Reproductive status and body condition of Atlantic bluefin tuna in the Gulf of Maine, 2000–2002

The reproductive status and body condition of 195 (‡185 cm curved fork length, CFL; assigned age 7 and above) Atlantic bluefin tuna were assessed in the Gulf of Maine during the commercial fishing season of June– October, 2000–2002. Given the distance between known spawning and feeding grounds, the prevailing paradigm for Atlantic bluefin tuna (Thunnus thynnus thynnus, L.) suggests that the most likely histological state for females arriving in the Gulf of Maine after spawning would be a resting or quiescent state with little or no perigonadal fat. Alternatively, the presence of mature or mature-inactive histological states in some females supports a more varied or individualistic model for bluefin reproduction. No relationship was found between body condition and reproductive status. Males were found in all reproductive stages, but were more likely to be in spawning condition (stages 4 and 5) or a mature-inactive state (stage 6) in June and July. Female bluefin tuna were found in stage 1 (immature or non-spawning) and stage 6 (mature-inactive). Stage 6 females were only present in June and July and smaller females (<235 cm CFL) were more likely to be in stage 6 than large females (>235 cm CFL) sampled during those same months. The presence of smaller females in stage 6 arriving at the same time as larger females in stage 1 indicates that Western Atlantic bluefin tuna may have an asynchronous reproductive schedule and may mature at a smaller size than the currently accepted paradigm suggests.