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A review of the fishing capacity of the longline fleets of the world


Peter Makoto Miyake
Scientific Adviser

Federation of Japan Tuna Fisheries Cooperative Associations (Japan Tuna)
3-3-4, Shimorenjaku, Mitaka-shi
Tokyo 181-0013, Japan
E-mail: miyake@sistelcom.com

ABSTRACT

This paper provides estimates of the size of the large-scale tuna longline fleet of the world, and discusses it in terms of the tuna resources available to it. Large-scale longliners are defined as those with gross registered tonnages greater than 200 or overall lengths greater than 35 metres, equipped with freezers making it possible for them to market their catches as "sashimi-grade" fish. Lists of the vessels authorized to fish in the areas of responsibility of the various regional fishery management organizations ("positive lists") were used to make the basic estimates of fleet sizes. Duplication of vessels in the positive lists, because they fished in more than one ocean, was eliminated in estimating the total number of vessels of the world fleet.

Logbook data from Japanese longliners were used to estimate the numbers of Japanese longliners actively engaged in fishing in the three oceans, and this estimate was compared with the official list of licensed longliners. It is obvious that vessels frequently fish in more than one ocean during the same year and that not all the longliners licensed for a particular ocean fish in that ocean.

Activities of illegal, unreported and unregulated (IUU) vessels and the work by the Organization for the Promotion of Responsible Tuna Fisheries (OPRT) were reviewed. The fleet size publicized by the OPRT, rather than the numbers of vessels in the positive lists, was used for its members. This resulted in the addition of 30 IUU vessels, assumed to be still in existence, and the total number of large-scale longliners was estimated to be 1 622.

The catches of commercially-important species of tunas by large-scale longliners were estimated to be roughly 400 000 tonnes in 2001. Therefore, the average catch per vessel per year was 240 tonnes, which is close to the current economic break-even point. It appears that almost all the tuna stocks in the world are now harvested at levels close to those corresponding to the maximum sustainable yields, if not in excess of those levels. If the fishing patterns and fishing behavior of longliners remain at the present levels, any increase in longline fishing capacity would have a negative impact on tuna stocks. On the other hand, the same levels of catches could most likely be achieved even with a smaller fleet size. A reduction of the fleet size would make the longline fishery more competitive with the other fisheries, provided the sizes of the other fleets were also reduced. Some elements that may affect this situation are:

1. Introduction

This paper reviews the current fishing capacity of the large-scale tuna longline fleets of the world. Fishing capacity, or simply "capacity", is difficult to define, but is essentially the mechanical and economical ability of a vessel or a fleet to catch fish. Fishing capacity is not to be confused with fish-carrying capacity, which is useful in studies of purse-seine and pole-and-line fisheries, but not in studies of longline fisheries. It is even more difficult to estimate the total fishing capacity of the longline fleets of the world. Nevertheless, it is important, for purposes of management, to have estimates of the fishing capacities of the various fishing fleets.

Compilation of a list of large-scale longline vessels is not straightforward, due to the following difficulties:

Those difficulties are discussed in the following sections, and some solutions are offered. While estimating fleet size, it is imperative to consider illegal, unreported and unregulated (IUU) vessels and the management policies adopted by the various countries for their longline fleets. Although management is to be covered by other contributors to this collection in this paper past national and international management of fleet sizes is briefly discussed, in respect to the estimation of the total fleet size.

2. Longline fleets of the world

2.1 Distribution of fisheries and size of fishing vessels

Longlining for tunas and tuna-like species takes place in tropical and temperate ocean waters all over the world. In general, longline fisheries exist wherever tunas and billfishes occur. Historical developments in longline fishing and processing longline-caught fish are discussed by Miyake (this collection) and by Miyake, Miyabe and Nakano (2004). The fleet has consisted of various-sized vessels, from canoes to motherships of more than 1 000 gross registered tons (GRT). Two categories, large-scale and small-scale[30], are defined.

2.1.1 Small-scale longliners

Small-scale longliners are further divided into the following groups:

2.1.2 Large-scale longliners

These vessels are equipped with freezers (often super- freezers that freeze and maintain the fish at temperatures below -45°C). Generally, the vessels are more than 200 GRT (i.e. definitely more than 24 metres in overall length (LOA) - see later section). However, after the positive list system (Section 2.4) was adopted, some boats less than 24 metres in LOA, but equipped with super-freezers, have been constructed. These vessels are not considered to be large-scale longliners in this report, however, as information on the activities of these vessels is not available. A trip of a large-scale longliner lasts from several weeks to more than one year. Often fishing takes place far from the vessels home ports, and crew members are rotated by air. This fleet targets sashimi-quality fish.

Most of the vessels of this type that target tunas are owned by interests in Japan, China, the Republic of Korea, the Taiwan Province of China and, to a lesser extent, the Philippines. This category also includes vessels engaged in illegal, unreported or unregulated (IUU) fishing, and vessels flying "flags of convenience" (FOC).

There are also longliners that target swordfish. These vessels do not need to have super-freezers, and many of them, even those of more than 250 GRTs, use ice to preserve their catches. Swordfish longliners are most often registered in Spain, Portugal, Italy, the United States or Canada.

Unfortunately, not all vessels can be easily assigned to one of these categories, as some of them have characteristics of more than one category. This is discussed further in Section 2.2.

2.2 Criteria for classifying sizes of fishing vessels

In this study, the fleet statistics are composed basically from lists of registered vessels (Section 3.1). Most such lists do not contain essential information, such as the target species, method of preservation of the catch, etc. In order to identify the large-scale tuna longliners, a single criterion would be most useful. The parameters that are available for most of the longliners are GRT and/or LOA

The LOA is the perpendicular distance between the bow and stern of the vessel at the main deck. The GRT is the volume of space within the hull and enclosed spaces above the deck of a vessel that are available for cargo, stores, fuel, passengers and crew. One ton is equivalent to 100 cubic feet (2.83 cubic metres). The International Maritime Organization set the international standard for GRT, but the interpretation of enclosed space can vary from one country to the other. Therefore, when specification is given in GRT, it is not clear how this is measured.

FIGURE 1
Relationship between LOA and GRT reported for tuna longline vessels in three oceans

The relationship between LOA and GRT for the tuna longliners for which information on both parameters is available in the positive lists (see later sections) is shown in Figure 1. The positive lists include only vessels more than 24 metres in LOA, and hence most of the points in the figures are greater than 24 metres. Also those of 1 000 or more GRT were excluded, as they are mostly mothership-type vessels or cargo vessels (possibly exclusively for tuna). The wide variation observed in this relationship is due mostly to the different measurement standards applied by the various countries.

Considering all these complex elements, the following criteria were adopted to separate out large-scale longliners:

However, some flexibility was adopted in the final decision. For example, a higher GRT criterion was used for the longliners of the Taiwan Province of China that are fishing in the eastern Indian Ocean or the western Pacific Ocean. All the longliners of the Republic of Korea were considered to be large-scale longliners, in accordance with a suggestion by government officials.

2.3 Regulation of fishing fleets

The management of fleet size has developed more for large-scale longliners than for any other type of tuna-fishing vessel. When Japan initiated a licensing system for tuna longliners during late 1940s, a limited-entry system, based on the total GRT of the fleet, was already established. During the period of development of the fishery the total allowable GRT was increased from time to time, and the fishing fleet expanded until the 1970s. Thereafter, no increase has been allowed and, for the first time, a reduction in the total licensed GRT was introduced in 1982. It was reduced again in 1999, to conform to the FAO International Plan of Action for the management of fishing capacity.

A licensing system similar to that of Japan, with limited entry and restrictions based on total GRT, has been adopted by other countries with large-scale longliners, e.g. the Republic of Korea, the Taiwan Province of China, the Philippines and China. However, the conditions and procedures have differed among nations. For example, the Republic of Korea began limiting its total licences during the 1980s, while China and the Taiwan Province of China increased their total licences (in numbers of vessels and GRT) until 2003. Both of these, however, declared that no more increases would be allowed.

Many other countries (e.g. Panama, Honduras, Belize, Vanuatu and Cambodia), on the other hand, continued to issue licences without any restrictions. A detailed discussion of this can be found in Section 2.4.

In the case of Japan, all the vessels of more than 80 GRT were formerly considered to be large-scale longliners. This limit was changed to 120 GRT in 2002. Further restrictions were placed on vessels in accordance with upper limits (e.g. 500, 440, 380, 260 and 200 GRT) and areas of operation.

All longliners of the Republic of Korea are considered to be large-scale vessels.

For the Taiwan Province of China, 50 GRT is the criterion adopted by the governing authorities to separate the coastal and distant-water longliners. However, the vessels of less than 200 GRT are mostly fresh-fish vessels, even though they may fish in distant waters, so, for that reason, 200 GRT was used as the criterion for separating small- and large-scale longliners.

Most of the Japanese large-scale longliners are equipped with super-freezers, whereas super-freezers are not often found on vessels of the Taiwan Province of China, with GRTs less than 500. However, a 500-GRT vessel of the Taiwan Province of China is equivalent to a Japanese longliner of a much lesser GRT, as the standards for measuring GRT are different for the two fleets.

2.4 Flag of Convenience and IUU fleets, and international regulations

When a vessel is registered in a country of open registry it is said to fly a "flag of convenience" (FOC). FOC vessels, owned mostly by residents of Asia, existed as early as the 1960s. As there were already limited-entry systems in some countries, when an owner acquired a new fishing vessel, he would lose the licence for the one that it replaced. Often, however, such vessels were "reflagged" to countries with open registry. Also, FOC registration was used to avoid domestic regulations on nationality of crew members, safety requirements, periodic inspections, etc.

During the late 1980s, when regulatory measures such as catch quotas were adopted by the various regional fishery management organizations (RFMOs), some vessel owners, reflagged their vessels to non-contracting countries whose vessels were not subject to the regulations adopted by the RFMOs. This is called "illegal, unreported and unregulated" (IUU) fishing, and the vessels are called IUU vessels. More details are given by Miyake (this collection).

IUU fishing has increased during the 1990s, and various measures have been taken by the FAO and the RFMOs to address this problem. In 2001 FAO adopted the International Plan of Action to prevent, deter and eliminate illegal, unreported and unregulated fishing (IPOA-IUU). ICCAT was the first of the RFMOs to take such measures. It developed a Plan of Action for bluefin tuna, which was later applied to other species, which prescribed the steps to be taken against IUU fishing. The most stringent actions that the ICCAT can take are trade measures, and, indeed, the Commission recommended to the contracting parties that there be a ban on the importation of certain species of tunas from IUU countries.

At the same time, ICCAT identified IUU vessels operating in the Atlantic Ocean, and a list of these was posted on its web site in 1998. Buyers were encouraged to refrain from purchasing fish from these vessels. At that time, it was estimated that there were about 300 IUU vessels. It was not possible to ascertain the precise number of such vessels, as some of them were listed more than once, due to differences in specifications and changes in flags that were constantly taking place.

Shortly thereafter, similar actions were taken by the IOTC, and a list of IUU vessels was developed for the Indian Ocean. Most of the vessels in the Indian Ocean list were also listed in ICCAT's Atlantic Ocean list, but, again, the precise number of duplicated IUU vessels could not be ascertained.

In 2002, ICCAT adopted a new policy, listing the "legal" vessels (positive list), rather than the IUU vessels (negative list). Soon thereafter, positive lists of longliners were adopted by the IOTC for the Indian Ocean and by the IATTC for the eastern Pacific Ocean. The Contracting Parties are responsible for providing lists of legal vessels with LOAs of 24 metres or more that are licensed for fishing in the respective oceans. At the same time, the three RFMOs recommended that all the Contracting Parties prohibit trade with vessels that are not included in the positive lists. The three lists were made available to the public during August 2003. The adoption of the positive list system on a global basis was generally affirmed at the twent-fifth session of the FAO Committee on Fisheries in 2003.

Unfortunately, as soon as the positive-list system was introduced, construction of longline vessels less than 24 metres in LOA, but equipped with super-freezers, began, and some were operating in 2004. Since they are less than 24 metres in LOA, there is no requirement that these vessels be included in the positive lists, and the restrictions regarding vessels not included in the positive lists do not apply to them. Therefore, they are now a new type of IUU vessel. These vessels operate in the same way as do longliners with LOAs greater than 24 metres, and should be subject to the same restrictions as the large-scale longliners.

2.5 Activities of the Organization for the Promotion of Responsible Tuna Fisheries

In accordance with the IPOA-IUU, Japan began to reduce the size of its longline fleet. In 1999, it reduced the total number of licences given to large-scale tuna longliners by 20 percent. At the same time, because of concern about IUU fishing, the Japanese fishing industry created a non-governmental organization, the Organization for the Promotion of Responsible Tuna Fisheries (OPRT), with a membership consisting of tuna producers, tuna marketers and consumer groups. Currently its membership includes ten groups in Japan and one longline-fishing association each from the Taiwan Province of China, the Republic of Korea, the Philippines, Indonesia, China and Ecuador. In addition, Vanuatu and Seychelles longliners are subject to the requirements of the IPOA-IUU through their association with the Japan Federation of Tuna Fisheries Associations.

The initial objective of the OPRT was to persuade the owners of IUU vessels (1) to register them in the countries corresponding to the nationalities of the true owners and to fish legally, observing the regulatory measures and reporting their catches or (2) to scrap them, with some government and/or industry compensation. Since the countries corresponding to the owners' nationalities have limited-entry systems, not all the boats that had been called back could be licensed. Also, when catch quota had been established, the increased numbers of vessels reduced the individual shares, which caused hardship on the owners and fishers. The numbers of large-scale longliners owned by the members of the OPRT are given in Table 1. Between 2001 and 2003, there was an increase of more than 400 longliners. These were the ex-IUU vessels that were called back to the countries corresponding to the owners' nationalities. Therefore, at least these many longliners were removed from the IUU fleet and came, at least in principle, under the control of the RFMOs.

The OPRT estimates that as of June 2004 there are still about 30 IUU longliners. It should be noted that the process of reflagging did not change the total number of large-scale longliners much, except for the loss of an unknown number of vessels that were scrapped. However, it is important that almost all of the longliners are now under the control of responsible governments that are either contracting parties or cooperating parties, entities or fishing entities to one or more RFMOs. It should be noted that the data on fleet size in Table 1 are not current, as older vessels are being scrapped and new vessels are being constructed.

3. Size of the current fleet

3.1 Sources of data

The author of this report repeatedly asked the governments of the countries with major tuna longline fleets to provide him with information on the past and current fleet sizes, numbers of licences issued for each ocean and numbers of longliners actively fishing. Unfortunately, no information was provided by most of these countries, the exceptions being Japan, which provided information on the current status of its fleet, including data to estimate the numbers of active vessels, and China and the Philippines, which provided the total numbers of large-scale longliners currently licensed. Accordingly, the positive lists were used to make a basic estimate of the size of the fleet.

TABLE 1
Numbers of large-scale tuna longliners owned by members of OPRT (as the end of each year)

Country

Group

2001

2002

2003

Japan

Japan Tuna Federation

432

428

420

Distant Waters Association

34

34

39

Near Coast Water Tuna

28

28

25

Fishing Association




Subtotal

494

490

484

Taiwan Province of China


567

562

610

Republic of Korea


-

183

170

Philippines



6

17

Indonesia


-

-

14

China


98

100

105

Vanuatu


-

-

48

Seychelles



-

21

Ecuador


-

-

5

Total


1 159

1 341

1 474

3.1.1 Pacific Ocean

The following sources of information were used:

There was no active RFMO in the western and central Pacific at the time that this report was written, so there is no official list of licensed vessels. (However, the Convention on the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific Ocean (WCPFC) will soon enter into force.) Therefore, the FFA and SPC kindly provided its non-public list of vessels licensed to fish in its waters, which was used for cross-checking the data from other sources. The largest missing component is the fleet of the Taiwan Province of China, as many of these vessels fish in the northwestern Pacific Ocean, which is not covered by any of these lists. The IATTC list often provides the carrying capacities of the vessels, rather than the GRTs.

3.1.2 Indian Ocean

The following sources of information were used:

The vessels of the Taiwan Province of China were not included in the positive list of the IOTC at the time of this study. However, these vessels are listed in the web site of the Indian Ocean Tuna Commission, http://www.iotc.org/, which maintains the list for the purpose of carrying out its own regulations, which allow the purchase of fish only from registered vessels.

3.1.3 Atlantic Ocean

The following source of information was used:

The ICCAT list combines longline and pole-and-line gear in the category "Line and hooks". Among those, Ghanaian vessels were excluded, as they are probably pole-and-line vessels, but the Portuguese fleet, which may include some pole-and-line vessels, is not excluded.

3.2 Data processing

The information from the above vessel lists was combined, and the duplicate entries, to the extent that was possible, were eliminated. The duplications were mostly the result of vessels being licensed to fish in more than one ocean area. In addition, duplications are sometimes the result of obtaining information for the same ocean area from different sources. When vessel names, registration numbers, radio call signs and/or sizes (LOA and/or GRT) matched, they were considered to be the same vessels. When two vessels had the same name, but the sizes and/or registration numbers differed, they were considered to be different vessels, particularly when the names were transcribed from the original languages. In some cases, however, an older boat may have been replaced by a new and larger one with the same name. Therefore, such cases were considered as duplications, if they occurred for a country with limited entries.

On the other hand, if the names of Asian longliners were slightly different, and the other specifications matched, these vessels were considered to be the same. This happens most often when a vessel change its registration from one fleet to another, as the transcription of Chinese characters might differ among fleets.

When the description of a vessel in a list was inadequate, some informed guesswork was necessary. After vessels other than longliners and duplicate records were eliminated, an attempt was made to separate the large-scale longliners from the others. As stated previously, large-scale longliners are those with GRTs greater than 200 tonnes or LOAs greater than 35 metres (Section 2.2), whereas the positive lists include all the longliners with LOAs greater than 24 metres (Section 2.4). Vessels with LOAs between 24 and 35 metres are classified as small-scale longliners. It should be born in mind that there are also many longliners with LOAs less than 24 metres.

The vessels were further classified as tuna or swordfish longliners. Only the vessels that target swordfish most of the time are classified as swordfish longliners; most of these are registered in Spain or the United States. Some of the Asian longliners target swordfish part of the time, depending on the area and/or season; these vessels were classified as tuna longliners. Considerable guesswork, with many assumptions, was involved, as the target species are not specified in any of the vessel lists used.

3.3 Size of the current fleet estimated from the positive lists

The results of the above processing are summarized in Table 2. Only data in the public domain were used in this table. As stated above, there are uncertainties in the estimates. It is more likely that the size of the fleet is underestimated than overestimated, as not all of the positive lists are complete. Also, the data for the western and central Pacific lacks information on vessels of the Taiwan Province of China.

Some of the small-scale vessels have freezing facilities that make them capable of marketing their catches as sashimi-grade fish. In addition, there are several thousand small-scale longliners (Gillett, this collection) and about 30 IUU vessels (Section 2.5) that are not included in this table.

3.4 Licensed vessels vs. active vessels

As explained earlier, the estimated size of the fleet is based on the numbers of licensed longliners. However, not all these vessels are actively engaged in fishing. At any given time, some vessels are undergoing repairs and others have ceased fishing prior to being sold or scrapped. Also, many governments issue licences to vessels to fish in more than one ocean area, and the vessels may or may not fish in all of these ocean areas. Duplication can be eliminated, as explained in Section 3.1, but the number of vessels that actually fished in each ocean area cannot be determined, or even estimated, from these data.

TABLE 2
Numbers of longliners greater than 24 metres in LOA licensed to fish in the Indian, Atlantic and Pacific Oceans (as of September 2003)

Country

Small-scale vessels (between 24 and 35 m LOA)

Large-scale vessels (over 35 m LOA)

Indian

Atlantic

Pacific

Duplicate

Total

Indian

Atlantic

Pacific

Duplicate

Total

Australia

14

-

-

-

14

14

-

2

-

16

Belize

-

-

-

-

-

-

1

20

2

19

Bolivia

-

-

-

-

-

1

-

-

-

1

Brazil

-

11

-

-

11

-

-

-

-

-

Cambodia

-

-

-

-

-

-

-

3

-

3

Canada

-

5

-

-

5

-

-

-

-

-

China

72

-

149

-

221

21

60

78

39

120

Cook Islands

-

-

2

-

2

-

-

-

-

-

France

3

-

14

-

17

-

-

-

-

-

Ireland

-

8

-

-

8

-

-

-

-

-

Portugal

-

32

-

-

32

12

12

-

6

18

Spain

75

351

73

142

357

57

43

54

80

74

Ecuador

-

-

6

-

6

-

-

20

-

20

Micronesia

-

-

4

-

4

-

-

-

-

-

Fiji

-

-

37

-

37

-

-

-

-

-

Georgia

-

-

-

-

-

-

-

1

-

1

Honduras

-

-

-

-

-

-

4

-

-

4

Iceland

-

-

-

-

-

-

1

-

-

1

Indonesia

722

1

-

1

722

17

-

1

-

18

Iran

-

-

-

-

-

1

-

-

-

1

Japan

83

35

171

94

195

477

482

480

951

488

Republic of Korea

-

-

-

-

-

175

1

176

163

189

Madagascar

1

-

-

-

1

-

-

-

-

-

Mexico

-

-

6

-

6

-

-

3

-

3

Namibia

-

-

-

-

-

-

1

-

-

1

New Caledonia

-

-

3

-

3

-

-

-

-


Panama

-

10

38

1

47

-

2

15

-

17

Peru

-

-

-

-

-

-

-

1

-

1

Philippines

-

-

-

-

-

39

8

2

9

40

Seychelles

9

2

4

1

14

-

-

-

-

-

South Africa

-

7

-

-

7

-

10

-

-

10

St. Vincent

-

5

-

-

5

-

3

-

-

3

Taiwan Province of China

-

-

14

3

11

173

163

164

50

450

Thailand

-

-

-

-

-

2

-

-

-

2

USA

-

162

28

2

188

-

18

-

-

18

Uruguay

-

1

-

-

1

-

6

-

-

6

Vanuatu

-

1

-

-

1

-

-

48

-

48

Venezuela

-

13

-

-

13

-

18

-

-

18

Total

979

644

549

244

1 928

989

833

1 068

1 300

1 590

Swordfish Longline

75

483

87

142

503

69

69

54

86

106

Tuna Longline

904

161

462

102

1 425

920

764

1 014

1 214

1 484

"Duplicate" indicates the numbers of vessels counted more than once because they were licensed to fish in more than one ocean. Criteria for classifying small- and large-scale longliners are explained in Section 2.2.

Unfortunately, no governments other than that of Japan responded to questions regarding the numbers of vessels actively fishing in each ocean. Since the difference between numbers of vessels registered and the numbers actively fishing is important, logbook data for the Japanese fleet were analysed, using data on the names of the vessels and their registration numbers. The logbook coverage is nearly complete. The estimated total numbers of Japanese vessels that fished in each ocean are shown in Table 3.

TABLE 3
Numbers of Japanese longliners engaged in fishing in each ocean

Year

Coastal

Offshore

Government

Indian

Atlantic

Pacific

Total

Indian

Atlantic

Pacific

Total

Indian

Atlantic

Pacific

Total

1979

-

-

-


289

237

685

864

-

-

-

-

1980

1

-

553

554

310

284

696

897

17

-

36

42

1981

-

-

-

-

316

289

679

892

-

-

-

-

1982

-

-

-

-

287

255

571

861

-

-

-

-

1983

-

-

-

-

274

183

517

792

-

-

-

-

1984

-

-

-

-

291

213

467

748

-

-

-

-

1985

-

-

433

432

298

232

464

757

17

-

33

35

1986

-

-

-

-

267

187

509

757

-

-

-

-

1987

-

-

-

-

258

171

585

864

-

-

-

-

1988

-

-

-

-

219

194

518

739

-

-

-

-

1989

-

-

-

-

213

235

503

740

-

-

-

-

1990

-

-

332

332

193

238

535

745

12

-

37

49

1991

-

-

-

-

176

241

514

724

-

-

-

-

1992

-

-

-

-

160

238

442

653

-

-

-

-

1993

-

-

-

-

274

183

517

792

-

-

-

-

1994

-

-

-


204

195

409

788

-

-

-

-

1995

2

-

211

213

233

243

377

680

4

-

47

51

1996

-

-

-

-

240

279

309

651

-

-

-

-

1997

-

-

-

-

238

255

289

629

-

-

-

-

1998

-

-

-

-

227

240

290

578

-

-

-

-

1999

-

-

-

-

221

217

263

547

-

-

-

-

2000

-

-

139

139

189

203

236

495

3

-

41

44

2001

-

-

134

134

195

370

178

503

2

-

37

39


FIGURE 2
Total numbers of Japanese coastal, offshore and government tuna longliners that have fished anywhere in the world, by five-year intervals

The criterion for separation of coastal and offshore vessels is GRT (80 GRT during 1979-2001 and 120 GRT after that). Therefore the offshore category includes vessels that would have been classified as small-scale longliners during the processing of the positive lists. The government vessels are mostly training or research vessels, belonging to the central or local governments. These vessels were not included in the fishing capacity analysis, as their activities are not commercial fishing, even though they operate under the normal licensing system.

Since many vessels fish in more than one ocean, the sum of the number of vessels in the three oceans is far greater than the total fleet size. The total numbers of Japanese coastal, offshore and government tuna longliners that actively fished anywhere in the world are shown in Figure 2. The total numbers of Japanese offshore longliners that fished in any of the three oceans and the total numbers (eliminating the duplications between oceans) are shown in Figure 3. It is obvious that the numbers of active offshore longliners have been declining continuously. The numbers of the Japanese active offshore vessels for each ocean are compared with the total number of Japanese large-scale vessels estimated from the positive lists in Table 4.

TABLE 4
Comparison of Japanese large-scale tuna longliners in the positive lists and actively-fishing offshore longliners extracted from the logbooks (for 2001)

The total number of Japanese large-scale longliners from the positive list is 488, whereas the total number of such vessels obtained from the logbook data is 503. In addition, there are 39 government vessels (Table 3), so the total number of active Japanese longliners is 542. As explained in Section 3.2, the criteria adopted for defining large-scale longliners in this report is different from that used for defining offshore longliners in the logbook data, which accounts for most of the discrepancy.

It is obvious that not all the vessels that were licensed to fish in a given ocean actively fished in that ocean. This applies to other fleets, as well as that of Japan. Therefore, the analysis of the world-wide fishing capacity of any fleet cannot be achieved unless information on active fishing is available. It is regrettable that more information of this type was not available.

4. Estimates of the size of the fishing fleet

4.1 Estimates of the total number of large-scale longliners

Unfortunately, there is only fragmentary information with which to estimate the size of the large-scale longline fleet for past years. Also, it is clear that it is impossible, at least at present, to estimate the numbers of vessels actively fishing. Therefore, an estimate, as current as possible, was made for the entire world longline fleet, regardless of ocean.

In Table 5 the numbers of large-scale tuna longliners, estimated from the positive lists (Section 3.3), are compared with the estimates from the OPRT data (Section 2.5), for those countries for which data are available from both sources. For Japan, the number of active vessels estimated from the logbook is also included.

Most of the discrepancies are explained by the time lag between the two sources. The OPRT numbers are as of December 2003, while the positive list data are almost a year older. The positive lists were publicized on the RFMOs web sites in about August 2003, but the data had been submitted a few months prior to that by the respective governments (i.e. early 2003). Many activities took place during 2003. Many IUU vessels were re-registered to the Taiwan Province of China and to the Seychelles, which explains the discrepancies for those two countries.

Some minor discrepancies are due to real changes in fleet sizes during 2003 and to the misclassification of large-scale longliners. However, considering the quality of the original data, the similarity between data from two sources is encouraging.

In summary, analysis of the positive lists produced an estimate of 1 484 large-scale tuna longliners. Considering the fact that the OPRT data are more recent, and include vessels that were previously IUU vessels, and the fact that positive lists do not exist for western and central Pacific Ocean, it is likely that this is an underestimate. For this reason, this estimate (1 484) was modified, using the data from the OPRT for the fleets for which data are available (+101 vessels). In addition, there are currently about 30 IUU vessels. The addition of these produces an estimate of 1 615 for the total number of large-scale longliners in the world.

TABLE 5
Comparisons of estimates of the sizes of the fleets of large tuna longliners from different sources. The active Japanese vessels are those classified as licensed to fish offshore, and hence may include some small-scale vessels


OPRT report (end of 2003)

Positive lists (publicized in September 2003)

Active vessels (2001)

Japan

484

488

503

Taiwan Province of China

610

450

-

Republic of Korea

170

189

-

Philippines

17

40

-

Indonesia

14

18

-

China

105

120

-

Vanuatu

48

48

-

Seychelles

21

0

-

Ecuador

5

20

-

Others

0

111

-

Total

1 474

1 484

-

4.2 Current catch of large-scale longliners

The determination of the current fishing capacity of the large longliners requires information that is not available or difficult to quantify (e.g. vessel specifications, operational patterns, increases in gear efficiency and socio-economic factors). Also, there are other things that should be considered, such as the portion of time actually spent fishing for tunas. Under these circumstances, the fishing effort that may be derived from this fleet was considered in terms of tuna resources.

The problem is to define the resources (bigeye, yellowfin, albacore, and the three species of bluefin) available to the longliners and to the other types of gear. In this study, it was assumed that the shares of the stocks of these species among the fishing gears remain the same as in 2001-2002, and that the fishing patterns (i.e. age-specific fishing mortality by various gears) also remain the same.

According to the stock assessments carried out by the various RFMOs, almost all tuna stocks in the three oceans are at or below levels corresponding to the maximum sustainable yields (MSYs) (i.e. either the fishing effort is about equal to or greater than that corresponding to the MSY or the spawning biomass is about equal to or below the level corresponding to the MSY) (de Leiva and Majkowski, this collection). Many of these stocks are regulated, or there have been recommendations "not to increase the fishing mortality" for them.

Therefore, comparison of the fleet size with the catch by that fleet should be of interest. Miyake, Miyabe and Nakano, (2004) estimated the longline catches of the species mentioned above by species, area and country. However, the catches by longline cannot be classified by vessel categories.

In this report, these catches were separated into those made by large-scale longliners, small-scale longliners and by swordfish longliners (as bycatches), using the author's knowledge of the longline fisheries. However, the catches by small-scale longliners are often reported as having been taken by unclassified gears (artisanal). Because the numbers of small-scale longline fleet are unknown, it was difficult to determine whether the catches were made by longliners or some other gear, so the results should be considered as rough estimates.

The data indicate that during 2001 approximately 390 000 tonnes of tunas were caught by large-scale longliners, and 200 000 tonnes were caught by other longliners (small-scale longliners and/or longliners targeting swordfish). As the sashimi market consumes about 600 000 tonnes per year, this estimate appears to be realistic.

5. Conclusions

The longline fleet size, by large- and small-scale longliners is compared with the estimated tuna catches, by small and large-scale longliners, in Table 6. The data are segregated by ocean, but only the totals are of interest, as many of the longliners operate in more than one ocean during the same year. It should be noted that the catch corresponds to those made by small longliners while numbers of "small-scale" longliners refer to those included in the positive list, thus being greater than 24 metres in LOA. Therefore, the catches per vessel are not calculated for that category.

It should be noted that no data for small-scale longliners (vessels with LOAs less than 24 metres) are included in the table. Only the data for large-scale longliners are considered below.

The last row contains the best estimate for total number of large-scale longliners. The annual average catch of the registered vessels was 241 tonnes in 2002. The catch discussed here does not include bycatches of tunas by swordfish longliners nor bycatches of billfishes by longliners targeting tunas. Therefore, the catches of the marketable species would be somewhat greater than 389 251 tonnes. On the other hand, as explained in Section 5.1, the fleet size may be underestimated, in which case the catch per vessel could be less than 240 tonnes.

It is unlikely that all of the large-scale longliners are currently fishing at their full capacities, due to economic, social and management restrictions. If all these restrictions are removed, their potential catches, even at the current levels of abundance of the resources, would be greater than 240 tonnes per vessel.

However, if the fishing patterns, in terms of gear share, age composition and species composition, were to stay the same, any increases in the size of the longline fleet would not increase the catches much above the current levels because most of the stocks are currently harvested near or beyond the MSY levels. On the other hand, the same levels of catches can most likely be achieved with a smaller fleet size. In fact, if the sizes of the fleets that utilize the other gear types (purse-seine, pole-and-line, troll and small-scale longliners) were reduced by the same proportion as the large-scale longline fleet, the large-scale longline fleet would probably increase its share of the catch.

The market price of fish varies considerably by species and area and/or season of capture. The species composition of the catch is important, as the catch rates of lower-priced fish (e.g. yellowfin) are greater than those of the higher-priced fish (e.g. the three species of bluefin). Therefore, the boat owners can decide whether to direct their efforts toward lower- or higher-priced fish (taking into account the constantly fluctuating prices of the fish). In addition, the operating costs vary among fleets, distances from port, etc., so it is difficult to determine, on an economic basis, the most appropriate size for the longline fleet. In spite of the above, the current break-even point appears to be around 250 tonnes, regardless of the fleets. Each vessel tries hard to make a profit, changing the target species and areas of operation in accordance with the captain's judgment.

TABLE 6
Estimated fleet size and catches for small- and large-scale longliners, by ocean. The difference between the total and grand total for the large-scale longliners is explained in the text

Type of vessel

Ocean

Number of vessels

Estimated catch (tonnes)

Catch per vessel (tonnes)

Small-scale vessels (incomplete)

Indian

914

54 683

-

Atlantic

151

29 260

-

Pacific

458

112 244

-

Duplicate

102

-

-

Total

1 421

196177

-

Large-scale vessels

Indian

920

90 620

98.5

Atlantic

764

108 028

141.4

Pacific

1 014

190 603

188.0

Duplicate

1 214

-

-

Total (positive list)

1 484

389 251

262.3

Grand total (adjusted by other information)

1 615

389 251

241.0

The tuna resources that are available to large-scale longliners are also variable, since it is not a single-gear fishery. Some of the factors, other than natural fluctuations, that affect the available stocks are:

This study is preliminary. The results would have been much better if the data had been better. Each country should collect information on the names or registration numbers and the characteristics of each vessel registered in that country, including information on transfers of registration. Logbook data for every vessel should be collected and provided to scientists of the countries in which the vessels are registered or to scientists of the RFMOs, so that they can determine the catches, the oceans in which fishing was taking place, and the species toward which the vessels were directing their effort. Also the past trends in fleet size should be studied to analyse the relationships between fleet fishing capacity and abundance of the various stocks. Data on effort directed at swordfish and the catches of tunas made by swordfish longliners and of billfishes made by tuna longliners were not incorporated into this study, but they should be included in future analyses.

References

de Leiva, J. I. & Majkowski, J. 2005. Status of the tuna stocks of the world. This collection.

Farwell, C. J. 2001. Tunas in captivity. In B. A. Block & D. Stevens, eds. Tuna: physiology, ecology, and evolution: 391-412. Academic Press, San Diego.

Gillett, R. 2005. Global study of non-industrial tuna fisheries. This collection.

Miyake, P. 2005. A brief history of the tuna fisheries of the world. This collection.

Miyake, P. M., Miyabe, N. & Nakano, H. 2004. Historical trends of tuna catches in the world. FAO Fisheries Technical Paper. No. 467. Rome.


[30] During the meeting of the Technical Advisory Committee (TAC) it was recommended that the fleet be classified into the following categories: small - uncovered; medium - covered, but with no freezing capacity; and large - covered, and with freezing capacity. The "small" category in this report includes some vessels that would be classified as small and some that would be classified as medium in the new TAC classification. However, there are many factors to be considered in the classification of vessels, so, due to the complexity of the matter, the two categories, "small" and large, are retained in this report. The readers of this report should understand that "small" in this report consists mostly of vessels that are "medium", but also some that are "small", according to the TAC definitions.

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