REPRODUCTIVE-BIOLOGY OF THE SMOOTH FLOUNDER IN GREAT BAY ESTUARY, NEW-HAMPSHIRE

The smooth flounder Pleuronectes putnami is the only small, boreal fla tfish species of inshore waters along the east coast of North America. Insights into the selection forces that shape the evolution of flatfi sh life histories can be gained by comparing the life history traits o f smooth flounder with those of the larger, deeper-dwelling flatfishes . We examined several aspects of the reproductive biology of a populat ion of smooth flounder in Great Bay estuary, New Hampshire. All males examined were sexually mature, including age-0 fish as small as 73 mm total length. Females matured during their first or second year at a m ean length of 97.7 mm. The small size and young age at maturity sugges t that the species is subject to high mortality, slow growth, or both. This would be consistent with their existence in highly variable bore al estuaries. Fecundity of 46 females 87-172 mm long ranged from 4,600 to 52,000 ova. The sex ratio overall did not differ significantly fro m 1:1. However, most of the largest fish were females and most of the smallest were males. There was no seasonal effect on sex ratios.