FISHERY BULLETIN: VOL. 69, NO. 3 



indicate maturity. Generally, hake with gonad 

 indices of less than 0.5 (i.e., the gonad weight 

 is less than 0.5^/r of the fish weight) do not con- 

 tain yolked eggs in their ovaries. There is no 

 yolk in eggs up to 0.20 mm diameter, and fish 

 containing such eggs a few months before or 

 after the spawning season may be considered 

 immature. Eggs in an ovary having a gonad 

 index of 0.8 have a maximum diameter of about 

 0.34 mm and at a gonad index of 1.5, about 0.43 

 mm maximum diameter. The eggs generally are 

 not large enough to count (over 0.65 mm diam- 

 eter for the largest eggs in the ovary) until 

 the gonad index is about 3.5, and then only for 

 fish having a fecundity of less than 100 eggs 

 per gram of fish. If we apply the same criterion 

 (a gonad index of less than 0.5 as indicating an 

 immature fish) to the males, we can roughly 

 estimate the size at maturity for off-season hake. 



Applying this criterion of maturity to a num- 

 ber of miscellaneous hake samples taken in the 

 off-season for spawning off northern Baja Cal- 

 ifornia and southern California, it appears that 

 all males 285 mm and longer and all females 

 340 mm and longer were mature. 



Best (1963) estimated that all hake, both 

 males and females, taken off northern California 

 were mature at 400 mm total length (about 360 

 mm standard length) . The length at which all 

 fish are mature could be somewhat less as he 

 had a limited number of smaller fish in his 

 samples. 



Nelson and Larkins (1970) found that all fish 

 of 450 mm total length (about 405 mm standard 

 length) were mature in the Pacific Northwest. 

 Apparently they also had few smaller fish to 

 work with, and the length at which all fish are 

 mature could be somewhat less. 



DISCUSSION 



The mean number of eggs per gram of fish 

 was not significantly different among the three 

 samples, ,1-45-13, J-4.5-27, and Cobb 1963. These 

 three samples were taken in widely separated lo- 

 calities, and although they were similar with 

 respect to relative fecundity, questions have been 

 raised as to the distinctness of the north Pacific 

 hake with respect to race or even species. 



Ginsberg (1954) assigned the north Pacific 

 hake to two species based on morphometric and 

 meristic characters. His descriptions were 

 based on 12 specimens of Merlucchis productus 

 taken off Washington, Oregon, and California, 

 as far south as San Diego, and eight specimens 

 of M. angustimamis taken in the Gulf of Panama, 

 the Gulf of California, off the Pacific Coast of 

 Baja California, and off Del Mar, Calif. 



Ahlstrom and Counts (1955) could find no evi- 

 dence of more than one species of hake in their 

 extensive collections of eggs and larvae taken 

 Ijetween San Francisco and the southern tip of 

 Baja California. All of the small fish that had 

 fully developed dorsal and anal fins had fin ray 

 counts that fell within the range of M. productus 

 but outside of the range of M. angustimanus as 

 given by Ginsberg. 



F. H. Berry (unpublished data) studied nu- 

 merous additional specimens of hake from Baja 

 California and California. He concluded that 

 M. jyvoductus and M. angusthnanus were the 

 same species and the differences in meristic and 

 morphometric characters, used by Ginsberg to 

 separate the species represented a latitudinal 

 cline. 



There was certainly a marked cline in size at 

 maturity for the hake used in this study, espe- 

 cially when these data are compared with data 

 given by other authors. The size at which all 

 fish were mature was as follows: 



Southern Baja Californi,! 



Ccmral Baja Californi; 



Sex Standard 



Imgth 



males 129 mm 



females 140 mm 



males 1S9 mm 



females 202-233 mm 



NortKeni Baja California and southern California males 385 mm 



females 340 mm 



Norlhcrn California (Best. 1%3) 



Pacific Northwest (Nelson and Larkins. 1970) 



both 

 both 



360 mm 

 40? mm 



The difl^'erences between areas are so great that 

 the roughness of some of the estimates does not 

 affect the conclusion that these differences are 

 very real. 



The distribution and growth jiatterns of the 

 European hake, M. merlucciiis, is similar to that 

 of M. prndKcfus in many ways. The Euroiiean 

 hake ranges from Norway to at least Mauritania 

 ill Africa (Hart, 1948) while .1/. productiis 



584 



