for each of the eight distributions equals or nearly equals zero. For 

 our data a value of 2. 24 was selected for k. The data were then trans- 

 formed /by 



y = Sinh 



r + c 



2c 



since we wished the transformation to be applicable to sets of data 

 with low catch rates. For comparison, the much simpler logarithmic 

 transformation commonly used when the standard deviation is propor- 

 tional to the mean / y - log (r + 1) / was also applied to the same sets 

 of data. 



z 

 < 



LlJ 



FIG. 2 RELATION BETWEEN MEAN AND FOR EIGHT SETS OF 

 UNTRANSFORMED LONGLINE CATCHES. EACH POINT REPRESENTS 

 THE MEAN AND 6 FOR A SERIES OF 2,000 HOOK SETS AT 

 ONE LOCALITY IN ONE MONTH 



5/ This follows Ansconnbe 1949, formula 7, C is given the value of 

 0. 2 confornaing with our low value of k; r is the individual catch. 



8 



