THE POTENTIAL FOR DEVELOPING CONTROLLED BREEDING IN THE CHILEAN OYSTER

A.G. Jeffs, 1999

Aquaculture International, 7 (3): 189-199

Abstract:

International interest in the commercial aquaculture of the Chilean oyster, Tiostrea chilensis, is frustrated by an inability to artificially control their unusual breeding behaviour. The manipulation of breeding in this oyster will rely on a better understanding of its gametogenic cycle. Consequently, the gametogenesis of a wild population of highly fertile Chilean oysters from northern New Zealand was studied over 3 y to assess the potential for artificially controlling oyster breeding for aquaculture. The population was mostly comprised of simultaneous hermaphrodite oysters that generally followed annual cycles of gametogenesis. Oysters spawned as males throughout each year with increased spawning from November to February (ie., austral spring and summer). Ova were abundant throughout the year, although female spawning increased during spring. The unpredictable spawning of ova amoung individual oysters and the strong possibility of self-fertilization create difficulties for the development of controlled breeding in this species. If the full aquaculture potential of T. chilensis is to be realized, further research should be directed at identifying the factors involved in controlling female maturation, spawning and fertilization.

(Cawthron Institute, Private Bag 2, Nelson, New Zealand)

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