Recruitment of Juvenile Red Drum in North Carolina: Spatiotemporal Patterns of Year‐Class Strength and Validation of a Seine Survey

Abstract

AbstractSixteen years of data from a North Carolina Division of Marine Fisheries seining survey were analyzed to assess the validity of the survey, describe spatial and temporal patterns in recruitment of red drum Sciaenops ocellatus, and evaluate factors that potentially contribute to recruitment variation. Overall, 11,817 age‐0 red drum (total length = 11–104 mm) were collected in the survey during 1991–2006. Annual estimates of red drum recruitment were variable over time and showed no long‐term trend. The dome‐shaped catch‐per‐unit‐effort (CPUE) pattern of all annual cohorts indicated that the seine survey captured peak abundance levels each year; the spatial coverage of the survey also appeared to be adequate. Regional correlations within North Carolina were strongest for areas that were adjacent to one another, and the North Carolina statewide index was not correlated with indices from Florida or Texas, suggesting that factors controlling recruitment of red drum operate at a scale of tens to hundreds of kilometers. Age‐0 red drum were caught at temperatures ranging from 8.5°C to 33.5°C and at salinities from 0.0 to 34.7 practical salinity units (psu; 1 psu ≈ 1‰). A generalized additive model explained only 8.1% of the variation in age‐0 abundance, suggesting that early juvenile abundance cannot be predicted with these abiotic factors. Variation in loss rates of age‐0 red drum appeared to be independent of variation in cohort density. The CPUE of age‐0 red drum was correlated with harvest of age‐2 fish 2 years later, suggesting that additional modification of year‐class strength after the early juvenile stage is moderate or weak. Results of this study have improved our understanding of red drum recruitment patterns while simultaneously validating the seine survey.