Scientists critical of kina barrens plan
‘Vague and ineffective’ among criticisms levelled at proposed new fishing rules
Following Ocean and Fisheries Minister Shane Jones’ announcement of his plans to consider increasing the daily recreational catch limit for kina as part of new fishing rules to be enacted in time for next summer, scientists have come forward to voice their criticism, calling the plans “vague and ineffective”.
Last month, Jones expressed his confidence that the change would help the local communities finally tackle the longstanding issue of kina barrens, an area depleted of all life except for kina.
But local marine biologist Vince Kerr, who has spent decades studying kina barrens in Northland, said that the minister was “missing the point”.
“While removing kina treats the symptom, it does nothing to address the core cause of a sick reef. And that is overfishing.”
Kerr explained that a kina barren forms in the absence of their natural predators such as snapper, crayfish and rock lobsters.
Due to overfishing, the population of kina has increased “substantially” and over time large numbers of the native sea urchin would graze all the seaweed and kelp, leaving behind a bare reef.
While he appreciated the minister paying attention to the problem, Kerr felt the new rules wouldn’t produce the “desired results”.
University of Auckland research fellow Kelsey Irene Miller agreed.
“In some ways, it’s a simple problem. What’s not, is coming up with a simple solution.”
In her opinion, raising the daily catch for kina and allowing communities to harvest or cull made little sense since the process was extremely labour-intensive when practised on a large scale.
“Roughly, for culling kina, it takes about 50 hours per hectare and for pulling them out it’s probably closer to 100 hours per hectare.”
Citing her recent work in the Hauraki Gulf, Miller said after getting a special permit from MPI and support from local iwi, they had people go in and remove kina every few weeks on the two hectares of reef area.
Through continuous culling and monitoring, the researchers found that new kelp forests came to life.
“It was really effective as the reef went from 5 per cent kelp cover to 43 per cent in two years, which is a huge change.”
However, she warned against the use of culling since the method did not have any influence on the snapper or crayfish populations.
“My recommendation is if we can increase the density and the numbers of these predators, they can do the work for us, at least with kina,” Miller advised.
Although Fisheries New Zealand (FNZ) acknowledged both Kerr and Miller’s advice on the need to have a healthy population of predator species, they differed on the fact that removing excess kina would, in the long term, benefit predator species. Fisheries management director Emma Taylor said increasing the catch limits of kina was just one part of a suite of proposed management tools to support an “ecosystembased approach”.
She added that other measures like the two-year closure of fisheries in specified areas in Northland were supported by local hapū and would likely help improve numbers and size for species.
“The closure request was made under section 186A of the Fisheries Act 1996, which allows for a maximum temporary closure period of
two years.
“What we do is based on the best available information that suggests kina abundance is sufficient to allow for more to be harvested sustainably,” Taylor said.
Kerr argued that FNZ historically had a terrible “model management” which was outdated and had a “massive amount of assumptions”.
“Even the two-year closure that is set to be implemented isn’t going to be effective. As snapper and crayfish generally need around 10 years to recover.”
Kerr’s claim on fishing closure is supported by an Environment Court decision in 2022 involving Bay of Islands Maritime Park Incorporated vs Northland Regional Council.
The decision document said that all ecology experts agreed that the
“biomass” of snapper and crayfish was “seriously depleted”.
The species were seen as the main predators of kina on the northeastern New Zealand Coast. And that recovery of exploited species such as snapper and crayfish generally occurred within 5-10 years, the document said.
Kerr also pointed out another High Court Case decision in 2022 involving the Ministry for Primary Industries (MPI), which found that the 2021 and 2022 total allowable catch decisions for rock lobster in Northland were unlawful.
He said such cases demonstrated the inadequacy of the advice from MPI to the then Ocean and Fisheries Minister David Parker, who received ion on the kina barren crisis in Northland.
“I think a good first step for MPI would be to set up a proper technical advisory group because they have got to get their science right.
“And they need to consult with top researchers and iwi kaitiaki, who actually have done a lot of work on kina barrens and mapping,” Kerr said.
Miller also raised concerns about the growing number of a second species of kina called long-spined sea urchin, an issue also being looked into by FNZ.
“While predators like snapper love kina, they are not particularly attracted to these second kind. Overfishing has further helped them to increase multifold, a species that historically has been low in abundance. Hence, it’s worrying as we continue to research on this,” she said.
The Advocate also contacted Seafood New Zealand (SNZ), which represents commercial fishing interests.
An SNZ spokesperson said they were aware of the issue in Northland which was a “complex matter”.
“Science tells us that there are a range of factors which influence the prevalence of kina barrens. The science also indicates the snapper and crayfish stocks are in good health.”
SNZ said that the commercial fishing industry was considering how to lend a hand and was starting to have conversations with iwi and all community groups on possible pathways forward.