By Dr. Ted Switzer
The Southeast Data, Assessment, and Review (SEDAR) is the cooperative process by which stock assessments of federally-managed species are conducted in the Southeast Region of NOAA Fisheries. SEDAR was initiated to improve planning and coordination of stock assessment activities and to improve the quality and reliability of stock assessments. SEDAR strives to provide an open and transparent approach for development and review of the scientific information on fish stocks that is critical to effective management and decision making, and includes participants from various sectors, including researchers, stock assessment scientists, managers, and stakeholders.
Many research groups at the institute provide data critical to the SEDAR process, including data on landings and discards from the commercial and recreational fishery, discard mortality, and life history including age and growth, reproduction, and stock identification. Data provided by the FIM program typically include trends in relative abundance through identification. Data provided by the FIM program typically include trends in relative abundance through time as well as annual estimates of size/age composition. Because these data are meant to characterize fluctuations in managed fish populations through time, several years of data are often required before fishery-independent indices become useful. Nevertheless, FIM data are increasingly being used for the assessment of managed fishes, including the ongoing SEDAR 51: Gulf of Mexico Gray Snapper.
Data from long-term seine-surveys (initiated in 1996 – 1998, depending on estuary) and recently-implemented polyhaline seagrass seine and trawl surveys (initiated in 2008) were analyzed separately to generate indices of abundance for age-0 (≤ 100 mm SL) and age-1 (101 – 250 mm SL) Gray Snapper; a single index was developed for each by combining data from multiple estuarine systems. In general, indices for each age class were similar between surveys (Figure 1); index results documented strong interannual variability in age-0 recruitment, but a generally increasing trend in the relative abundance of age-1 Gray Snapper. Although the SEDAR Data Workshop recommended incorporation of the long-term index only to avoid duplication, future efforts to incorporate data fromboth surveys into unified age-0 and age-1 indices should dramatically increase the statistical power of these indices.
In addition, data from the FWRI video survey off Tampa Bay and Charlotte Harbor were analyzed to generate and index of abundance for subadult/adult Gray Snapper (generally ≥ 300 mm FL) from 2010 – 2015. Model results generally corroborate the increasing trend in abundance of Gray Snapper in recent years. Although useful, this model was ultimately not recommended for incorporation, as an additional model, it was developed utilizing data from FWRI, NMFS – Panama City, and NMFS – Pascagoula video surveys.