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International Science paper reveals collapse of Kelp beds

Media Release - Tuesday - 9 December 2014

NZ MARINE CATASTROPHE: International Science paper reveals ecosystem collapse of Kelp beds, replaced by urchin barrens.*

Noted marine specialist, Wade Doak, of Northland, New Zealand, says an important scientific paper, just published in the international Royal Society’s Philosophical Transactions, charts the widespread collapse and destruction of marine algal forests, the kelp beds, around New Zealand's and other countries' coasts. The paper includes the work of marine scientist Dr Nick Shears, of the University of Auckland.

Dr Shears says “The ecological balance has been lost with the widespread decline of sea urchin predators from over fishing. The loss of predators, such as snapper and large crayfish, that eat sea urchins (kina), has resulted in many coastal reefs suffering an explosion of kina populations and subsequent loss of the ecologically rich kelp beds. The result: underwater reefs dominated by sea urchins, but barren of the ecologically vital kelp beds which nourish and provide habitat for a wide variety of species.”

The twenty ecologists and other coastal scientists from several different countries and research organisations, show that this ecosystem phase shift has occurred on many coastal reefs around New Zealand and also on the reefs of those other countries.

Wade Doak, based in Ngunguru on the Tutukaka coast in Northland, and an observer since the 1950s of this ecological collapse, says " it is as gradual as a slow-motion train wreck; as destructive as an asteroid hit; longer lasting than an oil spill: the transformation of many of New Zealand’s coastal reefs into barren moonscapes is part of a planet-wide catastrophe. Over-exploitation of inshore waters by modern fishing techniques is to blame: large scale removal of sea urchin (kina) predators such as snapper and crayfish produces a trophic cascade where sea urchins thrive, but little else.

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Research from New Zealand reefs in this global study includes data from reefs throughout New Zealand, which found urchin barrens to occur at various locations from Cape Karikari in the north, to Patterson Inlet in the south.

Doak comments, “Many barrens are in top tourism areas such as the world rated Tutukaka Coast. Divers are sending me their observations and pictures from all over the country. Scientists can now also discern barren reefs from satellite images and Google maps.” [see attached media kit].

Vince Kerr says, “Once the kelp forest community has been replaced by an urchin/kina regime, it is very hard to restore the former, age old, rich undersea vistas. We must act to halt this decline. That means allowing the kina predators to return and with them the nourishing kelp beds.”

Roger Grace says, “Besides their diminished value for coastal fishing and kaimoana gathering, (barrens kina are unpalatable) the carbon fixing value of such vast areas of sea plants has implications for global warming and climate change - with consequences that parallel large scale felling of our forests.”

Wade Doak, Roger Grace and Vince Kerr agree and say, “the best option is to take urgent measures to arrest the decline of our reefs, now at the tipping point. Our thriving marine reserves offer us insights into how much is at stake and how these trends can be reversed through protection.”


*From noted Northland ecologist-diver-writer-film maker- photographer Wade Doak (with input from marine scientists Dr Nick Shears, University of Auckland, Dr Roger Grace (marine ecological consultant, Warkworth) and Vince Kerr(marine science consultant, Whangarei).

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