RT19: Death by drowning: A global review of bird bycatch by longline fisheries

BirdLife International Seabird Conservation Programme, Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa, fax 27 21 650 3846, e-mail jcooper@botzoo,uct.ac.za

Cooper, J. & Wanless, R.M. 1999. Death by drowning: A global review of bird bycatch by longline fisheries. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban: 3195-3197. Johannesburg: BirdLife South Africa.

The session began with a brief introduction summarising the issue and extent of seabird mortality caused by longline fisheries and the international activities being undertaken to reduce mortality. Especially active in this field are the Food and Agriculture Organisation of the United Nations and work falling under the auspices of the Bonn Convention on the Conservation of Migratory Species of Wild Animals. Three speakers then gave short addresses, summarised below, to set the scene for the ensuing discussion.

Despite concerted efforts by the navies or coast guards of various nations, illegal and unregulated longline fisheries, particularly in the Southern Ocean for the Patagonian Toothfish Dissostichus eleginoides, continue to represent a major threat to seabirds. France has recently increased the fine for vessels caught fishing illegally as the deterrent effect of original penalties appeared to be minimal. This resulted in non-payment of penalties and the impounding of vessels, catch and equipment by the French government.

In the 1996/97 season, 45 illegal longline vessels, representing a number of countries, including European Union and South American nations, were known to be fishing around the French sub-Antarctic Iles Crozet. In the 1997/98 season, seven and 25 illegal longliners were believed to be fishing around Iles Crozet and Kerguelen, respectively. The populations of toothfish around islands where poachers have concentrated their efforts appear to have been rapidly depleted.

The regulated fishery, comprising both French and Ukrainian vessels, hooked a total of 953 birds, of which 92% were White-chinned Petrels Procellaria aequinoctialis. There was an average catch-rate of 1.53 birds per 1000 hooks, but this is extremely variable, probably due to seasonal effects and the quality and frequency of the employment of mitigation measures. This is known to be a source of variable bycatch in other toothfish fisheries. By extrapolating these estimates to estimates of total fishing effort, around 20000 White-chinned Petrels are caught in this fishery annually, with a further 45000 killed in the unregulated fishery (for which estimates must be viewed as conservative, since poachers are unlikely voluntarily to employ mitigation measures). Ukrainian vessels reported that bird-scaring lines did not reduce bycatch. The construction and correct deployment of such lines are considered critical in determining their efficacy.

New Zealand has an official, funded observer programme for its domestic longline fleet. Various mitigation measures are in force and experimental underwater-setting devices are currently being tested. Albatross populations are being modelled and individuals satellite-tracked to determine the extent to which they are susceptible to longline fishing during different stages of their life-cycle and breeding seasons. Anecdotal evidence from some trawl fisheries suggest that birds are able to establish which vessels do not discard fish and offal and appear to learn to avoid these vessels. Contrary observations were reported from trawl fisheries in Australian waters.

Although national legislation and policing is essential to protect birds and ensure sustainable fishing practices, many pelagic seabird species are wide-ranging, especially outside of their breeding season. It thus befalls international bodies or multilateral agreements to ensure co-operative efforts to protect these species.

Norway has conducted initial tests on the effectiveness of the Mustad underwater setting device. The hydraulic tube can set up to a maximum depth of 1.75 m below the surface. It is theoretically possible to set considerably deeper than this. The cost of creating prototypes has thus far made developing such a device unfeasible, especially given the lack of demand for the device currently under investigation.

The system is less effective in heavy swell and may be barely effective at all. Results of the trials revealed a higher bycatch of birds (95% Northern Fulmars Fulmarus glacialis) when the underwater tube was used. More birds, however, were hooked in the wings and legs than were hooked in the bill. The latest version did not appear to have any impact on the catch-rates of target species.

Discussion was then led on the subject of the availability of new mortality information, and on the development of mitigation measures. Very little data are available from South American longline fisheries, especially those bordering the Pacific Ocean. Argentina, Chile, Ecuador and Peru have longline fisheries known or thought to result in seabird mortalities, but quantitative data are lacking. Tropical tuna longline fisheries are almost completely data deficient, despite the existence of several active observer programmes. Observers are not required to report any seabird interactions/deaths and therefore nothing is known about the extent of any interactions. Anecdotal evidence suggests that frigate birds (Fregatidae) are attracted to troll lures and that boobies (Sula) are occasionally caught on artisanal longline hooks. However, the small artisanal vessels are likely to attract few birds and thus are thought to pose less of a threat.

Other non-fish bycatch species, such as sharks, turtles and small cetaceans, should be considered in reviewing seabird bycatch-mitigation measures, especially as these may be in conflict with one another. There is a need to link current efforts and involve other role-players.

Weaning birds from vessels, by means of various discard-management procedures, is possibly a long-term solution. In addition, this may be important in areas where greater catch-utilisation/retention becomes widespread. The importance of engaging fishers in efforts to reduce bycatch, to ensure their co-operation and active involvement was stressed. Further to suggestions made at the Albatross Conference held in Hobart, Australia in 1995, a task-force should be established to assist/train/educate fishers in bycatch avoidance. A scheme that rewards good companies/fishers and that enforces the re-training of fishermen that do not perform well, merits further investigation. In this regard the ‘eco-labelling’ activities of the Marine Stewardship Council can play an important role. The use of artificial baits which could be made distasteful to birds is under investigation in Australia and Norway. Night setting may be effective for most species, but White-chinned Petrels remain unaffected by this measure as they are proficient nocturnal foragers. The use of a sound-cannon to scare birds has been tested, but appeared to lose efficacy fairly quickly. The occasional firing of a projectile may serve to keep birds scared of the loud bangs of a sound-cannon. The use of distress calls, or olfactory irritants released during setting, may deter birds.

After discussion, the RTD attendees approved the following text:

‘We, marine ornithologists of many nations attending the 22nd International Ornithological Congress in Durban, South Africa in August 1998, have taken note of the serious levels of mortality of seabirds continuing to be caused by longline fisheries in many parts of the World. We are especially concerned by the population decreases occurring among albatrosses and petrels in the Southern Ocean caused by longline mortality, including from unsustainable, illegal and unregulated fishing. We further note that these decreases have resulted in most albatrosses being placed on the World Conservation Union (IUCN) Red List of threatened species. We view the recovery of affected seabird populations as a necessary test of the sustainability of those longline fisheries that cause the mortality of seabirds.

We have also taken note of and commend international activities being undertaken to reduce such seabird mortality by BirdLife International, the Bonn Convention on the Conservation of Migratory Species of Wild Animals, the Commission for the Conservation of Antarctic Marine Living Resources, the Commission for the Conservation of Southern Bluefin Tuna, the Food and Agriculture Organisation of the United Nations, the Scientific Committee on Antarctic Research, the Valdivia Group of Temperate Southern Hemisphere Countries for the Environment and the World Conservation Union; as well as national activities within a number of countries, including but not limited to Australia, France, Japan, New Zealand, Norway, South Africa, the United Kingdom and the United States of America.

We dedicate ourselves to continue to monitor and actively to support the above activities, as well as encourage and support further necessary initiatives, so that seabirds continue to fly the World's oceans’.