Evaluating the Relative Impacts of the Recreational and Commercial Sectors of the Blue Crab Fishery in Maryland
Principal Investigator:Anson H. Hines
Institution:Smithsonian Environmental Research Center
Co-Principal investigator:Matthew B. Ogburn, Smithsonian Environmental Research Center; Eric G. Johnson, University of North Florida, Department of Biology
The blue crab, Callinectes sapidus, is perhaps the Chesapeake Bay's most iconic species, supporting the Bay's most lucrative commercial fishery and a thriving recreational fishery. The fishery is complex, with multiple management jurisdictions, regional and seasonal variation in fishing gear and effort, and a variety of markets. In stock assessment models used for fishery management, recreational harvest is estimated to be 8% of commercial harvest, but this estimate is outdated and was based on highly variable estimates of recreational fishing. Thus, the primary objective of the proposed study is to generate scientifically-rigorous estimates of recreational crab harvest for Maryland waters of the Chesapeake Bay.
Mark-recapture crab tagging techniques provide a scientifically-rigorous method for estimating relative exploitation rates by fishery sector which, in combination with commercial harvest reporting, can be used to determine regional and state-wide recreational harvest. The specific goals of the proposed mark-recapture study are (1) to provide measurements of exploitation rate by sector for harvestable female and male crabs for each commercial harvest reporting area, (2) to evaluate seasonal variability in recreational exploitation rates, (3) to estimate regional and state-wide recreational harvests by applying relative rates of commercial and recreational exploitation to commercial harvest reports within each reporting area, and (4) to document the current characteristics of the recreational sector using a survey of tag reporters.
In year 1, we plan to estimate regional exploitation rates by fishery sector within 15 of the 25 Bay reporting areas during the time of peak exploitation (summer/fall). This will be done by tagging 400 male and female crabs (100 in each of 4 sites per area) from the legal fishable stock in each area (60 release sites, 6,000 crabs total). Reporting areas will be chosen in coordination with MD DNR and MWA so that the 10 areas not directly studied will be paired with a comparable study area for estimation of relative exploitation in those areas. In year 2, we will conduct a detailed evaluation of temporal variation in recreational harvest by tagging 200 crabs in 3 representative regions (chosen based on year 1 results) each month from May-September (3,000 crabs tagged). We will rely on recreational and commercial watermen for recaptures of tagged crabs. High value reward tags ($50) will be used to correct for differences in reporting rate of standard value tags ($5) among fishery sectors. A mail-in survey will be sent to tag reporters to provide additional information including access type (public vs. private), gear type, capture location, and capture depth.
Recreational harvest and exploitation rates and other results generated from this study will be transmitted to management agencies through our representation on the Chesapeake Bay Stock Assessment Committee, the Chesapeake Bay Program Fisheries Goal Implementation Team, and through meetings with fishery managers. Results will be transmitted to watermen and the general public through presentations to the Maryland Watermen's Association and other interested groups, print and web media, and through SERC's regular education programs.