FISHERY BULLETIN: VOL. 75, NO. 3 



TABLE 2.— Value of each parameter used to yield best results with yellowtail flounder model. The parentheses indicate values used for 

 the model in which recruitment is independent of spawning stock. L m i for i = 1,2,. . ., 7 are given in Table 3. 



Parameter 



Value 



Description 



Source 



From weight-length function (Equation (4)) 



From weight-length function (Equation (4)) 



First quarter seasonal effort factor 



Second quarter seasonal effort factor 



Third quarter seasonal effort factor 



Fourth quarter seasonal effort factor 



From fecundity-length function (Equation (14)) 



From fecundity-length function (Equation (14)) 



From proportion mature-length function (Equation (15)) 



From proportion mature-length function (Equation (15)) 



Proportion of females 



Slope of recruitment-temperature factor 



Slope of stock-recruitment function 



Slope of growth-temperature factor 

 Catchability coefficient 

 Minimum size retained by net 

 Size of maximum net retention 

 Minimum size at which fish are marketed 

 Size at which all fish are marketed 

 Mean temperature 

 Proportion entering size-class 1 

 Proportion entering size-class 2 

 Proportion entering size-class 3 

 Proportion entering size-class 4 

 Proportion entering size-class 5 

 Proportion entering size-class 6 

 Proportion entering size-class 7 

 Standard deviation of L m 

 Growth rate for fish less than 2 yr 

 Growth rate for fish greater than 2 yr 

 First quarter seasonal growth factor 

 Second quarter seasonal growth factor 

 Third quarter seasonal growth factor 

 Fourth quarter seasonal growth factor 

 Natural mortality of age-group 1 

 Natural mortality of age-group 2 

 Natural mortality of age-group 3 



Lux (1969b) 



Based on quarterly average effort data for 26 to 50 gross ton 

 vessel reported by Lux (1964) 



Pitt (1971) for fish from Grand Bank 



Based on percent mature data from Royce et al. (1959) 



Data on 9,268 fish provided by Northeast Fisheries Center 

 From recruitment estimates (Sissenwine 1974), see text 

 Fitted to catch data with the model, see text 



From annual growth estimates (Sissenwine 1975), see text 

 Sissenwine (1974) 



From length composition of catch for 1963, see text 



National Weather Service data, Block Island 



Arbitrary 



Data on 9,268 fish provided by Northeast Fisheries Center 

 \ See text 



I Based on length by quarter estimates (Lux and Nichy 1 969). see 

 text 



> See text 



The annual average air temperature at Block 

 Island was used as an index of temperature on the 

 Southern New England ground because there are 

 no water temperature records of adequate length 

 (1944 to present). Block Island is located on the 

 southwest edge of the Southern New England 

 ground. 



Taylor et al. (1957) concluded that air tempera- 

 ture data are a rough index of the general level 

 of surface water temperature. Colton (1968) 

 reported that trends in offshore water masses 

 paralleled trends in surface water temperature at 

 Boothbay Harbor, Maine. Lauzier (1965) used 

 trends in air temperature from 1875 to 1905 as an 

 index of the water temperature of the Gulf of 

 Maine. Templeman (1965) concluded that air 

 temperature at St. John's, Newfoundland, and 

 water temperature at Cape Spear for 1952-62 

 agreed extremely well. 



A record of the bottom water temperature at 

 Lurcher Lightship off Nova Scotia (Lauzier and 

 Hull 6 ) was collected from 1951 to 1969. The water 



depth was about 100 m. The correlation between 

 the average annual bottom water temperature at 

 Lurcher Lightship and the average annual air 

 temperature at Block Island is 0.78. The correla- 

 tion between the annual average air temperature 

 at Block Island and the annual average surface 

 water temperature at Woods Hole, Mass., for 

 data reported by Chase (1967) is 0.87 during the 

 period 1956-66. The correlation between monthly 

 averages of water temperature at Woods Hole and 

 air temperature at Block Island for this 132-mo 

 time series is 0.98. Therefore, Block Island air 

 temperature record was used as an index of water 

 temperature on the Southern New England 

 ground. 



The annual equilibrium catch of a fishery is the 

 level of catch that results in no change in the 

 biomass of the nominal stock (stock suitable for 



6 Lauzier, L. M., and J. H. Hull. 1969. Coastal station data 

 temperature along the Canadian Atlantic coast 1921-1969. 

 Fish. Res. Board Can., Tech. Rep. No. 150, 5 p. 



470 



