FIGURE 26 - SMALL ROCKFISH, 3/4 TO 3 1/2 INCHES IN LENGTH, WERE PREDOMINANT IN THE 

 STOMACH CONTENTS OF ALBACORE. UP TO 167 WERE TAKEN FROM ONE TUNA. 



T agginK of Albacore 



Tagging was carried out aboard the John N. Cobb in an effort to gain in- 

 formation concerning the migratory patterns of the albacore off the coasts of Ore- 

 gon, Washington and adjoining regions. Unfortunately, a successful method of tag- 

 ing tuna has not yet been developed; hence, the tags and the procedure used were 

 of a purely experimental nature. 



Two types of plastic tags were used, the Peterson plastic disc tag and 

 a plastic stirLp tag. Three hundred and ninety-seven albacore were tagged with the 

 Peterson-type tag which consisted of two circular 9/l6-inch-diameter discs, one 

 yellow and one red. These discs were placed on each side of the second dorsal fin 

 and v;ere joined together by a nickle pin inserted through the anterior base of the 

 fin; others were attached to the caudal keel. Thirty-five albacore were also tagged 

 with a red and green plastic strip tag, 5/8-inch long and l/Q-inch wide. However, 

 these tags were difficult to affix as the narrow plastic strip offered little lever- 

 age to the thumb when the second dorsal fin base was pierced and the shaiTD edges 

 of the tag cut into the albacore quite readily. 



The troll-caught fish selected for tagging were generally those that 

 showed only slight hook damage and little bleeding. Rough handling of the fish 

 was minimized by landing the albacore on a piece of cotton netting or on a sheet 

 of rubber stretched across the top of a fish box. The albacore were placed in a 

 canvas-lined tagging cradle immediately after boating and hook removal. Many al- 

 bacore vibrated excessively while being tagged. This vibration could be somewhat 

 inhibited if one hand was cupped over the head of the fish so that the thumb and 

 the forefinger rested lightly on the eyes. With few exceptions, all tagged alba- 

 core when released swam away rapidly, some sounding at once. 



34 



