transformed paired catches, and then interpreting the "discrepance" 

 as an estimate of the variance of a single subset. The only deviation 

 from the usual computational technique was the rejection of sets of 

 paired data of which one member was a zero. This was done because 

 the effect of this alteration was less serious than the effects of the 

 more comnnonly used adjustments for zero values. It resulted in re- 

 jection of as much as one-sixth of the data from one set, probably 

 reduced the variance slightly, and of course limits the analysis to 

 catch rates of more than one fish per 100 hooks. 



The first series of fishing stations subjected to analysis of 

 variance furnished estimates for 18-, 37-, and 74-basket sets of 

 longline gear. The actual amount of gear fished during these stations 

 varied fronn 60 to 84 baskets, 80 being the most typical number. 

 Replicate fishing stations were obtained as follows s First, each 

 station's set was divided into four subsets by combining the catches 

 of every fourth basket, yielding 104 subsamples from 26 stations^ 

 (Equal numbers of baskets were obtained in each subset by discard- 

 ing the last one, two or three baskets of a station when necessary)o 

 The 104 subsamples were formed into a series of 52 paired subsamples 

 by pairing those derived from adjacent baskets, and two pairs were re- 

 jected because they contained a zero value. The mean number of baskets 

 in this series was 18. Next, each of the 26 stations was divided into 

 paired subsamples by pooling the catches of alternate baskets, again 

 discarding superfluous baskets at the end of the set of gear. The mean 

 number of baskets in this series was 37, Finally, each station was 

 regarded as a unit, and stations occurring on consecutive days were 

 paired yielding 14 pairs with a nnean of 74 baskets. 7/ 



Analyses of variance 8/ of these sets of catch records (table 3) 

 indicate a substantial reduction in the estimated a- with increasing 



7/ During the collection of these data the geographical distance between 

 any two consecutive stations was slight, and certainly did not involve 

 movement to another zone of the ocean. There is, then, a priori 

 reason to regard the catch on a succeeding day as a replicate. Two 

 additional stations were used in this series which could not be used 

 previously because only the total catch was recorded. 



8/ In the connputation the logarithms of the catches shown in table 8 

 ~ (see appendix) were utilized. Since unequal amounts of effort are in- 

 volved in some pairs in the 74-basket series, a simple ratio adjust- 

 ment was applied to all members so as to equate the catches to 

 those to be expected had there been 80 baskets in each pair. The use 

 of the less tedious 80 basket adjustment is mathematically justified 

 because of the use of the logarithms of the variates. 



13 



