Rimurapa/bull kelp, is an 'at risk/declining' species. Photo: RNZ / Alison Ballance
Repeated marine heatwaves have seen most 'old growth' kelp beds along the Coast Road between Greymouth and Westport disappear or dwindle in the past 20 years.
"The 2022 marine heatwave event has probably added to die-off that reportedly occurred following the Cyclone Fehi marine heatwave in 2018," according to a report to the West Coast Conservation Board.
The plants that had dwindled were less than 1m tall.
The die-off of rimurapa/bull kelp, an 'at risk/declining' species, at the Punakaiki Marine Reserve has gained significant attention nationally this year.
The decline in the past two decades from photo points taken in 2004 and 2018, and repeated this October, confirmed that most 'old growth' kelp beds on the coastline have "disappeared or dwindled to patchy regrowth".
Department of Conservation Hokitika area manager Owen Kilgour told the board meeting work was now being undertaken by the universities of Canterbury and Otago in collaboration with Niwa and DOC to understand the current status of bull kelp.
Research is being done into the status of bull kelp. Photo: RNZ / Alison Ballance
The study would look at the broader West Coast coastline, not just Punakaiki.
DOC Western South Island director Mark Davies said they were monitoring the five marine reserves, not the general marine environment.
The latter was the mandate of the West Coast Regional Council and the Ministry of Primary Industries. DOC's focus on the marine reserves only was within the limits of its statutes.
Meanwhile, a staff report noted the recent conviction of a commercial fishing company for bottom trawling through the Punakaiki Marine Reserve in April 2022.
The company was fined $12,500 and the skipper sentenced to 40 hours of community work.
"Fisheries NZ (MPI) detected the offence and led the prosecution, with assistance from DOC."
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