Net loss: Fishing link to death march
The sudden disappearance of many critically endangered penguins from a predator-free island may be connected to fishing nets, researchers say.
The endangered hoiho (yellow eyed penguin) has a population on Whenua Hou, also known as Codfish Island, in Foveaux Strait, which separates the South Island mainland from Stewart Island/ Rakiura.
The native species is the world’s most endangered penguin. It features on the $5 note and is frequently used in New Zealand’s branding, but research shows it will likely be extinct on the mainland within two to four decades.
Researchers who last month returned from the remote island said areas once filled with penguins were empty, and birds that used to be in pairs were alone.
The cause was not immediately clear, but one researcher said set-nets from local fishermen may be responsible. The penguins foraged in the same area, and at the same depth, as the fish the nets were intended to catch.
Data from earlier this year suggested hundreds of penguins may be caught in set nets every year in events that go unreported.
The data showed 14 penguins were reported as killed last year. Almost all of them were found by Ministry for Primary Industries (MPI) observers, who inspected just 3 per cent of hauls. Fishers are legally required to report any penguin by-catches to MPI.
Dr Thomas Mattern, who has studied the hoiho for about 15 years, said the situation was dire.
‘‘On the mainland, they’ve been in a more or less constant decline since the late 1990s,’’ he said.
‘‘The way things are progressing right now, I fear that we’re marching towards extinction.’’
There had been examples of mass hoiho die-off before, but they were localised in Otago and due to an unidentified toxin, potentially related to agricultural run-off. It was unlikely to have caused the die-off at Whenua Hou.
It is understood multiple researchers have raised setnetting as a likely factor.
‘‘Whatever ends up in nets is either not reported or not happening. I tend to think it’s the former,’’ Mattern said.
‘‘I think set-netting is certainly a problem, but I think it’s an issue of careless individual fishers rather than the industry as a whole.
‘‘All it takes is one wrongly set net and you can end up with heaps of penguins in one go. If you have a population of only 200 breeding pairs left on the mainland . . . if you take out 10 birds at once that might have the effect we observed further south.’’
He wanted the issue selfregulated by the fishing industry, as the issues involved were ‘‘highly political’’ and could constrain the Government from quick action.
‘‘There’s a lot of talking involved, and I personally don’t think we have the time. I fear that if anything is going to be decided it will be too late.’’
Advocacy group Forest & Bird has raised the issue.
Chief executive Kevin Hague said the reported die-off was concerning. Urgent action was needed from various groups, including the Government, to save the hoiho.
‘‘It’s consistent with what’s been observed in other nesting sites we’re heavily involved in,’’ he said.
‘‘It’s indicative of a pattern of steep decline, which – given this is the world’s rarest penguin – is very, very worrying.’’
Set-net fisheries were one of several ‘‘poorly managed risks’’ to penguins, but more evidence was needed to confirm what caused this particular die-off.
Given researchers pointed to the fishing link, Hague said it was crucial MPI rolled out its plans to put cameras on all boats to monitor their hauls.
‘‘Having the actual evidence, as opposed to just speculation about what may be behind this precipitous decline in the species, is essential,’’ he said.
‘‘If we don’t have an urgency of action, it’s highly likely, I think, that we’ll lose this species.’’
The new Government has proposed to split up MPI, creating a new Fisheries department.
MPI did not return a request for comment before deadline.
We’re marching towards extinction. Dr Thomas Mattern