A RAPID METHOD OF TAGGING FISH 



By Henry M. Sakuda, Aquatic Biolosist, Division of Fish and Game, Honolulu, Hawaii 96813 



A unique tagging procedure has been devised 

 that requires but two persons, is rapid, and pro- 

 vides accurate permanent records that can be re- 

 checked as many times as necessary. Methods used 

 up to this time require several men, and the 

 records obtained are only temporary and often 

 inaccurate. 



The Division of Fish and Game, Department of 

 Land and Natural Resources, State of Hawaii, is 

 now tagging akule (bigeye scad), Traehurops 

 crumenophthalmus, for studies of growth and 

 migration. 



Generally, our tagging method is an extension 

 and modification of fish measuring tecluiiques de- 

 scribed by Wollaston (1928), Thompson (1929), 

 and recently by Joeris (1959) , who used a measur- 

 ing board to which plastic strips (exposed or out- 

 dated X-ray film strips) were attached. The fish 

 is laid on the measuring board with its snout 

 against a stopblock, and the length is recorded by 

 punching a hole in tlie film. Tlie method described 

 iiere involves the same general technique except 

 that X-ray films are also specially prepared to 

 hold and dispense tags in nmnerical order and to 

 retain paired information on tag niunbers and 

 length of fish tagged. 



The adaptation of X-ray film to fulfill the 

 method's requirements was accomplished by paint- 

 ing stripes on the film and placing a tag with each 

 stripe. It involves the association of tag, tag num- 

 ber, and length of fish represented by a perfora- 

 tion on the film in the striped area. To adapt the 

 film, each exposetl X-ray film plate (obtained 

 from local hospitals without cost) is prepared 

 with several equally spaced horizontal 12.5-mm. 

 wide yellow stripes spray-painted through a tem- 

 plate on the film. At tiie end of each stripe the film 

 is slit to hold the modified plastic internal anchor 

 tag used on T. cfumenophthalmm (Sakuda, 1966) ; 



1 The Bureau of Commercial Fisheries provided support under 

 P.L. 88-309, Project No. H^-R-1. 



Published March 1968. 



the tags are in numerical order from the top to 

 the bottom of the film. The tag numbers are M'rit- 

 ten on tlie first and last stripes with a china-mark- 

 ing pencil (fig. 1). The size of the X-ray film, 

 number of stripes, and spacing between stripes, 

 depend on the size of fish to be tagged. For akule, 

 a plate 36.0 by 43.2 cm. is used; it carries 15 

 stripes. Other types of tags (e.g. dart, spaghetti, 

 or Petersen disk) may be attached to the tagging 

 plate with masking tape. 



The tagging plates require a flat surface for 

 their use; a table with a 12.5-nun.-thick cork top 

 and a stopblock along one edge served this purpose. 

 The tagging plate is butted firmly against the 

 stopblock and securely pinned to the table, and the 

 immobilized fish is laid along the horizontal stripe 

 with its snout against tlie stopblock. Length is 

 then recorded by perforating the stripe with a 

 dissecting needle. The corresponding tag at the 

 end of the stripe is then removed from the plate 

 and inserted into the body cavity tiirougli a small 

 incision on tlie side of the fish. 



To minimize handling of the fish, a holder is 

 also used in tlie tagging. It is constructed of 1.5- 

 mm.-thick clear plastic sheet, 30.5 cm. long and 6.3 

 cm. wide, with a 12.5-mm. -wide lengthwise slot to 

 match the horizontal stripe on the tagging plate. 

 When placed over the tagging plate, the holder is 

 manipulated to center the fish over the stripe and 

 in position for the length measurement to be 

 punched. A 6.2-mm.-thick sheet of polyurethane 

 foam, 23.0 cm. long and 6.3 cm. wide, is glued to 

 the upper surface of the holder to provide a soft, 

 moist bed for the fish during tagging. A piece of 

 nylon window screen the size of the liolder is 

 glued to the undersurface of the holder to reduce 

 adhesion of the holder to the tagging plate. Fish 

 length is recorded by punching a hole into the 

 tagging plate through the foam sheet and screen. 



The tagging plates are stored in numerical 

 order in cardboard boxes painted with epoxy 

 resin. Upon completion of a day's tagging, the 



FISHERY bulletin: VOL. 6 6, NO. 3 



573 



