Evidence of positive influence of prolonged photophase on growth and survival during the larval rearing of yellow fin tuna (Thunnus albacares).

The yellowfin tuna, Thunnus albacares, is an important species in tuna fisheries worldwide. At the Inter-American Tropical Tuna Commission (IATTC) Achotines Laboratory in the Republic of Panama captive yellowfin broodstock tuna spawn regularly providing material for early life history studies (Wexler et al 2003; Margulies et al. 2007). Larval rearing of the species is extremely difficult with very low survival rates. Studies with other marine fish species suggest that prolonged photophase can improve the biological performance of the larvae. Although extended photophase was occasionally used at Achotines Laboratory to speed growth of cultured larval and juvenile tuna used in physiology and respirometry studies, no comparative trials of different photophase had been carried out.