment from this meeting and from public correspondence on the matter, the Department refined the bushel limit options so as not to disproportionably impact the historic heavy harvesters noted above. The primary change to the proposal was the replacement of a flat 20 bushel per day limit applicable to the entire population of licensed crabbers with no regard to catch history, with the tiered bushel limits outlined above. 
Following the April 10, 2008 meeting, the commercial crabbing industry provided the Department with an alternative proposal for reducing the female crab harvest in 2008 that included the following collective measure:  (1) creation of a crab sanctuary delineated by the Bay’s 35-foot depth contour so that crab harvest would be prohibited all year in waters deeper than 35 feet; (2) shortening of the season so that crabbing would begin 2 weeks later and end 2 weeks earlier than as established by current regulation; (3) establishment of bushel limits in Maryland to match those in Virginia; and, (4) a mandate that all escape or ‘cull’ rings on crab pots be open for the duration of the season to permit the escapement of small peeler and hard crabs. 
The Department has reviewed the industry’s collective proposal in context with the established goal of reducing female harvest by 34% through management options that are enforceable, measurable, and reliable, and has concluded the proposal is deficient on a number of levels.  Regarding the crab sanctuary element of the proposal, data supportive of the effectiveness of such a crab sanctuary is extremely limited given, among other things, that studies have shown that very little harvesting has historically occurred in waters deeper than 35 feet, and communication with the Department’s Natural Resources Police indicate that enforceability of an effective sanctuary strategy is problematic.  Shortening the season by 2 weeks on either end will have limited conservation benefit given that historically the two weeks in April and the two weeks in December that the industry proposed to eliminate have resulted, combined, in only about 1% of the total female harvest.  Similarly, establishing bushel limits comparable to Virginia’s – a daily limit of 51 bushels of females through May 31, and no limits thereafter – will have little or no conservation benefit for mature female crabs.  Finally, while requiring culling rings on crab pots could prove a valuable mechanism for constraining the peeler crab fishery, under Section 4-803(b)(3) of the Natural Resources Article, the Department is presently prohibited from implementing such regulations.

The Department will hold a public hearing on this regulatory proposal at 6:30 p.m. on May 7, 2008 in Governor’s Hall at Sailwinds Park in Cambridge, Maryland.  The June 4th meeting in Annapolis has been canceled

Principle Foundational Documentation

            The Chesapeake Bay Stock Assessment Committee. National Oceanographic and Atmospheric Administration, Chesapeake Bay Office (NCBO).  2008. Final Summary of a Working Meeting on Blue Crab Assessment and Management. Annapolis, Md.  3p.

                Bi-State Blue Crab Advisory Committee.  2001.  Taking Action for the Blue Crab: Managing and Protecting the Stock and its Fisheries.  A report to the Chesapeake Bay Commission; Annapolis, Md, Richmond , Va. 24p.

            Miller, T. J. et al. 2005. Stock Assessment of the Blue Crab in Chesapeake Bay. Technical Report Series No. TS-487-05 of the University of Maryland Center for Environmental Science, 162p.

            Sharov, A. F., J. H. Volstad, G. R. Davis, B. K. Davis, R. N. Lipcius, and M. M. Montane. 2003. Abundance and exploitation rate of the blue crab (Callinectes sapidus) in Chesapeake Bay. Bulletin of Marine Science 72:543-565.