MacGREGOR: ADDITIONAL DATA ON SPAWNING OF HAKE 



33 to 766 and averaged 248. This compares with 

 38 to 556 with an average of 216 for the ad- 

 vanced eggs for all samples. 



The correlation obtained by MacGregor 

 (1966) between percentage of eggs in the ad- 

 vanced mode and advanced eggs per gram of 

 fish has no mathematical significance because 

 both variables are related. Actually there is 

 no relation between the number of advanced eggs 

 and the number of small eggs. Ovaries con- 

 taining either high or low numbers of advanced 

 eggs per gram of fish may contain either high 

 or low numbers of small-yolked eggs. How- 

 ever, the conclusion that the great variation in 

 the ratios of large to small eggs makes multiple 

 spawning unlikely seems to be valid. 



Of 366,093 hake larvae taken on monthly 

 cruises in the 6 years 1951 through 1956, 87% 

 were taken in January, February, and March, 

 11.5% in April, and the remaining 1.5% in the 

 remaining 8 months. Several large samples of 

 hake taken off California in April 1970 showed 

 that the advanced eggs were no longer present 

 in the ovaries of the females while the smaller 

 yolked eggs were. Because there is no evidence 

 of further egg development in the ovaries and 

 no evidence of heavy spawning subsequent to 

 April in the plankton, we must assume that these 

 small-yolked eggs are resorbed following spawn- 

 ing of the advanced mode. 



SIZE AT FIRST MATURITY 



One hundred thirty-six hake from sample 

 J-45-13 (southern Baja California) were ex- 

 amined for stage of sexual maturity. Eighty 

 hake from sample J-45-27 (central Baja Cali- 

 fornia) and an additional seven hake taken in 

 1961 near Cedros Island (central Baja Cali- 

 fornia) were also examined (Table 3). 



In sample J-45-13 the largest immature male 

 was 127 mm in length, and the largest immature 

 female 138 mm. The smallest maturing male 

 was 119 mm. and the smallest maturing female 

 125 mm. All males 129 mm and longer and all 

 females 140 mm and longer were maturing. 



In sample J-45-27 the range of fish length was 

 not as good for determining size at first maturity. 

 The smallest maturing male was 137 mm long, 

 and it appeared that all males 159 mm and long- 

 er were matui-e. The smallest mature female 

 was 222 mm in length, and all females of this 

 length and longer were maturing. However, 

 on the basis of the 1961 sample it appears that 

 all females were maturing at some length be- 

 tween 202 and 222 mm. 



It is difficult to determine the size at first ma- 

 turity for hake off northern Baja California and 

 California because very few fish of suitable size, 

 taken during the spawning season, were avail- 

 able. For off-season hake the gonad index may 



Table 3.— Size at first maturity. Southern Baja California, sample J-45-13, lat 27°07' N, long 113°07' W, January 

 11, 1970. Central Baja California (Cedros Island area), sample J-45-27, lat 28°44' N, long 115°15' W, January 16, 

 1970, and sample B-6111-3, Cedros Island, November 25, 1961. Males judged mature or immature by size and appear- 

 ance of testes. Females judged immature if largest eggs in ovary were 0.20 mm or less in diameter (not yolked) ; 

 probably maturing if ma.ximum egg diameter was 0.23 to 0.47 mm; mature if maximum egg diameter was 0.50 mm 

 or larger. Immature, not sexed: gonads not developed enough so that se.\ can be determined by gross examination. 



J-45-13 



137-140 

 159-307 



Maximum egg diameter (mm) 



0-0.20 



0.37 



0.67-0.83 



42 



583 



