An Overview of Taiwan Distant Water Purse Seine Fishery-2001
Ren-Fen Wu1
1 Overseas Fisheries Development Council of the Republic of China
19, Lane 113, Roosevelt Road, Sec. 4 Taipei, Taiwan 106
SCTB15 Working Paper
FTWG–8
An Overview of Taiwan Distant Water Purse Seine Fishery - 2001
Ren-Fen Wu
Overseas Fisheries Development Council of
the Republic of China
19, Lane 113, Roosevelt Road, Sec. 4 Taipei, Taiwan 106
Tel: 886-2-2738-1522 FAX: 886-2-2738-4329
JULY, 2002
This paper is prepared for the 15th meeting of the Standing Committee on Tuna and Billfish (SCTB) held in Honolulu, U.S.A, July 22-27, 2002. Document not to be cited without permission of the authors.
Introduction
Tuna purse seine fishery was introduced into Taiwan in 1982 and developed
rapidly in late 1980’s. Since early 1990’s, Taiwan has become one of the most
important purse seine fishing countries in the Western and Central Pacific Ocean, in
terms of catch and fleet.
The number of Taiwanese purse seiners reached historical peak of 45 in 1992,
and had maintained at 42 from 1995 to 2000, reducing to 41 last August after one
vessel sold to foreign company.
The average annual production from this fishery during 1997-2001 is about
210,000 MT. In 1998, the production reached historical high of about 260,000 MT,
after then the production has been kept at a level of between 200,000 MT and 230,000
MT.
The major fishing grounds are located in the EEZ of FFA member countries,
including Papua New Guinea, Federated States of Micronesia, Solomon Islands and
Kiribati, and nearby high sea areas.
Fishing grounds – set distribution
Probably due to the water temperature was lower than normal in Eastern Pacific
Ocean, the set distribution of Taiwan purse seine fishery in 2001was more eastward
than in 2000, with major fishing grounds of Taiwan purse seine fishery locating in the
area around 8°N-10°S and 145°E-180°E (Fig.1), including the EEZ of Papua New
Guinea, Federated States of Micronesia, Nauru, Kiribati, Marshall Islands, and
Solomon Islands as well as the nearby high sea areas.In January 2001, most of
Taiwanese purse seiners stayed in the EEZ of PNG and FSM and the nearby high
sea area, concentrating in the waters of FSM and nearby high sea area and began
shifting eastward in February (Fig.2).
In the beginning of the second quarter, the majority of these vessels operated in
the area around 160°E-170°E and 6°N-2°S. About 80% of the fleet shifted to the EEZ
of Kiribati (fig 3).
In July, There were about 35 purse seiners operated in the EEZ of Kiribati. Some
of them even shifted into the 170°W-175°W and 4°N-8°N area (fig 4).
In the last quarter of 2001, most of the purse seiners returned to the waters of
PNG and Nauru. Some vessels moved southward to the EEZ of Solomon Islands in
November and December (fig 5).
Catch and catch composition
After 1998, the annual production of Taiwan distant water purse seine fishery
was over 200,000 MT. Moreover, both the productions in 2000 and 2001 were over
230,000 MT (fig 6).
In terms of catch composition, skipjack and yellowfin tuna accounted for about
98% of total catch during 1997-2001 (table 1), and bigeye tuna just accounted for a
small portion.
Because of price difference between skipjack and bigeye tuna, with the price of
bigeye tuna higher than the price of skipjack by about 30 to 50 U.S dollars per MT,
buyers will prefer separating different species from of the catch when transhipping.
School types
Taiwanese purse seiners mainly targeted on unassociated schools and the rate of
setting on artificial log has decreased after the peak of 1999 (fig 7, table 2).
The catch compositions vary greatly along with the sets on unassociated, natural
log and artificial log schools (fig 8). It is obviously that the percentage of yellowfin
tuna caught by unassociated school set was higher than that of the other two school
types.
Observer program
The Fisheries Administration launched the first observer program for purse seine
fishery in 2001 and dispatched one observer to a sample vessel from Aug. 27th to Nov.
20 2001 to collect information on the use of new equipment, catch composition, school
types, discards and by-catch. Being aware of the importance of it, FA has decided to
continue and expand the observer program.
During the program period, the observer observed 2 fishing trips with areas of
operation mainly concentrated around 165°E-175°W and 4°N-4°S(EEZ of Kiribati).
The result will be discussed in more details as follow:
1. Catch composition and school types:
During the two fishing trips, the total catch and the number of sets were 1,521
MT, including skipjack 816 MT and yellowfin tuna 705 MT. The rate of setting on
artificial log of this sample vessel was about 26%, lower than the rate of sets on
unassociated school (74%).
The average length of skipjack caught by sample vessel was about 46 cm, and it
seemed that the skipjack caught by sets on unassociated school (averaged length 47.8)
was larger than caught by artificial log (averaged length 45.4) (Fig. 10).
2. Discards:
There were 9 sets with discards at sea in the first trip, of which 6 sets were on
artificial log (75%) and the rest on unassociated school and 16 sets with discards at sea
in the second trip, of which 11 sets were on artificial log (91.7%) and the rest on
unassociated school.Empty set
There were 13 empty sets in the first trip, all were on unassociated school and the
rate of empty set was 50%. In the second trip, there were also 13 empty sets and all on
unassociated school, the rate of empty set was 43%.By catch:
According to the observer’s record, one green turtle was caught in first fishing
trip and one leatherback sea turtle and one pygmy killer whale were caught in the
second fishing trip. They were all released alive.
.
Fig. 1 Comparison of set distribution of 2000 and 2001
Fig. 2 Comparison of set distribution of 1st quarter of 2000 and 2001
Fig. 3 Comparison of set distribution of 2nd quarter of 2000 and 2001
Fig. 4 Comparison of set distribution of 3rd quarter of 2000 and 2001
Fig. 5 Comparison of set distribution of 4th quarter of 2000 and 2001
Year SKJ YFT BET OTHERS
1999 78.62% 20.53% 1.65% 0.00% 2000 82.70% 16.40% 0.81% 0.09%
2001 79.09% 19.87% 0.99% 0.05%
0
50,000
100,000
150,000
200,000
250,000
300,000
1997 1998 1999 2000 2001
Year
Cat
ch
OTHERS
BET
YFT
SKJ
Fig. 6 Comparison of catch during 1997-2001 period
Table 1 Comparison of species composition during 1997-2001 period
1997 1998 1999 2000 2001
Unassociated 43.60% 64.44% 38.32% 67.79% 70.68%
Natural Log 33.11% 24.53% 27.94% 8.01% 9.99%
Artificial log 9.64% 5.54% 30.72% 22.93% 16.79%
0
1000
2000
3000
4000
5000
6000
7000
1997 1998 1999 2000 2001
Year
Set Artificial log
Natural log
Unassocaited
Fig. 7 Comparison of set number of different school types during 1997-2001 period
Table 2 Comparison of school types during 1997-2001 period
Year
School type
0%10%20%30%40%50%60%70%80%90%
100%
Unassociated Natural log Artificial log
School type
%
YFT
SKJ
Fig. 8 Comparison of catch composition of different school types in 2001
Fig.9 Locations of sample vessel
01020304050607080
28 32 36 40 44 48 52 56 60 64 68 72
FK length(cm)
No. FAD
Unassociated
Fig.10 Comparison of FK-length of skipjack caught by different school types