Several special studies and analyses were conducted to identify possible sampling biases in the larval 

 winter flounder data base. The results of these studies included reduced larval net extrusion with 202-fim 

 mesh nets compared to 333- and 505-jim nets, increased sample density of larger larvae in night 

 collections, and changes in sample densities in relation to tidal stage at a station in the lower portion 

 of the Niantic River. Due to the identified sample biases, much of the offshore data collected prior to 

 1980 could not be used to examine the life history of larval winter flounder. 



Based on the abundance and distribution of smaller larvae, spawning primarily occurred in the 

 Niantic River. larvae were gradually flushed into Niantic Bay, where larger larvae dominated. The 

 spatial distribution of larvae within the Niantic River varied from year to year, but generally smaller 

 larvae were more prevalent in the upper portion of the river and larger larvae in the lower. The lion's 

 mane jellyfish was identified as an important predator of larval winter flounder. 



Eight tidal export-import studies were conducted at the mouth of the Niantic River during 1983-85. 

 The results showed a net export of 4 mm and smaller winter flounder larvae and a net import of 5 mm 

 and larger larvae. Larvae with developed fin rays migrated vertically in response to tidal currents to 

 reenter the Niantic River and those within the river demonstrated a similar behavior as a retention 

 mechanism. 



Examination of otoliths from field-collected and laboratory-reared winter flounder larvae indicated 

 that daily increments were not visible. Based on the length-frequency distribution, most larval mortality 

 occurred at the time of first feeding (3-4 mm). Transition to the demersal juvenile stage occurred at 

 about 6-7 mm. 



Abundance of post-larval young-of-the-year peaked in mid-June and stabilized by late July. Young 

 were most numerous in the lower river during 1983, with similar densities found during 1984 and 1985. 

 Growth of young in the lower river was significantly greater than at stations farther upriver after 

 mid-June. Weekly mean lengths in 1983 were about 6 to 8 mm larger than in 1984 or 1985. Monthly 

 survival estimates of young ranged from 0.552 to 0.569 in the lower river and 0.661 at a station in mid-river. 



Peak abundance of age 1 juvenile winter flounder taken in the Niantic River during the adult 

 surveys occurred in 1981, with second and third highest CPUE in following years. An 11 -yr low was 



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