Biased academia inflating fishing threat to sea lions
This year’s Auckland Island squid season has now closed, with no reported sea lion deaths.
The Ministry for Primary Industries summary released on July 1 shows there were 1364 tows in the SQU6T fishery, of which 92 percent were recorded by observers.
This was more than double the effort of the previous year when there were 616 tows, with an 88 percent observer coverage and just one recorded sea lion death.
In 2014 there were two mortalities from 761 tows, of which 643 (84 percent) were observed.
And in 2013 there were three deaths from 1015 tows with 86 percent observer coverage, the MPI reports show.
But instead of being lauded, the fishing industry is getting the usual caning from academic activists ignoring inconvenient truths.
Around the turn of this century, trawlers were estimated to be incidentally catching as many as 100 sea lions in a bad year. In the 22-year period between 1992 and 2013 there were 388 recorded sea lion captures in commercial squid trawl fisheries, with only about seven percent released alive.
The number has fallen dramatically, as the MPI figures show. That is due to individual vessel management plans, codes of best practice and the introduction of Sea Lion Exclusion Devices (SLEDs). The design, adapted from turtle exclusion devices used in the Australian prawn fishery, allows small species like squid to be trapped in the net whilst preventing sea lions from entering and allowing them to exit through an escape hole in the top of the trawl. All vessels in the squid fishery (SQU6T) deploy SLEDs. So, too, do those in the Campbell Island southern blue whiting fishery (SBW61).
“Modelling of actual captures suggests that 85 percent of sea lions exit a trawl net with a SLED,” according to the threat management plan prepared by MPI and the Department of Conservation. “Modelling of collisions with SLEDs suggests the risk of trauma or concussion is around three percent.”
The management plan, which is open for public comment, estimated sea lion pup production on the Auckland Islands was 1727 in 2016, up from a low of 1501 pups in 2009. The total species population estimate is 11,800.
There are four know breeding populations – the largest on the Auckland Islands in the Southern Ocean representing two thirds of the total. The other three are on Campbell Island, Stewart Island and the Otago coast.
The biggest threat to the species is disease, a highly virulent strain of the bacteria Klebsiella in particular, according to the sea lion study scientists.
“Disease outbreaks caused by bacterial infections are significant sources of mortality for sea lion pups, in particular the outbreak in 1998 (the year with the highest pup count on record) that killed at least 1600 pups (53 percent of pups born that season) and at least 74 adult females on the Auckland Islands,” the threat management plan said.
Another significant threat, one that could be prevented, is sea lion pups falling into deep holes on the breeding islands and either drowning or dying of starvation.
“In the 2015 season 696 pups were counted by researchers at Campbell Island. However there was a 58 percent pup mortality rate, two thirds of which was attributed to starvation and one third to trauma. Both these causes of death may be the end result of pups falling into holes.”
So how does what is a good news story on the impacts of fishing on sea lions square with an alarmist response from a University of Otago academic and its subsequent uncritical reporting in the Otago Daily Times.
The answer is it doesn’t.
Department of zoology scientist Dr Nic Rawlence was quoted in the ODT this week saying that unreported sea lion bycatch could wipe out the critically endangered species.
This was according to computer modelling used to measure the rapid decline of the Chatham Island sea lion (which was subject to hunting for its fur, oil and meat).
The researchers claimed there were 300 sea lion deaths a year attributable to fishing and this made up 30 to 75 percent of all mortalities.
Rawlence said that if 410 sea lions died every year for the next 50 years, the species would be extinct.
And if your grandmother had flippers and whiskers, you’d be taking an extreme interest in raw fish.
Fair dinkum. This is drawing an awfully long bow under the guise of scientific research that should have attracted a critical response.
Unless measures were taken to minimise bycatch deaths, the outlook for sea lions was bleak, Rawlence added. Hello. Earth to academia. Measures have been taken and they are being shown to be effective.
What is it about a coterie of Otago University academics that drives them to inflate the threat from fishing to everything from sea lions to dolphins?
It’s bad enough that they are so biased, it’s worse that they are funded by the very taxpayers they denigrate, with seemingly no accountability in pursuing their anti-fishing agendas.
The fishing industry has put a lot of time, money and effort into reducing seabird captures, in concert with the World Wildlife Fund, MPI and DoC through the Southern Seabirds Solutions Trust.
This has proved highly effective in protecting the huge numbers of seabirds in our zone. That good work is undermined by any commercial fishermen who do not apply mitigation devices that are proven to be effective in keeping birds away from baited hooks and from trawl warps and nets.
Non-compliance is not acceptable. The industry supports MPI action against offenders.
- Tim Pankhurst