Tagging of Skipjack — YamASHITA and WALDRON 
343 
Fig. 1. California type G tag and tagging needle. 
Legend is on inner tubing only; serial numbers on 
inner and outer tubing. 
Most of the skipjack tagged as described 
above sounded immediately upon release. On 
a few occasions they were seen to lead fish 
from the accompanying school away from 
the stern of the vessel. While some tagged 
fish left the school when released, there were 
indications that others remained in the same 
school from which they were caught. In one 
instance a fish released with a white type G 
tag was observed accompanying the vessel 
with part of the school for 414 hours. 
RELEASES 
Between May, 1954, and July, 1956, 1,961 
skipjack were tagged with the California type 
G tag and released in Hawaiian waters 
(Fig. 2). 2 
Most of the releases were within the area of 
the Hawaiian skipjack fishery; a few were re- 
leased outside this area. This release pattern 
was followed in order to (1) establish the rate 
of recovery within the fishery, (2) study the 
movements of skipjack within the fishery, 
and (3) ascertain the direction from which 
skipjack approach Hawaiian waters. 
It should be pointed out that the tagged 
fish were smaller than the usual size (18-22 
pounds) composing the season’s commercial 
landings. Eighty-five per cent were 10 pounds 
or smaller, 14 per cent between 11 and 20 
pounds, and only 1 per cent larger than 21 
pounds. The small percentage of releases in 
^ In addition, 20 skipjack were tagged with white 
type G tags and released in the vicinity of the Line 
Islands, and 12 with blue type G tags northeast of 
Midway Island. 
the larger size categories is due partly to the 
difficulty in handling these fish, and partly to 
the general scarcity of large fish when most 
of our tagging was done. 
PUBLICITY PROGRAM 
Publicity is an important part of most 
tagging programs, because one way to maxi- 
mize the returns is to minimize the loss of 
tags recovered but not noticed by persons 
unaware of the program. We conducted per- 
sonal interviews with skipjack fishermen on 
all islands and distributed posters to major 
fishing companies, fishing supply centers, and 
ports throughout the Hawaiian Islands. Fish- 
ermen were also informed of our tagging 
activities through radio broadcasts, trans- 
mitted by POFI vessels during their cruises in 
Hawaiian waters, and through informal let- 
ters. Also, wardens of the Hawaiian Division 
of Fish and Game stationed on the various 
islands were furnished photographs of tagged 
skipjack, together with standard recovery in- 
formation forms. Because of the distinctive 
appearance of the tag, the publicity program, 
and the extensive handling of individual fish 
(when caught, during stowage and unloading 
of catch, and during butchering at the can- 
nery), the possibility of loss of tags through 
nonrecognition of tagged fish was considered 
negligible. 
Rewards for the return of tags were not 
part of the recovery program. Instead we pur- 
chased the tagged fish at a price slightly above 
the market value. A letter giving pertinent in- 
formation was also sent to the person, or 
persons, involved in the recovery. 
RECOVERIES 
Of the 1,961 skipjack tagged and released, 
9 were recovered by the commercial pole- 
and-line fishery and 3 from the stomachs of 
large longline-caught tunas between July, 
1955, and February, 1956. The areas of release 
and recapture for these 12 skipjack are shown 
in Figure 3 and listed in Table 1. The low rate 
of recovery, 0.6 per cent, may be attributed in 
