DRIFTNET DATA COLLECTION PROGRAMS
1952-1990


The North Pacific Salmon Driftnet Fishery

In 1952, Japan initiated a salmon drift gillnet fishery using large scale monofilament nylon driftnets. One year later, in 1953, the International North Pacific Fisheries Commission (INPFC) was established under the International Convention for the High Seas Fisheries of the North Pacific Ocean (North Pacific Convention) to attempt to regulate this fishery and to ensure the protection of North American salmon stocks.

Between 1962 and 1971, Japanese Fisheries Agency (JFA) research vessels collected data on the North Pacific salmon mothership driftnet fishery. Observers recorded both catch and by-catch data. They reported 0.37-0.65 cetaceans were caught per 1000 tans, with a maximum of 1.42 per 1000. Between 1977 and 1987, the JFA research vessels collected catch and by-catch data on the Japanese salmon land-based fishery. They recorded 2,204 seabirds belonging to 16 species killed in 413 net sets. Based on historic fishing effort and estimated catch rates, Japanese and United States researchers estimated that more than eight million seabirds were killed by only the large-vessel component of the land-based fishery since 1952 (DeGange and Day 1991). The United States also collected salmon driftnet fishery data during the 1960s. Their data indicated an average of 6.66 cetaceans caught per 1000 tans (approximately the amount of driftnet set by one squid vessel each night). United States observers were first placed on board commercial Japanese salmon motherships and catcherboats in 1980. In addition, each year since 1978 Japan has reported to INPFC the total catch and by-catch taken by both its mothership and land-based salmon driftnet fisheries.

Data on the North Pacific salmon fishery was also collected by Canada and the United States. In 1987 and 1988, Canada conducted two salmon research cruises on board the W.E. Ricker. The 1987 cruise took place in an area where few, if any, salmon were expected to be found (38 - 45 deg N, 150 - 180 deg W) in 12 deg C water. All six species of salmon were caught (LeBrasseur et al 1987). The cruise data also indicated that between 100 and 300 million pomfret may have been discarded annually as unwanted by-catch. The 1988 cruise, again conducted in the squid fishing area (38 - 46 deg N, at 151 deg W and 155 deg W), caught both salmon and squid, indicating that the segregation between the two species was not distinct (LeBrasseur et al 1988). The cruise also observed 10 commercial vessels fishing north of where their national regulations said they should be.

In 1980, a U.S research catcherboat monitored ten gillnet operations. An average of 2.6 per set Dall's porpoise drowned in the nets. In 1980, 1981, and 1982, U.S. observers were placed on board the Japanese mothership fleet and monitored both motherships and catcherboats. The take of Dall's porpoise ranged between 0.13 and 0.96 per set (Jones 1984; Odate 1984).

South Pacific Large-Mesh Driftnet Fisheries

Data Collection by Australia and New Zealand

Between 1981 and 1983, Australia monitored 157 sets by the large-mesh Taiwanese fleet fishing in the Arafura and Timor seas (Harwood and Hembree 1987). Based on the data collected, researchers estimated that on average each driftnet vessel caught 1.8 sunfish, 2.2 sharks, 1.8 billfish, 11.1 Ray's Bream, and 3.6 dolphins each night the vessel fished. The observed cetacean catch totaled 4,463 and a significant decline in the cetacean catch rate against the cumulative fishing effort was recorded during the study period. The main species taken were the bottlenose dolphin, the spinner dolphin, the spotted dolphin and the false killer whale. Australia brought the fishery to an end in 1986. In 1989, Australia totally banned driftnet fishing from its EEZ. New Zealand observers also monitored large-mesh driftnet vessels in the Tasman Sea and the South Pacific convergence zone (SPCZ) in 1987 and 1989. Data collected by a New Zealander on board a Japanese fisheries research agency (JAMARC) large-mesh driftnet vessel operating in the Tasman Sea indicated a catch rate of 2.1 per 36 km set of the common dolphin and 0.5 per set of the relatively rare striped dolphin. Albacore dropout rates averaged 8.9%. The data gathered from these monitoring programs convinced New Zealand to ban driftnet fishing from its EEZ in 1989 and to sign the Wellington Convention banning it from a large portion of the South Pacific. In 1990, private environmental consultants from New Zealand conducted both surface and underwater photographic observations to document the by-catch. Quantitative data was collected for 126 km of driftnet set by the commercial fleets fishing between 37 deg 40 min - 41 deg 42 min S and 156 deg 26 min - 161 deg 03 min E (Coffey and Grace 1990).

Data Collected by Japan

Beginning in 1982, JAMARC began a series of 11 or more development surveys to assess the commercial potential for driftnet fishing in the South Pacific. The target species comprised less that 50% of the retained catch (SPF 1991). Discards and dropout rates were not recorded. In 1989, the Japanese conducted a research cruise in the Tasman Sea. A total of 712 km of net were monitored. By-catch included skipjack tuna, yellowfin, bigeye tuna, slender tuna (132 per 1000 km), swordfish, striped marlin, blue marlin, shortbill spearfish, flying squid (138 per 1000 km), blue shark, mako shark (93 per 1000 km), hammerhead and pomfrets. Also caught were fifty common dolphins, ten striped dolphins, one pilot whale and one or two southern bottlenose whales, three leatherback turtles, and two unidentified birds. In 1989-1990, Japan conducted a resource survey for new fishing grounds in the South Pacific Ocean. Common dolphin and striped dolphins accounted for 78% and 14% of the total cetacean by-catch. A southern bottlenose whale, still alive, was cut loose with net still wrapped around it (Watanabe 1990).

Catch Data from a Virgin Waters Driftnet Fishery Experiment

In 1989, the Federated States of Micronesia (FSM) and Japan conducted a trial joint venture in the EEZ of the FSM, in an area never before fished by driftnets (Goldblatt 1989). An FSM observer was on board a 30 meter driftnet fishing boat, the Monju Maru, during 30 days of driftnet fishing. Each evening the boat set seven to eight nets, each approximately 3.2 km long, 7.6 m deep, with a 76 mm mesh. The nets were retrieved in the early morning.

The observer reported that fish caught in the nets tended to died quickly, but it was 7-14 hours before the dead fish were hauled on board, processed and frozen. The captain called the fish "dogfood". The majority of the yellowfin tuna caught were juveniles, weighing about 15 pounds. Yellowfin tuna can grow to over 100 pounds in their first year of life. Sixteen percent of the catch were discarded because they were not marketable, spoiled, or had been bitten by sharks. The by-catch included 356 sharks, which were discarded after their fins were cut off.

More than one third of the by-catch were classified as protected or endangered species, including leatherback, green and hawksbill turtles, and eleven whales, nine of which were caught in one set. The turtles were kept, except for two leatherbacks that were discarded after being gaffed. Almost a hundred dolphins were brought on board, one for every nine tuna caught, as well as several dolphin tails. The rest of these dolphins had been eaten by sharks as they hung in the net. Those dolphins still alive had their tails cut off to facilitate removal from the net, after which they were thrown overboard. At one time the boat's propeller became entangled in the net. A large section of the net was cut away and discarded at sea leaving it to ghost fish on its own.

The observer recommended no further driftnet fishing in the Federated States of Micronesia. The reasons: low catch rate, poor quality of fish, large amounts of discarded marine life, and the killing of protected and endangered animals. The observer recommended alternative fishing methods, such as longlining, as likely to be more profitable, yield a higher quality of fish and cause much less destruction to the FSM's marine resources. As a result of this study, the Federated States of Micronesia banned driftnet fishing from their EEZ.

The North Pacific Large-Mesh Driftnet Fisheries

In 1982 and 1983, JAMARC carried out 51 driftnet operations for a Pacific pomfret resource survey. Nine species of cetaceans were caught as by-catch. Striped dolphin, northern right whale dolphin and common dolphin comprised 37%, 29% and 21% of the total catch, respectively (Watanabe 1990). In 1989, the Fisheries Agency of Japan conducted a large-mesh survey cruise in the North Pacific. A pair of mother and offspring pygmy sperm whales and a Pacific white-sided dolphin were killed.

The North Pacific Squid Driftnet Fishery

Single Nation Research Cruises

Data is available from research cruises conducted by Japan in 1982, 1983, 1985, 1986, and 1987 (Murata et al 1988). By-catch of marine mammals and birds were recorded. The catch commonly included Dall's porpoise, northern right whale dolphin, pacific white-sided dolphin, and an assortment of other dolphins, seals, whales and birds (Murata 1986; Takagi 1983). In 1986, the Taiwanese conducted a research cruise using both monofilament and multifilament nets. An average of 1.6 marine mammals were caught per set. In 1990, the ROK conducted experimental squid fishing operations, testing 72 mm, 86 mm and 96 mm meshes (Gong et al 1991). Between 1979 and 1987, Canada conducted a number of cruises to assess the distribution, abundance, and fishery potential of flying squid within 450 km of its coasts (Welch, Margolis, and Henderson 1991). By-catch included salmonids, marine mammals, and seabirds. Between 1986 and 1990, Canada began a series of annual cruises with the research vessel W. E. Ricker to determine the high seas distribution of salmon and squid. In 1988, the Canadians conducted a research cruise in the North Pacific commercial squid fishing area using standard mesh and trammel mesh (Herczeg 1988). By-catch included five species of salmonids, blue shark, pomfret, seabirds and marine mammals.

Joint Research Cruises

In 1983, 1985 and 1986, experimental squid driftnet fishing was conducted by Japanese and Canadian vessels in the eastern Pacific Ocean. Pomfret and blue shark were the major by-catch species. A total of 50 mammals were caught by three vessels fishing in 1986 (Sloan 1984; Jamieson and Heritage 1987).

During 1986 United States scientists participated in two squid driftnet research surveys with the ROK (Park et al 1987; Clausen 1986; Day 1986) and Taiwan (Sigler 1986; Dahlberg 1986) and one squid/salmonid cruise with Canada (Bernard 1986). In 1987, United States scientists participated in four squid cruises, one each with the ROK (Gong et al 1989; Seger 1987) and Taiwan (Kazama 1987; TFRI 1987), two with Japan (Johnson 1987; Risner 1988) and one squid/salmonid cruise with Canada (Muto 1987). In 1988, U.S. scientists participated in two squid surveys with Taiwan (Fitzgerald 1988) and the ROK (Rowlett 1989; Gong et al 1988). In 1989, a U.S scientist participated in a squid survey with the ROK (Gong et al 1990).

Observers on Commercial Driftnet Vessels

Japan and the United States began placing observers on board Japanese commercial squid drift net vessels in 1982 (Tsunoda 1989; Cary and Burgner 1983). The data indicates that in the early 1980s the Japanese squid fishery averaged 1.7 cetaceans killed per 1000 tans fished, the average amount of driftnet a single vessel sets each night of the fishing season. Japan reported 2,232 Dall's porpoises incidentally taken by the squid fishery in 1986 (INPFC 1988, Doc 3270). United States observers were permitted to observe commercial squid driftnet operations on board a Korean vessel in 1988 (Gooder 1989). A few additional observations have been made by observers from the vantage point of Coast Guard cutters (Ignell, Bailey, and Joyce 1986) and private vessels. In the early 1980s, Japan also regularly reported data from its squid and large mesh driftnet fisheries to INPFC. The ROK began collecting and analyzing data from its high seas squid driftnet fleet in 1981 (Kim et al 1988; Gong et al 1985, Gong 1985).

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