Abstract:
Spiny lobsters are a valuable fishery worldwide. In New Zealand they are worth $120 million a year in exports, as well as being readily sort after by recreational fisherman. They are exceptional in having a very long larval stage of approximately two years, which is spent in the open ocean, making it difficult to study and understand this crucial link in the life cycle. In particular, very little is known about what the larvae feed on. Identifying the main prey items of lobster larvae has the potential to provide a better understanding of recruitment processes, essential for fisheries management. Larval diet has also proved a major stumbling block for aquaculture of these species, which could provide a boost to the New Zealand economy. With the recent advances in molecular genetics techniques, powerful new tools were available to identify the tiny gut contents of lobster larvae and gain an understanding of their natural diet. These techniques are not without issues. Overcame the problems of contamination by host DNA, DNA degradation were some of the issues coming into this study, these were addressed and overcome in vitro using DNA from adult tissue. Primers for experimental prey were designed, these techniques were used to identify known prey from the guts of experimentally fed phyllosoma grown in culture. DNA sequences were obtained from a variety of zooplankton caught in association with phyllosoma. These sequences were used along with sequences from GenBank to design a range of taxon-specific primers. These primers were tested to be successful at amplifying DNA from the taxa they were designed for and also to not amplify lobster DNA which makes them suitable for use on the DNA from the guts of wild phyllosoma to identify prey. Identified Cnidaria, Gadiforme, Gastropod and Crustacean DNA as diet items of wild phyllosoma, these taxa fit in with previous studies with these taxa possessing the characteristics that makes them suitable prey of phyllosoma. These taxa were also identified in past molecular diet studies on related Panilurid phyllosoma These taxa identified provide new information for the diet of J. edwardsii as these were the first results of a molecular diet study on this species. The information obtained in this study can be incorporated into nutritional studies to find the nutritional components of the taxa identified which can be used to develop an artificial feed for use in aquaculture of spiny lobsters.