6G FISH AND fiAME COMMISSION. 



Ill lieu (if fliU'tuatiniis ill catcli due to llic iircsciicc ol" (luiiiiiiant or 

 siii)pressed apre cjroups, tliciv have Iwvw i'oiuid great c-liaiifres due to 

 the sensitiveness of the alhaeore 1o pliysical eonditions. At the present 

 stage of tlie woric, this analysis has been "arricd only so far as to com- 

 pare the different sections of the individual I'uns. It will, however, now 

 be attempted to carry the analysis to a comparison of the annual 

 chaii<ri's with whatever oceanographical or cliinatological data are 

 available. It is entirely ])ossil)le that the albacore runs as a whole vary 

 with, and tliat their magnitudes are the result of, conditions existing 

 previous to the runs themselves. In such case the prophesying of the 

 commercial catch may be possible. Such a case has been supposed to 

 exist in regard to the mackerel off the British coasts, but the data upon 

 which the reasoning was based seem to us very unsatisfactory and as 

 they have never been followed up. we can place no dependence upon 

 the relationship supposed to exist. It would appear that our knowledge 

 of the albacore runs is so thorough that we can logically hope for far 

 more satisfactory results than in that case, and it is the present inten- 

 tion to follow the work through. 



It is the hope of the laboratory staff that it may at some time in 

 the future be able to utilize a boat in follo\ving up this clue to the 

 behavior of the albacore. This boat should make a daily traverse of 

 a given region, taking careful scientific records, until a run occurred. 

 Thereby it would be possible to definitely assign the runs of fish to the 

 correct causes. As w^e have plotted the localities in which runs 

 occur, it seems to us entirely feasible to accomplish this. 



It may be pointed out that, as in the case of the sardine, there has 

 been attained at least partially the first step in the understanding of the 

 catch. The varying characteristics of the catch have been accurately 

 recorded, and the actual variation brought to light as far as possible, 

 both as regards the varying classes of fish taken, and as to the varying 

 size of the catches. This, the first step in any scientific analysis of a 

 natural phenomenon, is a secure basis upon which to base decisions. 



However, in considering the detection of overfishing we have found 

 that the presence of this great variability in catch ha.s the same effect — 

 in lesser degree perhaps — that it did upon the detection of overfishing 

 in the case of the sardine, that is, to render it more difficult. A per- 

 sistent decrease in proportion of mature fish and in average catch 

 per boat must be brought to light, and must exceed so clearly the inci- 

 dental variations as to be unmistakably significant. Not merely must 

 there be known the proportion of each age in the samples obtained by 

 this rigid system, but there must be carried forw'ard a comparison of 

 the average boat catch each year during the runs of the smaller or 

 larger fish. The need for tlip "pink ticket" system is obvious and 

 great. It can not be dispensed with lest we lose the most of our signifi- 

 cant evidence. 



The bearing upon theories of migration of the observed correlation 

 between the albacore runs and the changes in climatological factors, 

 deserves to be sharply emphasized. It has been possible to demonstrate 

 this correlation to a sufficient extent so that it seems fairly certain that 

 the minor intraseasonal so-called "runs" are not due to incoming 

 schools but to schools which are already present. None of the evidence 

 of migration has been found to bear critical examination. We must 



