Note sur l'étude d'évaluation de l'impact des pêcheries sur les populations de pétrels à menton blanc Procellaria aequinoctialis et de pétrels gris Procellaria cinerea aux îles Crozet et Kerguelen

This study reviews the impact of longline fishing on populations of white-chinned petrels and grey petrels from 2004 to 2006 at Crozet and Kerguelen (58.6 and 58.5.1 respectively).
It shows that the population of white-chinned petrels at Possession Island (Crozet) decreased sharply between 1983 and 2004, with the main cause being changes in environmental variables. Nevertheless, the decrease in the population was more marked as a result of previous levels of incidental mortality. At present, the level of mortality of white-chinned petrels in Subarea 58.6 has not reached the critical point beyond which the population would be at risk of declining.
Past levels (up to 2003) of incidental mortality of white-chinned petrels in Division 58.5.1 have probably had a negative effect on the population. At present, incidental mortality of this petrel has a limited effect on the population.
The population of grey petrels in the Kerguelen archipelago (Division 58.5.1) is also very sensitive to changes in environmental variables and particularly to positive values of the Southern Oscillation Index (SOI). The legal toothfish fishery had a significant negative impact on adult survival and population growth rate between 2001 and 2004. Since 2005, incidental mortality of this species is no longer at the levels above which the number of birds killed could cause a decline in the population. In order to limit the decrease, new conservation measures were established for the 2006/07 fishing season.