METHOT: SURVIVAL OF LARVAL ENGRAULIS MORDAX 



Table 4. — Size distributions of juvenile northern anchovy calculated from 

 size distributions of all fish and size-specific juvenile fraction (Table 1). The 

 percentage of the population composed of juveniles was also calculated (7c 

 juveniles). Area is the surface area (square nautical miles) nearshore of the 

 50 fathom isobath and excludes the shallow area around islands that was 

 not sampled. 



-30 30 60 90 120 150 180 



DEC JAN FEB MAR APR MAY JUN 



- 1977 -»t- 1978 > 



- 1.500 >f 



1.000 Z 



FIGURE 2. — Comparison of the seasonal distributions of northern 

 anchovy larval abundance and birth dates of the 1978 year class. 

 The width of the stippled bars is the effective duration of the 

 ichthyoplankton survey (±2 standard deviations of the sample date 

 where each sample is weighted by its catch of northern anchovy lar- 

 vae). The dashed line was used to interpolate larval abundance per 

 30-d period. The open histogram indicates the fraction of juvenile's 

 birth dates occurring per 30 d. 



TABLE 5. — Frequency of observed birth dates of juvenile 

 northern anchovy stratified by year and region and sum- 

 marized by 10-d date interval. 



-30 30 60 90 120 150 180 

 DEC JAN FEB MAR APR MAY JUN 



-1978-H-1979- 



FlGL'RE 3. — Comparison of the seasonal distributions of northern 

 anchovy larval abundance and birth dates of the 1979 year class. See 

 Figure 2 for explanatioa 



December- January for northern fish. The calculated 

 birth-date distributions were similar to the observed 

 birth-date occurrences in the two regions in 1 978; the 

 calculated differed from the observed in 1979 

 because selection of specimens was highly nonran- 

 dom in 1979. A substantial fraction of 90-110 mm 

 fish in 1979 were assigned to birth dates before 

 December 1978. Because these fish had no otolith 

 annulus they are considered part of the 1979 year 

 class. 3 



'Among the 95-105 mm anchovy examined in 1979, all those with 

 an annulus (1978 year class) had 400-510 daily increments so had 

 been born during summer of 1978. Among the similar-sized fish 

 without an otolith annulus, some had been born in December 1978 

 and some as early as late summer 1978. This observation indicates 

 the occasional ambiguity of assigning year classes when some spawn- 

 ing occurs throughout the year. 



745 



