Bioenergetics of captive Pacifi cb luefi nt una (Thunnus orientalis)

article i nfo Tuna bioenergetics can be described bythe followingrelationship: theenergyavailable for growth isequaltothe food energy minus all metabolic costs. These costs include routine metabolic rate, specific dynamic action, in- creased activity level, eliminated waste, and gonadal development. Captive populations of Pacifi cb luefin tuna (Thunnus orientalis) were held at ~20 °C in fiberglass tanks and fed on a regular schedule with a diet formulated to achieve an energetic content of 176 ± 36 kJ · kg −1 of biomass · day −1 (mean ± s.d.). To conduct a bioenergetic study, growth rates during the captive period and tissue energy values post-mortem were empiri- cally determined. Daily growth rates were obtained from a von Bertalanffy growth function based on curved fork length (CFL) measurements of live fish and post-mortem morphometrics. The parameters obtained for the captive bluefin growth function were 225.13 cm straight fork length (SFL), 0.173, and −0.497 years for L∞, k, and to, respectively. The growth equation, SFL = 225.13 · (1 −e (−0.173(t-(−0.497))) ) in conjunction with the