Note sur l'étude des effets environnementaux, spatiaux, temporels et opérationnels sur la mortalité accidentelle des oiseaux dans la pêcherie à la palangre dans les secteurs de Crozet et Kerguelen en 2003–2006

Incidental mortality has diminished considerably in comparison with the period from 2001 to 2003 (Delord et al, 2004).
During the 2003/04, 2004/05 and 2005/06 fishing seasons the incidental mortality of seabirds was reduced by approximately half each year.
A multivariate analysis has revealed that the incidental catch of white-chinned petrels and grey petrels is caused by a complex set of variables relating to the environment and fishing techniques. Results suggest that a significant proportion of the mortality of white-chinned petrels and grey petrels can be explained by the effects of season and geographical area, as was the case for the period 2001-2003.
Incidental mortality varies according to geographical area, being higher at Kerguelen (where there are some geographical disparities, with higher mortality in the northern and central areas in the east, and northern and southern areas in the west) than at Crozet.
Analyses show that a proportion of the incidental mortality can be explained by other factors, such as, for example, the type of lines used (integrated-weight lines or otherwise, or a mixture of both). The number of streamer lines is also a factor which influences incidental mortality, the rate of which is lower when the number of streamer lines deployed behind the vessel is increased.
This study highlights the phenomenon of incidental capture of live birds during hauling, and of the larger number of species involved than is the case during setting.