CCAMLR

This paper summarises the incidence of entanglements and incidental mortality of birds and seals reported by CCAMLR Members for the CCAMLR Convention Area and adjacent waters from 1985 onwards. A bibliography on entanglement, incidental mortality and effects of marine debris on seabirds and marine mammals is attached. The bibliography includes references taken from papers submitted to CCAMLR.

In recent years, a new longline fishery for the fish Dissostichus eleginoides has developped in the vicinity of South Georgia and Kerguelen islands, two internationally important breeding areas for procellariiform birds. Attractiveness of this fishery for seabirds, together with the incidental capture of birds and a method to reduce mortality were investigated during 13 days of fishing activity in Kerguelen waters in February 1994. Between 100 and 600 seabirds were always observed behind the longline vessel. The main ship-following species were the white-chinned petrel (67% of the counts), the giant petrels (8%) and three species of albatrosses, the wandering (11%), black-browed (6%) and grey-headed (2%) albatrosses. All these species are attracted by sinking hooked baits during line settings, more attempts to feed on baits being made by skilled divers such as the white-chinned petrel (87% of the total number of tries), the black-browed (7%) and the grey-headed (6%) albatrosses, than by species never observed submerged such as the wandering albatross (

Studies carried out over the past three decades in the French austral territories indicate that most albatross and giant petrel populations have markedly declined. Demographic studies indicate that these declines are mainly the result of increased adult mortality. This high rate of mortality has been suspected to be the result of mortality incurred in long-line fisheries. Satellite tracking studies of breeding birds and band recoveries of non breeding birds indicate that during and outside the breeding season these populations are in contact with long-line fisheries, mainly the pelagic Japanese tuna fishery and in a lesser extent the neritic Dissostichus fishery operating in the Kerguelen EEZ. The decrease in the fishing effort of the Japanese fishery during the recent years has probably resulted in the slow recovery of great albatross population. Long-line fisheries are likely to represent a major threat for long-lived seabirds in the southern ocean, especially the tuna fishery for the Indian Ocean populations. Potential threats from the Kerguelen Dissostichus fishery exist but can be minor if measures to reduce mortality continue to be enforced in the EEZ.

Incidental captures of seabirds, and the behaviour of seabirds around the fishing gear as it was deployed, were observed during 8-days' fishing of a New Zealand-owned tuna long-liner. From 11,200 hooks set 6 seabirds were hooked and recovered: 5 Wandering Albatross Diomedea exulans of which 3 were released alive, and one Black-browed Mollymawk D. melanophrys impavida. Relatively more birds survived hooking in this study because of the lighter gear and quicker recovery of the long-line (about 6 hours between beginning the set and beginning hauling-in).
Petrels, particularly Cape Pigeons Daption capense, were mainly responsible for bringing the sinking baits back to the surface where albatrosses/mollymawks subsequently ate most of them. About 1.2% of baits were taken by seabirds, but only 4.5% of bait-takes resulted in a bird being hooked. The mollymawk was hooked at night near full moon, but under thick cloud.
Most bait-takes occurred in daylight, particularly before dusk. The vessel's bird-scaring line seemed to reduce, but not eliminate bait-taking. The mortality rate of seabirds (0.2711000 hooks set) is similar to that in the only other two reported studies.
Seabirds scavenged intensively on the waste baits (41% of those cast) thrown overboard during hauling-in. More birds followed in the wake during hauling than during setting.

Although longlining is regarded as a highly conservation oriented method of fishing, bycatch of seabirds on longlines is a problem in certain seasons and areas. Birds feeding on the bait during setting of the gear might cause considerable bait loss and occasional hooking of birds might eventually give high mortalities considering the large amounts of hooks used. Both from a fishery and bird conservation point of view there is a strong incentive to solve this problem. This paper describes trials with a seabird scarer in the Norwegian longline fishery. The scarer, a line with streamers trailing behind the vessel during setting of the gear, proved to be an effective device for scaring the birds away, and gave significantly reduced bait loss and no bird mortality.

An age-structured model of a wandering albatross Diomedea exulans population is developed to simulate population trends over time, using demographic parameters from the population at Possession Island Crozets, during 1968 to 1986. The simulation results portray a population decreasing at a rate of 2.29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5-10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30-50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trend; short-term (

The estimated breeding population of wandering albatrosses on Macquarie Island increased from 17 in 1956 to a maximum of 97 in 1966, and then declined at an average rate of 8.1% per year. Mark-recapture analysis shows that the population is not closed (i.e., subject to immigration and emigration). The decline is correlated with the onset of large-scale fishing for tuna in the southern hemisphere using longlines. The effect of longline mortality on the population dynamics of the wandering albatross is estimated. An annual number of longline hooks in the southern hemisphere tuna fishery of 41.6 million is calculated as the ceiling below which the population would begin to recover.

A conservative calculation of the number of albatrosses killed annually on Japanese longlines in southern oceans in 44 000. The actual figure could be double and is sufficiently high to substantiate claims that serious declines in albatross populations are due to this fishing activity. Albatrosses have an economic impact 0n longline fisheries with annual losses to the southern bluefin tuna fishery alone exceeding $A 7 million. If all fish species and the total longlining effort were considered, it would be many millions of dollars greater. Apart from a concern for albatrosses, Japan's longline fishermen would also benefit by using the solutions offered. It is suggested that a 70% reduction ill the problem is possible and that an overall reduction in excess of 90% could be achieved. Further monitoring is essential.