Alexandria, VA – The Atlantic States Marine Fisheries Commission’s South Atlantic State/Federal Management Board approved the 2015 Black Drum Benchmark Stock Assessment and Peer Review Report for management use. Based on the assessment results, black drum is not overfished and not experiencing overfishing. Median biomass was estimated to have declined slowly and steadily from 135.2 million pounds in 1900 to 90.78 million pounds in 2012, though the median biomass estimate in 2012 is still well above the median biomass that produces maximum sustainable yield (BMSY; 47.26 million pounds). The median maximum sustainable yield (MSY) estimate is 2.12 million pounds and provides an annual catch target that can be used to sustainably manage the fishery. The median overfishing limit (OFL), which provides a catch threshold indicating when overfishing is occurring, is estimated to be 4.12 million pounds.
Black drum are a data-poor species. Their rarity and migratory patterns lead to highly variable levels of encounter in state surveys and fisheries. Further, limited size composition data has been collected, making the use of age-structured models unreliable. For these reasons, data-poor, catch-based modeling methods were used for the assessment. These models estimate reference points based on historical catch data and life history information.
Three modeling methods were evaluated to estimate catch reference points for assessing population health such as MSY and OFL. These methods included Depletion-Corrected Average Catch, Catch-MSY, and Depletion-Based Stock Reduction analysis (DB-SRA). These methods have been evaluated against data-rich assessments and are considered robust given inputs and assumptions are correct. DB-SRA was selected as the preferred method based on the underlying configuration of the methods, the required inputs, and performance of the methods evaluated through sensitivity analysis and simulated projections.
The Black Drum Stock Assessment Subcommittee noted the black drum stock assessment would be improved by applying a more complex, data-rich assessment method such as a statistical catch-at-age model. Data limitations that need to be addressed to successfully make this transition are biological sampling (length and age) of recreational and commercial fisheries and a fishery-independent survey tracking abundance and the age structure of the mature stock. Additionally, information about fish discarded in commercial fisheries and movement of fish would improve the assessment.
Under the Black Drum Fishery Management Plan (FMP), which was approved in 2013, states were required to implement a maximum possession limit and minimum size limit (of at least 12 inches) by January 1, 2014, with an additional increase of the minimum size limit to at least 14 inches required by January 1, 2016. The FMP also includes a management framework to adaptively respond to future concerns or changes in the fishery or population. Given the assessment findings, the Board choose to not make any additional changes to the management program at this time.
A more detailed description of the stock assessment results is available on the Commission’s website at http://www.asmfc.org/uploads/file/54d3a0462015BlackDrumAssessmentOverview_Feb2015.pdf.
The final assessment and peer review reports will be posted to the Commission website the week of February 9th, www.asmfc.org, on the Black Drum webpage. For more information on the Stock Assessment, please contact Jeff Kipp, Stock Assessment Scientist, at email@example.com; and for more information on black drum management, please contact Kirby Rootes-Murdy, FMP Coordinator, at firstname.lastname@example.org.