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