Aspects of the biology of the winter flounder, Pseudopleuronectes Americanus (Walbaum) in Long Pond, Conception Bay, Newfoundland.

Kennedy, Victor S. (1964) Aspects of the biology of the winter flounder, Pseudopleuronectes Americanus (Walbaum) in Long Pond, Conception Bay, Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

From November 1962 to October 1963, samples of winter flounder, Pseudopleuronectes americanus (Walbaum) were taken in Long Pond, Newfoundland. Found in shallow water (1-2 m.) from November until June, the flounder moved into deeper water (7-10 m.) during the summer and returned to shallow water in September and October. These movements out of and into shallow water corresponded with the end of the spawning season and the ripening of the gonads respectively. -- Flounder spawned from at least March until early June with the peak of activity in May and early June. Males ripened one or two weeks before females. The females were very fecund and there were great variations in fecundity for different individuals within the length, weight and age groups present. -- Most males were mature at age y and most females at age 7. 50% of the males and females were mature at 21 and 25 cm. respectively. The growth rates for males and females were similar until age 8 after which females outgrew the males. Growth was slower in Long Pond than in areas to the south. The length-weight relationships for males and females were similar. -- No feeding took place in December or January but flounder were feeding in March and continued throughout the summer with a decrease in food intake in the fall. They were omnivorous and the type of food eaten varied with the locality. Polychaetes and molluscs were important throughout the year. Capelin eggs and fish remains occurred only during a few months of the year but were eaten in great quantities. -- Polychaetes, winter flounder eggs and arthropods were not as important to the large fish as they were to the small. Capelin eggs and fish remains were eaten in quantity by the larger fish. The amount plant material ingested increased and debris decreased with increasing size. -- A trematode and a nematode were parasitic in the gut of winter flounder.

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