Development of Survey Methods to Effectively Sample Juvenile Red Snapper along the Atlantic Coast of Florida

Abstract

Understanding of the early life history of Red Snapper Lutjanus campechanus throughout the U.S. Atlantic Ocean (hereafter, “Atlantic”) is limited, in part, due to the paucity of juveniles (<150 mm TL) collected in long‐term fishery‐independent surveys in the region. This is in sharp contrast to the Gulf of Mexico (hereafter, “Gulf”), where juvenile Red Snapper have been consistently collected in surveys. This apparent regional disparity is poorly understood. Red Snapper nursery habitats may differ between the Atlantic and the Gulf, previous Atlantic surveys may not have included important nursery habitat, or sampling gear used in the Atlantic may not be effective at collecting juveniles. A 2‐year fishery‐independent study was conducted along the Atlantic coast of Florida to test whether juvenile Red Snapper could be effectively sampled with two types of gear not commonly used there: a semi‐balloon trawl like those used in long‐term groundfish surveys in the Gulf and small‐mesh Z‐traps. In total, 194 Red Snapper were collected in the trawl samples and 202 Red Snapper were collected in the Z‐trap samples—mostly juveniles (age 0 and age 1) captured in nearshore waters (<30 m deep). Like the Gulf, shallow coastal waters in the Atlantic likely function as nursery habitat for Red Snapper. Primarily small age‐0 Red Snapper were collected during trawl sampling, which targeted unconsolidated nonreef habitats, whereas larger age‐0 and age‐1 and older Red Snapper were collected during trap sampling, which targeted hard‐bottom reef habitats. Although this study represents the most successful sampling of juvenile Red Snapper in the Atlantic to date, further research is required to delineate the northern and southern extents of Red Snapper nursery grounds. Nevertheless, our results provide a framework for developing a fishery‐independent survey that targets juvenile Red Snapper in the Atlantic to provide valuable data for quantifying recruitment and monitoring the status and recovery of this economically important species.

Fishery management strategies for Red Snapper in the southeastern U.S. Atlantic: A spatial population model to compare approaches

“…For our Red Snapper case study, we set h = 0.99 to approximate a mean recruitment model in which recruitment is independent of spawning biomass as was used in the stock assessment (SEDAR 2021). Recruits to the system were distributed to nearshore areas (i = {1, 2, 3}) only, given the evidence that young Red Snapper (age-0 and age-1 fish) are primarily found in shallower water (Mitchell et al 2014;Powers et al 2018;Brodie et al 2022).…”

Increased fishery-independent sampling effort results in improved population estimates for multiple target species

“…While increasing survey effort may be predicted to result in equivalent or improved estimates of relative abundance over surveys with lower effort, this assumption should be examined on a case-by-case basis to determine appropriate actions. Retrospective analysis provides a means to assess potential biases and ascertain the most appropriate method of employing each single-species index of relative abundance for management decision-making, with options including statistical correction to ensure continuity of the data or breaking the time series, effectively excluding historical data (Brodie et al, 2022;Zimney and Smart, 2022). The decision for appropriate incorporation of an index of relative abundance may vary by species, depending on distribution, habitat use, or behavior (Brodie et al, 2022;Zimney and Smart, 2022).…”

“…Retrospective analysis provides a means to assess potential biases and ascertain the most appropriate method of employing each single-species index of relative abundance for management decision-making, with options including statistical correction to ensure continuity of the data or breaking the time series, effectively excluding historical data (Brodie et al, 2022;Zimney and Smart, 2022). The decision for appropriate incorporation of an index of relative abundance may vary by species, depending on distribution, habitat use, or behavior (Brodie et al, 2022;Zimney and Smart, 2022). Because the length of the time series is essential for understanding current population levels in relation to long-term trends, care must be taken and a variety of factors must be weighed, before a decision is made.…”