| Summary: | Freshwater eels are one of the world's most valuable cultured fish species. Although almost all worldwide eel production is derived from eel farms, no cultured eels are produced in New Zealand. Currently, the entire eel business in this country consists of catching shortfin (Anguilla australis) and longfin (A. dieffenbachii) in the wild and selling them on the local or international markets. However, changes in market specifications, production technology and wild eel stock restrictions have motivated an evaluation of culturing eels as a commercial route to contribute to regional economic development in New Zealand. This thesis describes a series of feeding trials that aim to show how to add value to the native New Zealand shortfin eel by developing a market-oriented eel product through aquaculture, and to provide a better understanding of some eel culturing strategies that may help improve fish production and reduce the eel-farm operational work. All trials were undertaken indoors in recirculation aquaculture systems (RAS) and fish were fed commercial pelleted feed. Most of these experiments were developed on yellow shortfin eel at the Aquaculture Laboratory of the AUT University, but one experiment on feeding stimulants was done at the Unitat de Cultius Experimentals (IRTA, Centre de Sant Carles de la Ràpita, Spain) on glass eel and elvers of the European eel, because of the resources needed. The main outcomes of this thesis are: (1) The development of a New Zealand eel product aligned with international market specifications on the fat content. It was possible to grow a fatty shortfin-eel product with 20 to 22% total fat starting from wild yellow eels with an initial fat content below 7%. From a human dietary perspective, the fat quality of the eel product obtained by culturing was appreciably superior (higher proportion of omega-3 fatty acids) than the fat of eels caught in the wild. (2) The achievement of good values of mean growth rate (SGR= 1.1% day-1) and feed conversion ratio (FCR ≤ 1.1) for rearing ...
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