REGIONAL VARIATIONS IN THE GROWTH AND AGE COMPOSITION 

 OF NORTHERN ANCHOVY, ENGRAULIS MORDAX 



R. H. Parrish,! D. L. Mallicoate,! and K. F. Mais^ 



ABSTRACT 



Data from the Sea Survey Program conducted by the California Department of Fish and Game were 

 analyzed to describe regional variations in growth and age composition of northern anchovy, Engraulis 

 mordax. Juvenile growth appeared to be greater at higher latitudes and in the offshore portion of the 

 Southern California Bight. Adult growth was less variable; however, there were statistically significant 

 differences between regions. In addition, the growth rate for the southern stock was markedly lower than 

 that of the central stock. This difference in growth rates was used to characterize the area of overlap 

 between the two stocks. Age composition varied with depth of water and geographical location within 

 the Southern California Bight and with latitude Young-of-the-year and yearling fish were found in larger 

 proportions in shallow water and in the southern and inshore areas of the Southern California Bight. 

 Age compositions of northern anchovies sampled in the California and Mexican purse seine fisheries were 

 compared with those of the Sea Survey Program. This comparison suggests that the present California 

 area restrictions, which exclude the fishery from the nearshore area, greatly reduces the number of young 

 fish in the catch. 



The purpose of this study is to describe regional 

 variations in growth and age composition of the 

 northern anchovy, Engraulis mordax. Data for the 

 study were taken by the Sea Survey Program of the 

 Cahfornia Department of Fish and Gama Mais 

 (1974) described this program and analyzed the data 

 for the most common species taken in the survey. 

 This report is an extension of Mais' work and focuses 

 on geographical variations in age composition and 

 growth rates and on depth variations in age 

 composition. 



Meristic and morphometric (McHugh 1951) and 

 electrophoretic (Vrooman et al. 1981) studies on the 

 stock structure of the northern anchovy suggest that 

 there are three stocks (northern, central, and 

 southern) and that the boundaries between the 

 stocks occur in central California and central Baja 

 California. There is also recent evidence (Parrish^) 

 of a fourth stock which spawns in the fall in central 

 California and in the northern and offshore areas 

 of the Southern California Bight. 



Mais (1974) showed that the southern stock of 

 northern anchovies was smaller at age than the cen- 

 tral stock. In addition, northern anchovies are known 



'Southwest Fisheries 'Center Pacific Fisheries Environmental 

 Group, National Marine Fisheries Service, NOAA, P.O. Box 831, 

 Monterey, CA 93942. 



^California Department of Fish and Game, 1301 West 12th Street, 

 Long Beach. CA 90813. 



^Parrish, R. H. 1983 Evidence for a fall spawning anchovy 

 stock. Paper presented at 1983 CalCOFI Conference 



Manuscript accepted January 1985. 

 FISHERY BULLETIN: VOL. 83, NO. 4, 1985. 



to be larger off central California than off southern 

 California (Collins 1969; Mais 1974; Mallicoate and 

 Parrish 1981), and they are larger in the offshore 

 areas of the Southern California Bight than in the 

 inshore areas (Mais 1974). These differences could 

 be due to varying growth rates between regions, 

 varying seasonality of spawning, varying age com- 

 positions, size-specific migration, or a combination 

 of these factors. 



Tkgging experiments have shown that northern an- 

 chovies move from southern California to central 

 California, from central California to southern 

 California, and from southern California to 

 Ensenada, Mexico; there is a northerly movement 

 in summer and a southerly movement in winter 

 (Haugen et al. 1969). Mais (1974) found northern an- 

 chovies to be distributed more offshore in some years 

 and more inshore in other years, and he found them 

 concentrated closer to shore and in the northern part 

 of the Southern California Bight during the fall 

 months. Mais (1974) suggested that northern an- 

 chovies begin an offshore and southeastward move- 

 ment in late winter, which coincides with the onset 

 of major spawning activity. These movements of 

 anchovy may affect the measurement of growth 

 rates and age compositions within the different 

 regions. 



METHODS 



The data used in the study were taken from north- 



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