Publication Abstract

Temperature dependent development rates of plaice (Pleuronectes platessa L.) eggs from the Irish Sea

C. J. Fox, A. J. Geffen, R. Blyth and R. D. M. Nash

The development rates of Irish Sea plaice eggs were determined for temperatures between 6 - 12^oC. Differences in temperature dependent development rates were apparent when the results were compared with data in the literature derived from North Sea parental stock and widely used for estimating ages of eggs sampled in the field. Eggs from Irish Sea parental stock developed more rapidly and hatched up to two days earlier than North Sea eggs incubated at the same temperature. Asynchronous development was observed in individually monitored eggs but the variability observed was similar to that calculated from batch experiments. Because of the large number of parental crosses undertaken, variance estimates from the Irish Sea egg incubation experiments can now be included in AEPM for plaice in this region. In terms of parental effects, larger females produced significantly larger eggs although egg size decreased over successive batches from the same female. Temperature-dependent egg development rates were affected by egg size in a non-linear manner for eggs incubated at 6^oC but not at higher temperatures. Such effects may modify egg development rates as spawning progresses. In future, it should be possible to develop temperature-dependent egg development relationships conditioned on egg size. Egg size is more easily measured during AEPM compared with female traits, so applying these relationships would facilitate temporally resolved egg production estimates.

Reference:

C. J. Fox, A. J. Geffen, R. Blyth and R. D. M. Nash. 2003Temperature dependent development rates of plaice (Pleuronectes platessa L.) eggs from the Irish Sea. Journal of Plankton Research, 25(11): 1319-1329