WINTER FLOUNDER PO P Ul.ATJ ON STUDIE S 



The winter flounder ( Pseudopleuronectes americanus ) is an important 

 sport and commercial finfish in Connecticut and is the most abundant 

 demersal fish in the Millstone area. Special emphasis has therefore 

 been placed on understanding the dynamics of the winter flounder stock 

 spawning in the nearby Niantic River. 



Results of studies conducted during 1983 were presented and, 

 whenever possible, compared to previous years. Included were the 

 population abundance survey in the Niantic river; age and growth, 

 survival, reproduction, and movements of adults; early life history 

 studies; impingement and entrainment at MNPS; and models of 

 fluctuations in the catch of winter flounder. 



An estimated 41,980 ± 15,564 winter flounder larger than 20 cm were 

 in the Niantic River during the spawning period. The mark and recapture 

 data were examined for potential sources of bias or error; the abundance 

 estimate was relatively unbiased and precision was good. Estimated 

 abundance declined 28% from 1982 and 15% from 1981, but remained larger 

 than during the late 1970's. The number of small winter flounder ( < 20 

 cm) decreased more than a third from 1982 but this difference may have 

 been partly related to changes in survey design. 



The median was chosen as the most representative catch statistic 

 for trawl CPUE during the surveys. Standardization of trawl distance 

 and number of tows allocated by station reduced the variability of the 

 1983 data compared to previous years. The annual median CPUE and 

 abundance estimates followed somewhat different trends. The largest 

 difference occurred in 1982, which had an abundance estimate similar to 

 1981 but a significantly smaller median catch. 



Spawning of winter flounder began in January or early February 

 under the ice in the upper river; little spawning apparently took place 

 outside of the river. Adult sex ratios have been 1.21 to 2.03 in favor 

 of females since 1977. The median size of mature females was estimated 

 as 25.1 cm. Annual estimates of reproduction showed that female 

 spawners and egg production peaked in 1982 with the 1983 and 1981 

 estimates comparable in magnitude. 



