Black Petrel - Threats To The Survival of The Black Petrel

Threats To The Survival of The Black Petrel

While at sea:

• Black petrels are caught by commercial and recreational fishers both in New Zealand and overseas (Abrahams et al. 2010, Thompson 2010, Richards et al. 2011).
• Ministry of Fisheries research shows the black petrel is the most at risk seabird in NZ from commercial fishing, estimating that between 725 and 1524 birds may have been killed each year in the period 2003 to 2009 (Richards et al. 2011).
• Petrels may be drowned by taking long line hooks after they are set (launched) or when they are being pulled onto boats.
• Inshore snapper and bluenose bottom long line fisheries are the greatest risks, especially where fisheries overlap with foraging patterns of breeding birds (Richards et al. 2011).
• Reported deaths by fishers are low – since 1996, there have been only 38 birds reported caught and killed in NZ waters by local commercial fishers, mainly on domestic tuna long-line and on snapper fisheries (Richards et al. 2011, Thompson 2011, Bell et al. In Press A).
• Less than 0.5% of boats in these high risk fisheries had observers on board in any one year.
• The level of deaths in fisheries outside NZ waters is unknown.
• There are anecdotal capture reports from recreational fishers especially in the outer Hauraki Gulf (Abrahams, et al. 2010) where birds are commonly reported.

Threats in main breeding colony:

• On Great Barrier feral pigs are known to dig up burrows and eat eggs and chicks – in one example in 1996 pigs destroyed 8 burrows in one incident (Bell & Sim 1998).
• Feral cats can kill adults on the ground or at the nest as well as chicks
• Cat numbers on Great Barrier are impacted by trapping by the Department of Conservation in the Whangapoua basin but there has been no specific protection of the colony to date
• Kiore and ship rats are also present on Great Barrier but predation levels are between 1 and 6.5% per annum (Bell et al. 2011); kiore cannot eat through a black petrel egg
• Risk to black petrel survival from a one-off event/events is significant due to limited habitat for breeding / i.e. a single site on Hirakimata on Great Barrier Island (for example fire, storm damage or predator invasion at main colony).