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accompanied by trends concerning the size of fish, in that a three-year- 

 old fish today may be smaller--due to lack of food--than a three-year-old 

 fish of five years ago. Such information, and its degree of importance, 

 has not been studied. 



5. Fish behavior. Fishermen have many opinions concerning the behavior 

 characteristics of fish. They feel that such characteristics are \/ery 

 important, particularly with relation to effort coefficients. 



For example, domestic draggermen have found that yellow-tail flounder 

 tend to scatter when a certain number of vessels concentrate in an area. 

 Whereas one vessel can fish the same ground all day, the presence of several 

 seem to cause the fish to scatter after a few tows. If this is true, 

 fishermen feel that stock abundance may be incorrectly estimated according 

 to effort calculations: increased effort may produce less yield, but not 

 for reasons of depletion so much as behavior. 



In addition, it has been found that certain species are attracted by 

 bottom disturbance while others are repelled. During the last few years 

 it was found that affixing a large chain to the bottom rope of a trawl 

 attracted yellow-tail through stirring up the sand during the net's passage. 

 With such a chain, then, the effort coefficient of a vessel would alter by 

 increasing. Had such information been utilized, yellow-tail depletions 

 might have been predicted earlier. 



Although such issues may be of questionable importance in relation to 

 overall assessments, the fact that behavior characteristics of fish popu- 

 lations have not been investigated through a coordinated program is dis- 

 turbing to members of the fishing industry. 



