FISHERY BULLETIN: VOL. 81. NO. 1 



for 4 h (4-8 replicates). The carbon and nitrogen 

 contents were determined with a Hewlett- 

 Packard 2 Model 185B CHN Analyzer (3 repli- 

 cates) and the caloric content with a Parr 

 adiabatic bomb calorimeter (4 replicates). 



Five scales from each fish were mounted dry 

 between acetate sheets and examined under a 

 Wild M5 dissecting microscope at 18X. Annuli 

 were counted, and distances from the focus to 

 each annulus and to the scale margin were 

 measured with an optical micrometer on the 

 most symmetrical and clearly marked scale. 



Condition factor (CF) was calculated from the 

 following equation: 



CF 



wet weight (g) X 10 5 

 fork length (cm 3 ) 



(1) 



Length-weight relationships were determined 

 from functional regression of logio wet weight on 

 logio fork length (Ricker 1973. 1975b; Jolicoeur 

 1975). Functional regressions were used because 

 experimental error existed in both the x and y 

 values. Growth of the fish during 1976 was 

 determined by regressing the size of the fish (y) 

 against the date of capture (.r). Here, ordinary 

 regressions were used because error was 

 associated only with the y values. 



Table 1. — Size and condition of Atlantic menhaden caught in 

 Narragansett Bay, R.I.. during 1976, compared with those 

 caught in the North Atlantic during 1955-71. Means and 95% 

 confidence limits are shown for the Rhode Island data. Size of 

 menhaden during the years 1955-71 are taken from June and 

 Reintjes (1959, I960); June (1961); June and Nicholson (1964); 

 Nicholson and Higham (1964a, b. 1965a. b); Nicholson (1975). 



RESULTS AND DISCUSSION 



Atlantic Menhaden Age Structure, Size, 

 and Condition Factor 



Atlantic menhaden taken from Narragansett 

 Bay during 1976 were predominantly age 2 and 

 age 3 (Table 1), and the relative proportions of 

 the different age groups in the catch remained 

 approximately constant throughout the sam- 

 pling period. The high proportion (31.4%) of age 2 

 menhaden taken in the Narragansett Bay catch 

 during 1976 was unusual, based on records from 

 previous years. During 1955-71, age 2 menhaden 

 usually did not migrate in significant numbers 

 north of Long Island, although in some years 

 large numbers were observed in New England 

 waters (June and Reintjes 1959, 1960; June 1961; 

 June and Nicholson 1964; Nicholson and 

 Higham 1964a, b, 1965a, b; Nicholson 1975). 

 Also, the age distribution in the 1976 Narragan- 



2 Reference to trade names does not imply endorsement by 

 the National Marine Fisheries Service, NOAA. 



sett Bay catch (Table 1 ) was quite different from 

 that in 1975 (Ganz 1975), where, in a sample of 

 1,100, age 1 = 0.2%, age 2 = 14.6%, age 3 = 70.7%, 

 age 4 = 13.4%, and age 5 = 1.6%. 



Age 4 and older menhaden contributed signifi- 

 cantly in numbers and in biomass to the North 

 Atlantic catch prior to 1966 (Nicholson 1975). 

 However, during the mid-1960's these older age 

 groups dwindled until they became a negligible 

 part of the catch (Nicholson 1975). Small 

 numbers of age 4+ menhaden in Narragansett 

 Bay catches of 1975 (15.0%) and 1976 (7.7%) 

 indicate that the relative abundance of these age 

 "groups continues to be low. 



Menhaden caught in Narragansett Bay in 



1975 (mean weight 297.6 g (Ganz 1975)), and in 



1976 (this study), were considerably smaller 

 than fish of the same age caught during 1955-71 

 in the North Atlantic area (Long Island Sound to 

 Gulf of Maine) (Table 1). However, the condition 

 factor of the 1976 fish was similar to that of fish 

 previously caught in the North Atlantic (Table 

 1), implying that the basic length-weight 

 relationship was the same. 



134 



