Embryos, larvae, and early juvenile stages of the commercial scallop Pecten fumatus Reeve, were held at temperatures ranging from 13 to 27°C. An incubation temperature of 18°C produced the greatest percent development of D-veligers from eggs. The growth rate of larvae increased from 2.5 μm/day at 15°C to a peak of 6.5 μm/day at 24°C but decreased with a further increase in temperature to 27°C. Age-specific larval survival decreased significantly with increasing temperature in the range 15-27°C. However, size-specific survival, which is a more meaningful measure of optimal rearing temperature, exhibited a pronounced peak value at an intermediate temperature of 21°C. On the basis of these results, the maintenance of larval rearing temperatures between 18 and 21°C is likely to provide the maximum yield of pediveligers. The growth of 3-wk-old spat (mean shell height, 1.04 + 0.26 mm), held in the hatchery, increased from a negligible rate at 13°C to a maximum rate at 24°C. During the fifth and final week of the trial, a constraint to continued exponential growth became evident at all temperatures tested except 13°C. Survival and byssus attachment of spat were highest at temperatures supporting the highest growth rates. The use of byssus attachment as an indicator of favorable spat-growing conditions is discussed. Possible ecological implications of ontologic change in temperature optima are discussed in relation to variability in annual fisheries' catches. Occasions on which optimal temperature regimens for embryo development and larval and spat growth occur are rare in Jervis Bay, NSW. Aspects of El Nino Southern Oscillation events and the oceanography of southeastern Australia are discussed as a possible mechanism by which such regimens might occur.
|Number of pages||8|
|Journal||Journal of Shellfish Research|
|Publication status||Published - 1996|