Genetic monitoring for spawning ecology of captive Yellowfin Tuna (Thunnus albacares) using mitochondrial DNA variation. Aquaculture 218:387–395

Abstract

Abstract Mitochondrial DNA genotypes of captive broodstock of yellowfin tuna (Thunnus albacares) were compared with those of their offspring in order to monitor spawning frequency and periodicity. Among 38 broodstock individuals, 27 genotypes were observed, 18 of which established a single individual's identity. Spawned eggs and hatched larvae were collected on 48 sampling days over a period of 1 year. Among 538 eggs and larvae analyzed, 10 genotypes were observed; eight of them established a single female's identity, and two types were shared by two females. The spawning profiles of these females were determined by observing the occurrence of these genotypes in the offspring. Based on the dates when genotypes first occurred and on growth trajectories estimated for individual fish, the size of a female at first spawning was estimated to be 12 -28 kg and 75 -112 cm. Usually, multiple females spawned on a given date. The same genotypes were observed on almost any sampling day throughout the year. The results indicated that some individual females were capable of spawning almost daily for extended periods of time as long as they remained in the appropriate range of water temperatures and had sufficient food. Crown Copyright D 2003 Published by Elsevier Science B.V. All rights reserved