Paua on verge of extinction

I realised that in areas I had dived 50 years ago, where there were thousands of very large paua, numbers of large specimens had declined sharply over the last 20 years to virtually total wipeout today. - Laurie Austen

A local man who has been studying the paua beds west of Ahipara's Te Kohanga (Shipwreck Bay) for more than a decade fears that, despite the best efforts of the the community to ensure sustainability, the species there is on the verge of extinction.

Laurie Austen, who remembers what gathering paua in the Tauroa (Reef Point) area was like 50 years ago, when a feed could be harvested almost without getting wet, said he had begun seriously studying the species 14 years ago, when he realised that there was a problem with declining numbers along a relatively short stretch of rocky coast, and no apparent signs of regeneration.

"The paua population in the Tauroa area was probably at a stable biomass max for countless years," he said.

"Maori gathering was by shallow water bobbing and harvesting of the kaimoana was strictly controlled by tikanga and rahui. The quantities of kaimoana in the Tauroa area 50 years ago were truly stunning."

Things began to change around that time though. The commercial harvesting of crayfish began, and about 30 years ago the numbers of divers, mainly targeting paua, began to increase rapidly. That increase in divers had continued exponentially, and unabated.

The situation had now reached the point where he believed the paua fishery should be closed until the problems of declining numbers and a lack of regeneration had been resolved. The alternative to that would be to watch divers wipe the species out.

"Although paua reproduce very efficiently in the laboratory environment, this is not the case in the wild," Mr Austen said.

"Three years ago the wise step was made to place a rahui on Otia Bay, followed up by an experimental reseeding of juveniles. The reseeding highlighted the lack of suitable environments (eg, boulders beds) for small juveniles. The west coast at its wildest can throw car-sized boulders out of pools."

Attending the World Abalone (Paua) Symposium in Hobart had made it abundantly obvious, by the multitude of steeply declining graphs of abalone populations worldwide and the lack of talk of recovering populations, that Tauroa's problem was not unique. Invariably, where populations had been decimated, recovery was non-existent or sparse.

"I realised that in areas I had dived 50 years ago, where there were thousands of very large paua, numbers of large specimens had declined sharply over the last 20 years to virtually total wipeout today," he said.

"Over that time I have observed virtually no recruitment of juveniles, leading me to the inescapable conclusion that the remnants of the populations are the same paua I observed 50 years ago. The situation at present is that the population of paua from Owhata to Otia is only a few 'diving days' from effectively being wiped out. That leaves us with the rahui area and the 4.5 kilometres of mainly stunted-growth population from Otia to Bluehouse."

The life cycle of paua saw juveniles settle and grow in sheltered areas of shallow water. As they grew they moved out to the limit of the kelp line.

"Ergo, there is no magical reef of paua off over the horizon. The kelp line is in an approximately maximum of six metres of water, and at Tauroa about a maximum of 100 metres offshore," he said.

And he suggested that those who continued to claim there were thousands of paua look at the simple mathematical equation.

On an average diving day (a day of relative calm and water clarity) there would be an average of 50 vehicles. Three divers per vehicle equated to 30 paua per vehicle, or 1500 paua being taken per diving day from Tauroa; 666 diving days would see 1,000,000 paua taken.

"I defy anyone to show me the thousands, let alone the millions, of juveniles needed to sustain this take," Mr Austen said. "Also, locals living around Tauroa are telling us that summer vehicle counts are often in excess of 100, so estimated numbers could be far too conservative.

SolutionsPotential solutions included the setting of new seasonal and sustainable take limits, the problem with that being public acceptance.

"Until people realise there is a problem they won't be accepting of change, and there would be the issue of policing," he said.

A large-scale reseeding would depend upon a supply of larger juveniles that would be big enough to get them past a range of predators, the "cons" there being expense, time and people taking them before they were mature enough to breed.

"West Australia has what are recognised as quite prolifically breeding abalone, but has an open season of only five days per year," he said.

"A voluntary reduction in the take and treating paua as a taonga rather than a commodity would be a good starting point."

Time was of the essence, however, and real solutions had to be found and implemented to save the paua population at Tauroa from catastrophe. And there could be more bad news on the way.

"To add even more pressure to the recreational take, over a tonne of commercial paua quota is currently being collected in Te Hiku," he said.

"Jeff Iken, Kaio Hooper and I made an inspection dive at Otia. We found a surviving, rather than a thriving population of paua, again with a lack of small juveniles. (The kina population shows real signs of recovery.)

"Some years ago a scientist from the Cawthron Institute told me that if I wanted to hear stories of healthy paua stocks I should talk to the people with a vested interest in selling that line of thought, ie, quota holders and poachers.

"This has been evident in the last few days; I am told by the Ministry of Primary Industries that commercial quota holders have put a case to decrease the size limit, allowing them to harvest stunted growth populations.

"This is being taken seriously by the Government, and without serious opposition will happen, as the paua industry is putting the value of this change at $33.6 million.

"If the current harvest is sustainable, why have exports declined steadily since 2001? Why are attempts to reseed being made nationwide? And why would there be a need to decrease the size limit in a healthy, sustainable fishery?

"My personal recommendation for the Tauroa area is that we should immediately explore ways to totally close the fishery until the problems of sustainability and regeneration can be resolved."