LENARZ: MESH RETENTION OF LARVAE 



Table 1. — Catches of northern anchovy larvae by type 1 (0.55-mm mesh) and type 2 



(0.333-nim mesh) nets for each sample. 



Sli = 



m 



^ WlifcW2jfc 



k = l 



« 



^ n2ik 



k = l 

 where m — number of samples. 



However, if the assumption of independence 

 of ejfc is violated, (2) is not the least squares 

 estimate of Sij. A form of violation of the as- 

 (2) sumption which is common in plankton sampling 

 is that the error term is proportional to V^2jk. In 

 this case the least squares estimate of su is given 

 by Cochran (1963) as 



841 



