Some Studies on the New Zealand Oysters
[Introduction]
Despite the economic importance of the New Zealand mud-oyster, there has been little previous work on this animal, other than that of systematic accounts. A one-day survey of a Foveaux Strait oyster-bed carried out by Fleming (1952) resulted in a list of animals associated with the oyster-bed, and this list was then compared with other animal communities of Auckland Harbour and with Pliocene shell beds. Powell (1957) referred to the breeding habits of the mud-oyster, suggesting that they were similar to those of the oviparous Auckland rock-oyster. Further mention of the mud-oyster has been made by Korringa (1941, p. 7), Orton (1937, p. 93), and Roughley (1933, p. 281), who have listed it for the purpose of comparison with other species. Korringa, Orton and Roughley in their lists of incubatory and larviparous oysters refer to the New Zealand mud-oyster as Ostrea lutaria. Thus at the commencement of this study there were conflicting opinions regarding the type of larval development and nothing had been published on the anatomy of the soft-parts or reproduction.
This paper is primarily concerned with the systematic status, reproduction and development of the mud-oyster. Considerable difficulty was experienced in determining the status of this oyster and it was necessary to investigate the systematic status of all the known New Zealand oysters, before a decision was reached. The anatomy of the mud-oyster is essentially typical of the genus Ostrea.