Infant survivalo - Having fully adjusted the data on numbers at each 

 stage of infant survival, its rate should be quite simply described by 

 a frequency distribution of the successive stages. The simplest result 

 to be expected would be a J=shaped ciirve transformable into a straight 

 line by suitable mathematical procedureo Differences from one season 

 to another in the slope of this line should register the changes in survival 

 rate. If, however, bhere are variations in that rate during the larval 

 existfSncej a more ccmples: curve would result and its interpretation would 

 be more difficulto 



Amount of spa-wningo -■ There are two approaches to the measurement 

 of amount of'~s"pimirng~through i) Computations from data produced by the 

 vital-statistics method that would effectively enumerate the spawning 

 stocks and 2) sampling the sea water for eggs. Both have serious obstacleso 

 The approach through spawning stock involves the appraisal of fecundity 

 of females by sizes or ages^ an appraisal rendered difficult for lack 

 of samples of spaTmers which resort largely to grounds farther offshore 

 than the area in which commercial fishing takes placeo4/ Therefore, 

 this approach has been indicated by a broken line in tTie diagram 'facing 

 page lo The approach through sampling for eggs is far simpler in principle, 

 and in terms of the diagram would be directly from the previous computa= 

 tion of total numbers. Howeverj, it involves surveying larger areas than 

 has so far been feasible with the single vessel available for this research. 

 Satisfactory enijmeration by either method depends on substantial augmenta- 

 tion of the sea work. 



Correlations with hydrographic and meteorological conditionso - So 

 far as recruitment'Ys~ determined by the amount of spawning and modified 

 only by the rate of larval survival, determination of the former and cor- 

 relation of the latter with hydrographic and meteorological conditions 

 would give the relationships necessary to the interpretation and predic- 

 tion of changes in recruitment rate. This correlation must relate to 

 the conditions in the one area of survey, but if it were found very exact 

 and involved hydrographic or meteorological features of wide-spread na- 

 ture, the results would possibly apply to the entire range of species. 

 It is more likely, however, that ttie more complex and extended procedure 

 discussed in the following paragraphs will be necessary. 



Multiple corr€<lation to distinguish effects of population density 

 from o ce anogra phi c ir f laences . - Thus far a rather simplified view has 

 been taken - one that stresses the laxn^al stages as the only factor crit- 

 ically modifying the relationship between amount of spawning and recruit- 

 mento A more comprehensive viewpoint would recognize that there are other 

 influences and that they may be exerted at any stage of life. To illustrate 

 this, the recrutiment diagram facing page 25 is given. Instead of a pro- 

 cedural diagram as in the one facing page 1, this is one of mathematical 

 equivalents and correlations. 



~^ Frances N. Clark, 1934, has studied fecundity in material taken from 

 the commercial catch. Her work proved the paucity of spawning-ripe 

 individuals in the catch and also the difficulties in determining the 

 numbers of eggs spavmed per female per season. 



24 



