4. Speed of attachment. The tag should be 

 suited to quick attachment with the mini- 

 mum possible handling of the fish. 

 Herring lose their scales from slight 

 finger pressure, and as Hodgson (1957) 

 noted, a herring losing 50 percent of its 

 scales will not survive. 



5. Durability . The material of the tag should 

 be sufficiently durable to resist the 

 chemical action of sea water and should 

 retain its code markings in a legible 

 manner. 



NYLON PLUG 



CODED VINYL TUBING 



ASSEMBLED TAG 



Nontoxic yellow polyvinyl chloride tubing of 

 the conventional "spaghetti" appearance was 

 chosen for the body of the tag. The tubing had 

 an outer diameter of 0.051 inches and an inner 

 diameter of 0.027 inches. The length was set 

 at 2.125 inches. The thick dorsal musculature 

 of the herring midway between the nape and the 

 insertion of the dorsal fin was selected as the 

 point of attachment. To avoid knotting or tying 

 the ends of the tubing after the tag had been 

 inserted through the fish, a small nylon V- 

 shaped plug was devised as a seal. Translu- 

 cent nylon rod 0.045 inches in diameter and 1 

 inch long was chosen for the seal. The ends 

 of the rod were cut to a point, and the rod 

 was then heated and bent to an angle of approxi- 

 mately 45 degrees. When the vinyl tubing was 

 inserted with a hypodermic needle through the 

 dorsal musculature of the herring, the nylon 

 rod afforded a quickly applied friction seal 

 that firmly joined the free ends of the tubing 

 and formed the tag into a teardrop shape. 



The tags were coded with two- and three- 

 letter permutations of commercial Gothic 

 letters. The letters were engraved in the tag 

 and were filled with black vinyl ink. The tag 

 was assembled as shown in figure 1. The tags 

 were coded in lots of about 500 each. Later, 

 when only a portion of a coded lot of tags was 

 used in the field, the remainder was re-coded 

 by adding a dashed line. 



Herring for tagging were procured from 

 a fisherman at the site of capture and placed 

 in a 3- by 4-foot oblong by 5-foot deep holding 

 pocket made of 3/16-lnch bar measure nylon 

 mesh (fig. 2). Dip nets were used initially to 



NO. 14 HYPODERMIC NEEDLE 

 MODIFIED TO ACCEPT TAG 



5. 



LOADED TAGGING NEEDLE 



JUVENILE HERRING 

 WITH TAG IN PLACE 



Figure l.--Component parts and position of Maine 

 sardine tag. 



transfer the fish from the fisherman's net to 

 the holding pocket, but were subsequently re- 

 placed with polyethylene pails because the 

 netting scraped scales from the struggling 

 fish. Fish were removed from the holding 

 pocket, about 15 at a time, in 10-quart poly- 

 ethylene pails. Two men did the actual tagging: 

 one man held the fish and inserted the loaded 

 needle through the dorsal musculature, and 

 the second man drew the needle through the 

 herring's body, leaving the tag in position, 

 and forced the free end of the nylon plug into 

 the open end of the polyvinyl tubing. The tagged 

 fish was then placed in a second holding pocket 

 for release with several hundred tagged fish 

 as a school. 



