Length-Weight Relation of the Summer Flounder 

 Paralichthvs dentatus (Linnaeus) 



By 



FRED E. LUX and L. R. PORTER, Jr.^ Fishery Biologists (Research) 



Bureau of Commercial Fisheries Biological Laboratory 

 Woods Hole, Mass, 



ABSTRACT 



Length- weight equations of the form W = c L*" in which W is weight, L is length, 

 and c and b are constants are given for summer flounder for each calendar quarter. 

 Weight for a given length varied seasonally. Males were slightly heavier than females 

 of the san-ie length. 



INTRODUCTION 



Infornnation on the length- weight relation of 

 fish is needed in studies of condition, growth, 

 and sexual maturity, and in investigations of 

 exploited species to obtain weight yields by size 

 and age groups from length- and age-frequency 

 samples of the catch. The summer flounder, 

 or fluke, is important to otter-trawl fishermen 

 and anglers in New England and Middle At- 

 lantic States (Bigelow and Schroeder, 1953). 

 The only previously published information on 

 its length- weight relation was based on meas- 

 urements of 118 fish from Chesapeake Bay 

 (Hildebrand and Schroeder, 1928). The present 

 report gives estimated length- weight relations 

 by calendar quarter for fish from catches by 

 New England otter trawlers. 



Summer flounder are most abundant in the 

 Middle Atlantic Bight, the area between Cape 

 Cod and Cape Hatteras, and are found close 

 inshore in bays and sounds during late spring 

 to fall and on offshore grounds between the 40- 

 and 85-fm. (fathom) contours in the winter and 

 early spring. Tagging studies have shown that 

 a seasonal inshore-offshore migration occurs 

 and that fish from inshore and offshore grounds 

 are of the same general population (Poole, 

 1962). 



Summer flounder spawn during the fall 

 migration from inshore to offshore grounds. 

 At that time, they are not concentrated and 

 few New England vessels fish for them; as 

 a result no gravid fish were available for 

 inclusion in this study. 



The New England catch is from the northern 

 part of the Bight (fig. 1), inshore from Block 

 Island to Nantucket Sound in the summer and 

 offshore from Huds/sn Canyon to Veatch Canyon 



in the winter. The fish for this study were 

 caught on these grounds. 



METHODS 



Length- weight equations were computed 

 from lengths and weights of 2,051 fish caught 

 in 1956-62. Of these, 1,705 were obtained 

 from commercial landings and 346 were from 

 the catch of a research vessel. Most months 

 were represented (table 1), 



Table 1. — Number of summer flounder obtained 

 from commercial landings, by month 



Includes the sample of 3^6 fish caught by 

 a research vessel. 



Commercial landings were sampled at New 

 Bedford, Mass., and Point Judith, R, I, Summer 

 flounder in these ports are sorted into four 

 size categories and packed in boxes of 125 lb, 

 (pounds) upon their removal from the fishing 

 vessels. Boxes of fish were selected arbi- 

 trarily, and all fish from a box were measured 

 and weighed so that no selection by size or 

 sex was made within a box. The larger fish 

 were sampled out of proportion to their 



L. R. Porter, Jr. is now with Bureau of Sport Fisheries and Wildlife, Branchof River Basin Studies, Sacramento, Calif. 



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