178 



Fishery Bulletin 97(1), 1999 



For the first experiment, ?ili,A,t(>))=0 because inter- 

 nal tags (tag A)were inserted into the shark's body 

 cavity and were not shed, except under very unusual 

 circumstances. For the same reason, although three 

 recaptured school sharks appeared to have shed their 

 internal tags (rows 9 and 21, Table 1), these events 



were actually due to failure to detect the tag upon 

 recapture. Consequently, both tags were assumed to 

 be present for these recaptures. Also, tag shedding 

 rates of white and gray Petersen discs were estimated, 

 singly or in combination, to examine their possible 

 differences (Table 3). Data on X(i,A,t( i>>(Roto tags) 



