Collecting dead birds from Bay of Plenty beaches after the Rena grounding showed that not all the deaths were caused by the 350 tonnes of heavy fuel oil that leaked from the vessel.
The team that handled more than 2000 oiled birds also found 64 unoiled flesh-footed shearwaters that were in good body condition, and found evidence that some had apparently been killed as a result of interactions with recreational fishers.
The flesh-footed shearwater is included on the IUCN Red List of Threatened Species.
“Of the 15 flesh-footed shearwaters autopsied, hooks used by amateur fishers (possibly for snapper) were found inside two birds, but most deaths were caused by trauma. This included broken wings, crushed skulls and stab wounds—presumably inflicted when birds were removed from fishing hooks after being pulled onboard,” says Alan Tennyson, Curator at Te Papa.
Alan worked with the Massey University veterinary team and Maritime New Zealand in the aftermath of the oil spill.
Other unoiled dead birds found were common diving petrels, sooty shearwaters, Buller’s shearwaters, little penguins and white-faced storm petrels. Although some had died before the spill, starvation appeared to be the main cause of death.
Edward Abraham of Dragonfly adds, “We have known that birds are caught by recreational fishers for a while. We haven’t had much evidence of the effect of being caught on the birds. This find shows that birds may be killed as a result of being hooked.”
In their report, based on interviews with fishers, Dragonfly estimated that in the northeastern region of New Zealand (which includes the Bay of Plenty and the Hauraki Gulf) there were somewhere between 6 000 and 16 000 seabird captures per year by recreational fishers. Although many of the birds may be unharmed, and simply unhooked or untangled and allowed to fly away, some proportion of these captured birds will be being killed.