Introducing the Atlantic Croaker Micropogonias undulatus: an Emerging Candidate for Multiple Purpose Aquaculture Production

The Atlantic croaker Micropogonias undulatus is an emerging candidate for multiple purpose commercial aquaculture production including use as a baitfish, foodfish, and biological model. Historically, croakers have been a popular wild-caught foodfish that supported important commercial and recreational fisheries, but wild-stock declines due to over-fishing and incidental by-catch mortality from shrimp trawling, have decreased the fisheries potential. Atlantic croakers have long been studied as models of teleost reproductive endocrinology and for toxicology testing. Atlantic croakers are also preferred bait for popular recreational fishing species such as spotted seatrout Cynoscion nebulosus, grouper Epinephelous spp or Mycteroperca spp, tarpon Megalops atlanticus, and snook Centropomus undecimalis.

Atlantic croakers possess many favorable culture attributes for a marine culture species. Good juvenile growth (210 to 420% weight gain in 49 days) occurred during production studies from 25 to 30ºC. No observable decrease in feed intake at 21ºC indicates growth occurs over a wide temperature range. Juveniles are more tolerant of low temperatures than adults, but prolonged or sudden exposure to cold temperatures may cause mortalities. Lethal temperatures for juveniles (low 0.6ºC, high 38ºC) and adults (low 3.3ºC, high 36ºC) have been established. Juveniles may be capable of over-wintering in ponds in southern climates, while broodstock would need to be over-wintered indoors or in geothermally heated water. Atlantic croaker larvae and juveniles are adaptive to a broad range of salinities as well as rapid salinity changes. Adults require higher salinity and broodstock may be held at salinity ranges from 5 to 20 g/L, while juveniles may be raised in as little as 0 g/L salinity for short periods with 1 to 5 g/L being the optimal range for growth.

 Larval Atlantic croaker require special feeding with live cultured foods that may be produced using established protocols for production of red drum larvae. Preliminary studies indicate croaker juveniles require high protein (40-45%) and low to moderate lipid (5-8%) diets for the best growth. As with red drum culture, protein content of the diet can be decreased from 45% to 32% crude protein as the fish mature from larvae through growout.