A COMPARTMENTALIZED SIMULATION MODEL OF THE SOUTHERN NEW 

 ENGLAND YELLOWTAIL FLOUNDER, LIMANDA FERRUGINEA, FISHERY 



Michael P. Sissenwine 1 



ABSTRACT 



A compartmentalized simulation model of the Southern New England yellowtail flounder, Limanda 

 ferruginea, fishery was developed. The population was divided into 10 age-groups, each of which was 

 subdivided into 7 size categories. The model simulated discard mortality as well as natural mortality 

 and fishing mortality. Fishing and discard mortality rates depended on the level of fishing and on 

 gear and market selection factors. Both linear and density independent stock-recruitment functions 

 were considered. Seasonal variations in growth and exploitation were incorporated into the model. The 

 influence of fluctuation in temperature on recruitment and growth was also simulated. The model 

 using a linear stock-recruitment function accounted for 85.5% of the variability in the yield of the 

 fishery for 1943-65; with a density independent stock-recruitment function, the model explained 

 83.2% of the variability in yield for the same period. 



The linear stock-recruitment model was used to investigate the response of the fishery to alternative 

 fishing strategies. Substantial increases in the past yield of the fishery were indicated by the model 

 when fishing effort was concentrated during the second half of the year and when fishing effort 

 and discard mortality were reduced. 



This paper describes a compartmentalized sim- 

 ulation model of the Southern New England 

 yellowtail flounder, Limanda ferruginea (Storer), 

 population. There is evidence that production of 

 the Southern New England yellowtail flounder 

 population is influenced by environmental tem- 

 perature (Sissenwine 1974). The model is in- 

 tended to demonstrate the feasibility of predicting 

 catch under fluctuating environmental conditions 

 based on the rate of exploitation. The model 

 shares many of the characteristics of Walters' 

 (1969) "generalized computer simulation model," 

 which incorporates growth, fishing and natural 

 mortality, and a stock-recruitment relationship, 

 and also incorporates several additional features. 

 These features include 1) temperature dependent 

 growth and recruitment, 2) growth and fishing 

 mortality rates which vary seasonally, and 3) age- 

 groups subdivided into size categories. 



More than 600 thousand metric tons of yellow- 

 tail flounder valued at over $120 million have 

 been landed in Southern New England and 

 New York since the onset of fishing in the late 



Graduate School of Oceanography, University of Rhode 

 Island, Kingston, RI 02881; present address: Northeast Fish- 

 eries Center, National Marine Fisheries Service, NOAA, Woods 

 Hole, MA 02543. 



1930's. The magnitude of the fishery has stimu- 

 lated numerous quantitative investigations. 

 Royce et al. (1959), Lux (1964, 1969a), Brown and 

 Hennemuth, 2 Brown, 3 and Parrack 4 reported 

 catch and fishing effort data for each of the three 

 major fishing grounds (Lux 1963) since 1943. 

 Until recently, most of the catch has been from 

 the Southern New England ground. Catch and 

 fishing effort data were used by Sissenwine (1974) 

 to estimate the annual recruitment and equilib- 

 rium catch produced by the Southern New 

 England ground for 1944-65. The equilibrium 

 catch and recruitment were shown to be highly 

 correlated with the atmospheric temperature 

 record at Block Island, R.I. Lux and Nichy (1969) 

 determined the growth rate of the yellowtail 

 flounder. Lux (1969b) and Pitt (1971) calculated 

 the length-weight and length-fecundity func- 

 tions of the species, respectively. Mortality rates 

 of the yellowtail flounder were estimated by Lux 



Manuscript accepted January 1977. 

 FISHERY BULLETIN: VOL. 75, NO. 3, 1977. 



2 Brown, B. E., and R. C. Hennemuth. 1971. Assessment of 

 the yellowtail flounder fishery in Subarea 5. Int. Comm. North- 

 west Atl. Fish., Res. Doc. 71/14, Ser. No. 2599, 57 p. 



3 Brown, B. E. 1972. Current status of the yellowtail flounder 

 fishery in ICNAF Subarea 5 - January, 1972. Int. Comm. North- 

 west Atl. Fish., Res. Doc. 72/23, Ser. No. 2174, 18 p. 



4 Parrack, M. L. 1973. Current status of the yellowtail flounder 

 fishery in ICNAF Subarea 5. Int. Comm. Northwest Atl. Fish., 

 Res. Doc. 73/104, Ser. No. 3067, 3 p. 



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