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FIRST DIRECTION «-BUTANOL ACETIC flCIO WATER - 2 1 HOURS 



Another reason is the possibility that 

 both leaching and partial decomposition of the 

 amino acids still remaining in the tissue may 

 have occurred in larvae which had been dead 

 prior to capture. That such incidence of mor- 

 tality among the larvae prior to capture is oc- 

 casionally quite extensive in restricted locali- 

 ties was shown by Strasburg (1959), who found 

 as nnuch as 99 percent mortality in the larvae 

 of frigate mackerel (Auxis sp. ) at one locality. 



There is also a remote possibility that 

 part of the inconsistency could have been the re- 

 sult of variations in the amino acid complex 

 caused by changes in the diet of the larvae. Evi- 

 dence of such variations in fish was found by 

 Farris (1958) in experiments with controlled 

 feeding of a sardine ( Sardinops caerulea ). 

 Whether dietary changes of such magnitude as 

 to cause variations in the annino acid complex 

 of tuna larvae do occur in nature, or the effect 

 this change has on the survival of the larvae is 

 not yet known. However, inasmuch as the possi- 

 bility does exist, such factors as this nnust be 

 considered. 



In view of the limitations in the experi- 

 nnental design and the failure in obtaining equal- 

 ly fresh adult samples of all the species tested. 



Figure 8. --Two-dimensional chromatogram of 

 adult bigeye run in reverse order of solvents. 



The only definite and consistent differ- 

 ence between adult and larval samples in both 

 one- and two-dimensional chromatogr ams was 

 the presence of a dark greenish-brown spot in 

 all the adult samples. This contrasted with the 

 purplish color exhibited by all other amino acids. 

 The spot, which was identified as aspartic acid 

 from chromatogr ams of 14 known amino acids 

 developed in identical solvents as the test sann- 

 ples, was notfound in any of the larval samples. 

 Inasmuch as adult samples of all the species 

 tested showed this particular amino acid, it is 

 believed that this acid reflects growth rather 

 than species difference. 



There are several hypothetical reasons 

 which may account for the inconsistency in the 

 results of the larval samples. One of these is 

 the probable reduction of amino acid concentra- 

 tion in the larvae owing to leaching. Larvae 

 used as sannples had been frozen and thawed re- 

 peatedly from the tinne they were first captured 

 to the time they were tested. Inasmuch as the 

 free amino acids found in animal tissues are 

 water soluble, it is reasonable to believe that 

 much of the amino acids had been lost during 

 the thawing processes. 



Figure 9. --Two-dimensional chromatogram of 

 adult yellowfin run in reverse order of solvents. 



