Habitat-specific growth, survival and diet of late juvenile hatchery-reared spotted seatrout (Cynoscion nebulosus)

• Little is known about the late juvenile stage of spotted seatrout.
• Even less is known about how hatchery-reared (HR) fish adjust to natural conditions.
• Relative growth was better in SAV and shoreline habitats than in open water.
• Diets of late juvenile HR fish included prey types also consumed by wild fish.
• Vegetated and shoreline habitats favor late juvenile HR spotted seatrout.

As a key recreational fishery species throughout the Gulf of Mexico, the spotted seatrout (Cynoscion nebulosus Cuvier) requires sound management practices (VanderKooy and Muller, 2003; Fulford and Hendon, 2010). Accordingly, it is imperative to fully understand the ecology of spotted seatrout (Lorio and Perret, 1978), especially factors affecting the successful recruitment of this estuarine-dependent carnivore. Considering the large gap in knowledge about the ecology of late juvenile stage spotted seatrout, as well as the need to evaluate current stock enhancement practices for this species, the objective of this study was to assess the growth, survival and diet of late juvenile hatchery-reared (HR) spotted seatrout within three prospective nursery habitats in a shallow bay system: submerged aquatic vegetation (SAV), non-vegetated shoreline (NVS), and non-vegetated open water (NVO). While caged under natural conditions for 4 weeks, relative growth was significantly greater for fish caged in SAV and NVS habitats compared to NVO habitat. Mortality was relatively high in the first week of the study during acclimation. Stomachs of HR fish contained prey, and the diet composition of HR fish included common prey types consumed by comparable sizes of wild fish. Findings indicate that habitats within or in close proximity to SAV or marsh shoreline offer more favorable conditions than deeper open water habitat for late juvenile HR spotted seatrout. Moreover, HR fish can acclimate to natural conditions and successfully transition to a natural diet, in the absence of predators and competitors.