Tagging of Skipjack — Yamashita and Waldron 
345 
TABLE 1 
POFI Skipjack Recoveries with White California Type G Tag 
order 
OF 
RECOVERY 
WEIGHT RANGE 
OF SCHOOL 
AT RELEASE 
DATE 
TAGGED 
DATE 
RECOVERED 
DAYS 
OUT 
DISTANCE 
TRAVELED 
WEIGHT 
AT RE- 
COVERY 
REMARKS 
Lbs. 
Miles 
Lbs. 
1 
5-10 
6/1/55 
7/12/55 
41 
0 
3-4 f 
Recaptured from one 
2 
6-8 
6/8/55 
7/12/55 
34 
0 
3-4 ( 
school 
3 
3-5 
7/20/55 
7/26/55 
6 
40 
4 
4 
5-8 
7/18/55 
7 / 30/55 
12 
0 
6 
5 
3-6 
8/22/55 
8/24/55 
2 
6 
31/2 
Found in stomach of long- 
line-caught 189-lb. yel- 
lowfin 
6 
3-5 
7/20/55 
8/28/55 
39 
17 
4 
7 
4 
8/17/55 
8/17- 
8/26/55 
0-9 
o(?) 
Tag only found in stomach 
of longline-caught 190- 
lb. yellowfin 
8 
3-5 
8/25/55 
8/25- 
9/1/55 
0-7 
0 
4 
Found in stomach of long- 
line-caught 209-lb. big- 
eye 
9 
4-5 
8/8/55 
8 / 29/55 
21 
14 
3( 
Recaptured from same 
10 
4-5 
8/8/55 
8 / 29/55 
21 
14 
31 
school 
il 
4-5 
8/8/55 
10 / 29/55 
82 
9 
41/2 
12 
51/2-91/2 
5/25/55 
2/1/56 
252 
30 
14 
healed completely and was marked only by a 
black spot on the skin (Fig. 4). Adhesion be- 
tween the flesh and the plastic held the tag 
in place. 
Movement: All of the skipjack recovered 
were small (3 to 10 lbs.) when tagged. They 
showed surprisingly little movement, all of 
them being recaptured within 40 miles of the 
point of release (Fig. 3 and Table 1). There 
was no inter-island movement of tagged fish. 
The probability of recovery of tagged skip- 
jack in offshore waters (beyond 50 miles from 
land) is low because very little fishing is done 
in this area. However, each of the main Ha- 
waiian islands has fisheries within 20 miles of 
shore, so this lack of evidence of inter-island 
movement cannot be attributed to the dis- 
tribution of fishing effort. 
Two of 39 fish (Table 1, recoveries 9 and 
10) released in one group were recaptured 3 
weeks later from a single school, indicating 
that a school of skipjack retains its identity as 
a unit for some time. Recoveries 3 and 6 
tagged on the same day and from the same 
school, may provide an example of the use- 
fulness of this hypothesis. This school may 
have traveled 63 miles between July 20 and 
August 28, 1955; 40 miles to where No. 3 was 
retaken, and 23 miles back to where No. 6 was 
retaken. Similarly, the group in which recov- 
eries 9, 10, and 11 were released may have 
traveled a minimum of 37 miles between 
August 8 and October 29, 1955. These are 
straight-line distances, and in all likelihood a 
much greater distance was covered during 
this period. 
Growth: Information concerning the rate of 
growth of skipjack was gained from a tagged 
fish which weighed 14 pounds when recov- 
ered after 252 days (8.4 months) at liberty. 
Based on the average weight of fish (7 
pounds) and the size range of fish (5.5 to 
9.5 pounds) in the school at the time of re- 
lease, a comparison may be made with the 
growth rates obtained by Brock (1954) in his 
length frequency studies. If this tagged fish 
was at the lower end of the size range (i.e., 
5.5 pounds) when tagged, it grew at the rate 
of about 1.0 pound per month. This closely 
approximates Brock’s estimate of 1.2 pounds 
