AGE AND GROWTH OF THE WINTER FLOUNDER, 

 PSEUDOPLEURONECIES AMERICANUS, ON 



GEORGES BANK 



Fred E. Lux^ 



ABSTRACT 



Lengths calculated at each scale annulus from 5 10 winter flounder, Pseudopleuronectes 

 ainericanus, collected on Georges Bank during 1963-66 provided a measure of growth up to 

 12 years of age. Growth was more rapid on Georges Bank than on inshore areas. Females 

 grew faster than males after age 2. Fish from eastern Georges Bank grew slightly faster 

 than those from western Georges Bank. Bertalanffy growth equations were computed for 

 each sex. 



The winter flounder, Pseudopleuronectes ameri- 

 cauus (Walbaum), found in Atlantic coastal 

 waters from Newfoundland to Cape Hatteras, is 

 a common fish in the New England and middle 

 Atlantic catch. Landings by commercial fisher- 

 men, mostly with otter trawls, averaged 12,000 

 metric tons annually in the period 1966-70. In 

 addition, there is a large sport fishery since 

 the species occurs in shallow coastal waters 

 easily accessible to saltwater anglers. The 

 estimated angler catch in 1965 was 13,000 tons 

 (Deuel and Clark, 1968). 



Most of the catch is made in the New England 

 area where the species is found on both inshore 

 and offshore grounds. There appear to be a 

 number of distinct groups in this area, judging 

 from movement of tagged fish and variation in 

 numbers of fin rays (Perlmutter, 1947; Bigelow 

 and Schroeder, 1953; Lux, Peterson, and Hut- 

 ton, 1970). One of these groups is on Georges 

 Bank where the fish are larger and have more 

 fin rays than on inshore areas. There is almost 

 no movement of winter flounder between Georges 

 Bank and inshore grounds. The growth material 

 presented here is for winter flounder from 

 Georges Bank. 



On the basis of size, color, and fin ray number, 



' Northeast Fisheries Center, National Marine Fisher- 

 ies Service. NOAA, Woods Hole, MA 02543. 



Manuscript accepted October 1972. 



FISHERY BULLETIN: VOL. 71, NO. 2, 1973. 



Kendall (1912) determined that the winter 

 flounder from Georges Bank comprised a 

 separate species, which he named P. digiiabilis. 

 Bigelow and Schroeder (1953), however, con- 

 sidered the differences as no more than racial, 

 a view which presently prevails. 



Studies of winter flounder growth on inshore 

 areas, summarized by Berry, Saila, and Horton 

 (1965), Poole (1966), and Kennedy and Steele 

 (1971) indicated that age determination from 

 hard body parts is difficult and that growth 

 rate varied with area. Females grew faster 

 than males, at least after the first few years. 



There is no previous study on grovii;h of 

 winter flounder on Georges Bank although it 

 has long been known that winter flounder there 

 grow much larger than on inshore grounds 

 (Bigelow and Schroeder, 1953). 



MATERIALS AND METHODS 



The fish for the study were obtained from 

 research vessel and commercial catches in 

 1963-66. The research vessel samples were 

 from National Marine Fisheries Service Al- 

 batJ'oss /Fgroundfish surveys (Grosslein, 1969). 

 Since the otter trawl used had a V2-inch mesh 

 liner in the cod end, both large and small fish 

 were obtained. Six additional samples were 

 collected from catches of commercial otter 

 trawlers, and these contained only fish greater 

 than 36 cm in total length. 



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