area extending roughly from Pt. Baja to Pt. San 

 Juanico and extending some 200 miles offshore. 

 The peak of spawning in this area is in March- 

 April at temperatures of 13 .0° -16.5°C. This 

 area is continuous along a narrow coastal strip 

 with the area off southern California . 



3. Lower California inshore area: An 

 area extending roughly from the middle of 

 Sebastian Viscaino Bay to Cape San Lucas and 

 within 100 miles of shore. The peak of spawn- 

 ing in this area is in August September at 

 temperatures of 18" -23° C. 



4. Gulf of California: Very little is known 

 about the distribution of spawning within the 

 Gulf of California, or the temperatures at which 

 it occurs. However, collectio .s made in vari- 

 ous years and at different localities show that 

 sardines have spawned throughout the Gulf and 

 that the peak is probably in February -March. 



The extent of interchange between these 

 space time groups is not known and is, of course, 

 the critical question with which we are con- 

 cerned. It is known, however, that in 1952 and 

 1953 spawning off southern California was neg- 

 ligible; only about 4,000 billion eggs were 

 deposited in this area. But in 1954, some 

 114,000 billion eggs were spawned off southern 

 California by sardines which must (on the basis 

 of age-composition) have come from the south. 

 One might infer that these fish came from the 

 Lower California offshore area, since the fish 

 in these two localities spawn under approximate- 

 ly the same conditions and since the number 

 spawning in the southern area decreased in that 

 year. 



Tissue characteristics: (1) Immunologic- 

 al studies: In recent years there has been 

 increasing use of immunological techniques in 

 the study of blood characteristics with reference 

 to the distinctiveness and relationships of vari- 

 ous groups of animals. The most commonly 

 used techniques are the precipitin reaction and 

 the agglutination reaction (see Boyd, 1947, for 

 the description of these and other reactions) . 

 The desirable feature of such studies is that it 

 is possible to work with characters known to be 

 genotypic, whereas in morphological studies it 

 is generally difficult or impossible to ascertain 

 how much the genotype is molded or disguised 



by the phenotype . 



Gemeroy (1943), for example, has com- 

 pared the blood sera of 31 species of fresh and 

 salt water fishes. He found that the relationships 

 demonstrated in this manner in general follow 

 the conclusions based on morphological studies. 

 He concluded, however, that the gulf between 

 species and orders (as presently conceived) of 

 fishes is much greater than it is in birds . 



More recently Cushing(1952) ! ias investi- 

 gated the properties of blood sera of yellowfin 

 tuna (Neothunnus macropterus ) and oceanic skip- 

 jack ( Katsuwonus pelamis) from the central 

 Pacific . He found that at least four distinct blood 

 groups, on the basis of agglutinin content, were 

 present. He also pointed out the possible value 

 of such studies in distinguishing subpopulations 

 within species and the possibility that such dif- 

 ferences could serve as natural tags or markers . 

 He has informed me (letter dated February 20, 

 1953) that, because of the difficulty of securing 

 material among other things, his work will 

 probably not be expanded to include sardines. 

 However, the work has been extended to a number 

 of other species by Cushing and Sprague (1952, 

 1953) . 



Rechnitzer (1955) has studied the serolog- 

 ical properties (precipitin reaction) of members 

 of the family Enbiotocidae and has found that the 

 relationships thus shown are in agreement with 

 those inferred on the basis of morphology. 



(2) Chromotographic studies: The uses 

 to which column chromatography and, more re- 

 cently, paper partition chromatography have 

 been put are exceedingly diverse (see Stein and 

 Moore, 1951, Zechmeister and Cholnoky, 1941, 

 and Balston and Talbot, 1952 for descriptions 

 and examples of the methods) . A recent report 

 by Buzzati-Traverso and Rechnitzer (1953) in- 

 dicates that chromatograms of fish tissues 

 (muscle) show constancy within species and dis- 

 similarity between species . They also indicate 

 that this technique may be of use in distinguish- 

 ing subpopulations within a single species. 



Such studies of the sardine have been 

 pursued to some extent by Rechnitzer, but his 

 work is still in the exploratory stages. 



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