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Five test diets – 20, 10 rotifers/mL/d, 5 rotifers/mL/d + 3 nauplii/mL/d, 5 and 8 nauplii/mL/d – were used to examine the effect of Acartia tonsa nauplii and a small strain of rotifers on survival, myotome height, notochord length, and condition (myotome height/notochord length) of spotted seatrout, Cynoscion nebulosus, larvae through 6‐d posthatch (PH). Diet did not affect survival. Larvae fed 5 and 8 nauplii/mL or 5 rotifers + 3 nauplii were longer, taller, and in better condition than larvae fed either 10 or 20 rotifers/mL. The condition of larvae fed diets with nauplii declined after Day 5 which suggests a shortage of prey in those diets after Day 4 or 5. Although copepod nauplii offer substantial short‐term benefits in the culture of spotted seatrout, further study is required to determine the number of nauplii and/or rotifers necessary in the diet beyond Day 4 and to assess the long‐term impact of the different diets.

Culture models and facilities for large-scale, commercial production of popular Gulf of Mexico species are unavailable. The spotted seatrout (Cynoscion nebulosus) is one of the most popular recreational fishes in the Gulf of Mexico. Seatrout culture techniques were adapted from red drum (Sciaenops ocellatus) protocols developed in the 1970s. Broodstock husbandry, spawning, and extensive pond rearing techniques using fertilized and bloomed brackish ponds were well-established by the 1980s. By 2018, approximately 80 million 25-30-day old seatrout had been produced, mainly for stock enhancement. Cannibalism and poor nutrition hindered intensive tank culture. Between 2005 and 2015, an intensive tank-rearing protocol that reduced cannibalism and intracohort variability and increased average survival to almost 50% was developed using algal concentrate, rotifers, brine shrimp (Artemia sp.), and microencapsulated feeds. Preliminary results suggested that a 500 g fish could be produced in approximately 10 months. Nevertheless, interest in commercialization has remained low. Zootechnical performance throughout the latter stages of culture, the economics of production, consumer preferences/perceptions, and market capacity must be documented to complete the assessment of the spotted

Gametogenesis was monitored histologically in wild‐caught red snapper (Lutjanus campechanus, Poey) maintained in captivity under simulated natural photothermal conditions. Gonads were collected every 2–3 weeks (average n = 14) for histology during the pre‐spawning season (February to May, temperature increasing from 16°C to 24°C). Primary vitellogenic oocytes were first observed in one female when temperature reached 20°C. Subsequent samples revealed females in pre‐vitellogenesis or at early stages of vitellogenesis, although one female had tertiary vitellogenic (Vtg3) oocytes. The first histological signs of spermatogenesis were observed when temperature reached 17°C. Spermatozoa were observed in testicular lobules of all males sampled on 14 May (24°C) but little or no sperm was released during manual stripping. Ten males and 10 females were left in tanks and monitored for spawning. No egg release was observed during the monitoring period that encompassed the natural spawning season of wild red snapper. Ovarian biopsies taken during the late spawning season (16 July) revealed that four of eight sampled females had Vtg3 oocytes. Males were manually stripped but released no sperm. These results indicate that captive red snapper can complete gametogenesis in photothermal controlled systems. Additional research is needed to develop procedures that will achieve reliable maturation and spawning.

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