Developing broodstock resources for farmed marine fish

The expansion of New Zealand aquaculture will benefit from diversification into new high value finfish such as Yellowtail kingfish (Seriola lalandi) and Hapuku (groper, Polyprion oxygeneios). To ensure success, domesticated selected broodstock need to be established along with systems that can reliably produce high quality gametes and juveniles. Collections of wild Kingfish and Hapuku broodstock were completed by the National Institute of Water and Atmospheric Research from 2000 onwards. Over 100 wild broodstock have since been reared to establish the parental stocks. Wild females of both species are very fecund and millions of eggs have been produced each breeding season. One of the main challenges is to ensure that multiple parents contribute during spawning to create genetically variable, selected offspring (F1). Due to the current reliance on communal group spawning, multiplex microsatellite DNA marker panels were developed to determine the parentage of the resulting F1 progeny. Although F1 from multiple parents have been identified, some broodstock produced a disproportionate number of the progeny. This has highlighted the need to manage parental contribution to the F1, which would otherwise exclude many individuals from contributing to the gene pool. As a result we are developing techniques to control mating and to maximise the number of founding wild parents in the programme.