Seasonal distribution, maturity, condition, and feeding of smooth flounder (Pleuronectes putnami) in the Miramichi estuary, southern Gulf of St. Lawrence

Abstract

Smooth flounder, Pleuronectes putnami, were collected by seine, trawl, and sampling of a commercial trap-net fishery in the Miramichi estuary in 1991–1993. Smooth flounder mainly occurred in the upstream half of the estuary during spring and summer but also occupied the lower estuary during late autumn and winter. Small (total length < 10 cm) fish were captured only in nearshore (< 1.5 m deep) waters during summer months but moved to deeper water during autumn. Large fish (> 15 cm long) were found only in the deeper (> 2.5 m) offshore waters. The size at which 50% of fish became sexually mature was 9.6 cm for males compared with 13.5 cm for females (presumed age 1 or older for both sexes). Most smooth flounder spawned during December. Body condition peaked during July, and lowest values were found during February; however, it probably declined further during March (when observations were not possible) because smooth flounder did not feed during winter months. Feeding activity was highest during June and July and declined during October and November, and all stomachs were empty during January and February. The principal prey of smooth flounder > 5 cm long was small bivalves. Very small amounts (never more than 5% of diet by mass) of sand shrimp (Crangon septemspinosa), crabs (Rhithropanopeus harrisi), and polychaetes were also eaten.