environment

Skipper sounds alarm over Bluff oysters

An alarming drop in the Bluff oyster catch has prompted a veteran skipper to go public with his concerns that Foveaux Strait is being fished unsustainably. David Williams reports.

Over 45 years at the helm of an oyster boat, Anthony Fowler has seen it all in Foveaux Strait, including the closure and partial closure of the fishery after huge die-offs in the 1990s and 2000s. But he’s distressed by this year’s dramatic drop in catch numbers – in what is supposed to be a healthy fishery, boasting hundreds of millions of adult oysters.

“Put it this way, we’re getting half of what we caught last year,” he tells Newsroom. “Last year at this time we were getting 40 to 50 cases a day. This year we’re getting, like, 20.”

Fowler says he’s speaking publicly out of duty as kaitiaki of the Hokonui Rūnanga and to let the people of Bluff know what's happening.

When the season opened on March 1, few Bluff oysters were sent outside Southland, something that was put down to high demand.

But Fowler, who joined the Bluff oyster industry in 1968 and became a skipper four years later, says he’s never seen fishing conditions to be so bad. There’s also a high “reject” rate in the processing factories, where poor quality oysters of legal grade aren’t meeting expectations for size and colour.

Fowler blames the Foveaux fishery’s depletion on key industry figures – including the Ministry for Primary Industries (MPI), Crown science organisation NIWA (the National Institute of Water and Atmospheric Research) and the Bluff Oyster Management Company. He says they’ve allowed oyster dredging to continue, depleting the adult numbers and stressing the young ones being thrown back, despite years without significant numbers of baby oysters, or spat, being present.

Fowler believes the fishery should be closed to give it time to recover.

“To me, it looks like it’s on its last legs,” Fowler says. “The minister should be looking at this. It’s crazy. It’s just gone on and on.”

(A spokeswoman for Fisheries Minister Stuart Nash says officials haven’t advised the minister of any issues regarding the 2018 season.)

Foveaux’s plummeting catch is yet another blow for an industry that was last year rocked by the outbreak of oyster parasite bonamia ostreae on Stewart Island, which led to the removal of oyster farms in Big Glory Bay.

Last year’s scientific survey of Foveaux oysters estimates there had been a 47 percent drop in adult size oysters since 2012. But there’s still an estimated 364 million so-called recruit-sized oysters – plus 385 million “pre-recruit” and “small” oysters.

Those estimates leave Fowler scratching his head. “The numbers never ever stacked up to me. The scientists are coming up with all these millions and millions of oysters out there yet we can’t catch them. What are they saying, that people can’t catch oysters or something? But it’s not that at all, they’re just not there.”

Lower rates confirmed

NIWA scientist Keith Michael, who led the 2017 Foveaux survey and has studied the fishery for more than two decades, confirms this year’s lower catch rates. “I’ve spoken to a number of skippers and they’re saying they’re probably almost down to half the catch rate of what they would have started last year.”

But he maintains there’s no risk to the sustainability of the fishery – that commercial fishing has very little effect on the overall oyster population in the strait. What’s happening is an availability problem, he says, rather than an environmental one.

“Within two years they should start to see a real change in catch rates.”

The scientist says the fishery is at the bottom of a long decline. It’s been ravaged by the endemic disease bonamia exitiosa, which peaked in 2015. On the growth side, there’s been “low recruitment” – the replenishment of oyster spat – since the summer of 2009-2010. High-density patches “are gone now”, he says, with oysters more evenly spread over a wider area.

Hope for a bounce back is three-pronged.

The summer mortality from bonamia exitiosa is at historic lows this year, at about three percent. The recent annual survey showed huge increases in oysters of all sizes, including a 36 percent increase in “recruit size” animals. There’s also “massive” recruitment, Michael says, with high levels of spat and “wings” attaching themselves to adults oyster shells. That’s great for the future of the fishery but causes headaches for oystermen, who are forced to throw many adult-sized oysters overboard to give them a chance to grow.

The picture, then, is of low densities of oysters, lots of poor-quality fish, with many shells covered in spat, which means they can’t be landed.

“That’s the worst possible scenario for an oyster skipper and crews, because they’ve just got to work so much harder to make a catch,” Michael says.

“We acknowledge and appreciate that the fishing activity is very, very hard for the fishers, but in terms of risk to the stock, the science tells us that we’ve got good recruitment, low mortality, our models project that it’s going to rebuild reasonably quickly.”

(Fowler says there is spat on oysters this year, but it “comes to bugger all”. And while the fishery has the ability to bounce back, he says the lack of bonamia this year leaves little reason for the dramatic drop in the catch rate.)

Huge research spend

Bluff oysters are among the most monitored fish species in the country, thanks largely to hundreds of thousands of dollars spent by the industry each year. But the numbers signify a sorry story of decline.

In 1989, Foveaux’s catch limit was 89 million oysters. Four years later, after a devastating bonamia exitiosa outbreak, the fishery was shut to allow it to recover.

Since reopening in 1996, the total allowable commercial catch has been 15 million. However, the industry has agreed to take lower voluntary limits for the good of the fishery. This year’s take is expected to be 10 million.

Another key metric for oyster boats is the reported catch rates, measured in sacks per hour. (A sack is about 800 oysters. Fowler’s “cases”, mentioned earlier in this story, hold 400 oysters.) The reported catch rate hasn’t been above 10 since 1989. And while the rate increased to 5.5 sacks per hour in 2013, in a year when 13.2 million oysters were taken, the rate fell to 2.9 last year.

If this year’s rate holds, and falls below two sacks per hour, it’ll be the lowest rate recorded since at least 2006.

Part of the problem, of course, is comparisons with how abundant the fishery used to be.

“In the late 1960s and ‘70s there were that many oysters you could friggin’ near walk across Foveaux Strait,” says Graeme Wright, operations manager for Bluff Oyster Management Company, which runs the fishery on behalf of the 16 quota owners. Wright is also the manager of Barnes Oyster Ltd, whose factor processes about 60 percent of the Foveaux quota. Barnes Oyster’s shareholders include industry heavyweights such as Sanford, Skeggs Group, United Fisheries and Independent Fisheries. It runs eight of the 11 oyster boats in the fleet.

Wright says this year’s catch rate is behind 2017 but he doesn’t think the drop will be half across the fleet. “It’s a wild fishery and it has some ups and downs.”

He takes Michael’s line that while the catch is at a low point but there are positive signs it’s going to recover.

“I’m not saying the fishery’s in great condition, it’s not. We’ve had year-on-year mortality, we’ve had little recruitment. But this year and last year we’ve had the lowest mortality from bonamia than we’ve seen in a long time.”

“This is the pattern with almost every fishery in every part of the world ever – it is over-exploited to the point where it becomes commercially extinct.” – Craig Marshall

Concerns over commercial fishing in Foveaux Strait have been raised for years – by experts, fishermen and laypeople. Some worry about the effect on dredging on habitat and young oysters. Others bemoan the loss of once-dense oyster reefs and what that means for spawning.

Biochemist Craig Marshall, an associate professor at the University of Otago, wonders if the right scientific questions are being asked, something he has raised with Fisheries Minister Nash.

While Marshall doesn’t have data to confirm over-exploitation, he says the dropping catch rates suggest it’s happening.

“This is the pattern with almost every fishery in every part of the world ever – it is over-exploited to the point where it becomes commercially extinct,” he says. “I think there are some uncomfortable truths that may need to be faced.”

NIWA’s Michael says its research is fully open, transparent and robustly peer-reviewed. The public is consulted on its strategic research plan, with reports published by MPI.

If the commercial fishers are hell-bent on fishing at all costs, they would take their full quota of 15 million oysters every year, Michael says. “It’s very easy for people to make assertions about things that don’t seem right. But if people took the time to actually look at data and try and understand what’s happening then they may have a very different view.”

Looking at data hasn’t helped oyster boat skipper Fowler, however. He says the fishery’s being run into the ground because the management’s done based on scientific numbers that aren’t correct. “There’s a whole lot of bullshit going on somewhere. Somebody’s not doing their job, for sure.”

On Wednesday afternoon, MPI's director of fisheries management Stuart Anderson said the ministry had no immediate concerns over the Foveaux Strait dredge oyster fishery. “A catch limit is in place to ensure sustainability of the harvest. The fishery is regularly assessed by scientific surveys. A survey of the fishery has just been undertaken with results available soon.” Anderson said a meeting was held last night in Invercargill with iwi, recreational and commercial fishers. “There was nothing in the discussions with fishers yesterday that would suggest MPI should change its level of concern over sustainability of the fishery.”

* This story has been updated with comment from MPI.

Do you know more about this story? Email: [email protected]