than the metal tags, and we were not planning 

 to use its radioactive capability. 



The numbers of menhaden that died in each 

 tagging experiment are shown in Table 2. Tag 

 Type A caused the most deaths. The combined 

 loss from dying and shedding are shown in Table 

 3. More menhaden tagged with Types A and B 

 died or shed their tags than did those with Type 

 C. From these trials, Type C was selected for 

 menhaden tagging studies. 



Menhaden that died during the experiment 

 and those that survived until the end of the 10- 

 week period were examined for an apparent 

 cause of death. At the end of the 10-week pe- 

 riod, all survivors had healed incisions that were 

 faintly visible as slight depressions without 

 scales. Recipients of Type A tags dying during 

 the study had enlarged open wounds and some 



Table 2. — Number of dead Atlantic menhaden in each 



tagging experiment at the end of 5 biweekly periods. 



[Number of fish in each lot in parentheses.] 



T 



Figure 2. — Inserting a metal tag into the body cavity 

 of young Atlantic menhaden. 



Table 3. — Number of tags lost from experimental groups 



by death and shedding at the end of 5 biweekly periods. 



[Number of fish in each group in parentheses.] 



tags protruded. Types A and B tags found in 

 dead fish or loose on the bottom of the tanks 

 were corroded. The peritoneum did not heal in 

 any incised fish. Muscles were discolored near 

 Types A, B, and D tags, and the tags were im- 

 bedded in the mesenteries near the cardiac and 

 pyloric stomachs. Types A and B tags usually 

 were enveloped with tissue. Types C and D tags 

 were better for they apparently caused less ir- 

 ritation. 



We were unsuccessful in our attempts to tag 

 smaller menhaden, 75 to 90 mm fork length, in 



516 



