Temperature Affects Growth and Tissue Fatty Acid Composition of Juvenile Atlantic Spadefish

The Atlantic spadefish Chaetodipterus faber holds potential as an aquaculture species, but successful intensive production of this species will depend on the identification of proper husbandry methods, including the use of optimal water temperatures. Accordingly, we evaluated the growth performance and tissue composition of juveniles (37.8 ± 0.5 g [mean ± SE]) reared at 20, 25, or 30°C in indoor recirculation systems (three 100‐L tanks per temperature, five fish per tank) for 8 weeks. Weight gain, specific growth rate, feed conversion ratio, and feed intake were significantly affected by water temperature, and increasing temperature yielded greater feed intake and growth rates as well as lower feed conversion values. Although performance observed at 25°C was statistically similar, growth and growth efficiency were nonetheless marginally superior within the 30°C treatment group. Fish exhibited differences in the fatty acid composition of neutral and polar lipid fractions of gill and muscle tissue that were broadly consistent with homeoviscous adaptation to cooler or warmer water temperatures; specifically, increasing proportions of unsaturated and longer‐chain fatty acids were observed in fish from cooler water temperatures. This suggests that unsaturates, particularly long‐chain polyunsaturated fatty acids that are associated with maximum membrane fluidity at cold temperatures, are critical in the diet of Atlantic spadefish depending on culture conditions.