Her conclusions (1947:5-6) are: 



These vertebral counts indicate that 

 sardines from British Columbia to Pt . San 

 Eugenio in central Lower California comprise 

 a mixture of populations, the young of which 

 may have been reared on nursery grounds in 

 any of these localities. For most seasons, 

 presumably, the nursery grounds off California 

 and northern Lower California make the great- 

 est contributions to the population. 



"Sardines living off southern Lower 

 California and in the Gulf of California probably 

 comprise a distinct group which does not mix 

 with the northern fish; or if a mixture occurs, 

 the proportion of southern fish to the total 

 northern population is small. 



' The interchange between nursery grounds 

 begins early, perhaps before the sardines are 

 a year old. 



"The number of vertebrae varies between 

 year-classes, and certain year-classes are 

 characterized by high or low averages in all 

 localities . 



"The average number of vertebrae is ap- 

 proximately 51.7 for all sardines north of south- 

 ern Lower California." 



Although it was not specifically stated, 

 Clark's use of the word "population" indicates 

 an association of fish which have some distinct 

 character, specifically, some unique average 

 number of vertebrae . (This is what I have 

 called a group.) 



McHugh (1950) has presented additional 

 data on vertebral numbers in sardines . Using 

 collections of "postlarval" sardines from north- 

 ern California, southern California, northern 

 Lower California and southern Lower California, 

 he demonstrated the latitudinal differences pre- 

 viously noted by others . He also found seasonal 

 differences within a single geographical area 

 which exceeded in magnitude the differences 

 observed between areas. 



(2) Other meristic characters: Although 

 meristic studies of sardines have been based 



largely on vertebral counts, some use has been 

 made of other characters. Taranets (1937) 

 compared the number of transverse rows of 

 scales and the number of gill rakers in sardines 

 from the eastern and western North Pacific. He 

 did not consider differences within the local 

 population . 



The California Marine Research Com- 

 mittee (1950:42) briefly mentions: Studies of 

 other characters, such as the numbers of fin- 

 rays and of gill-raKers, now under way, so far 

 suggest that intermingling is not complete be- 

 tween Southern /Bic/ California and the regions 

 to the north." Presumably, this refers to work 

 now being carried out by Wisner. As mentioned 

 above, it now appears lively that this work will 

 not be pertinent to studies at the subpopulation 

 level. 



McHugh (1950:67) has examined "unpub- 

 lished data on dorsal and anal fin -ray counts of 

 adult and young /sardines/made by H.C. Godsil 

 and W.E. Barraclough ."37 According to McHugh's 

 analysis of these data, the anal fin ray numbers 

 show the presence of more than one group in the 

 area from British Columbia to southern California 

 and more than one group in the area south of 

 southern California . The mean number of anal 

 fin rays increased from British Columbia to 

 southern California and decreased south of 

 southern California. 



The data on numbers of dorsal fin rays 

 showed no consistent variation and McHugh sug- 

 gests that counting errors may be responsible for 

 this. 



With regard to morphometric, meristic 

 and perhaps other characteristics, it is pertinent 

 to reiterate that these may be considerably modi- 

 fied by environmental conditions, especially 

 during the early stages. This has been demon- 

 strated experimentally for some species (Gabriel, 

 1944. Timing, 1944, 1946, 1952; Martin, 1949; 

 Bailey and Gosline, 1955) and inferred on the 

 basis of observations in nature for many other 

 3/ According to McHugh. Godsil reported on his 

 findings in a manuscript which was not published 

 owing to Godsil' s uncertainty as to the accuracy 

 of the fin-ray counts (which are difficult to make) . 

 I have not seen Godsil's manuscript. 



Ill 



