Kina removal reaping rewards in Tōtaranui/Queen Charlotte Sound

Removing kina from sites in Tōtaranui/ Queen Charlotte Sound has encouraged the recovery of many significant rimurimu/seaweed and kelp species, the Environment and Planning committee heard recently.

Council’s Nautical and Coastal

Science team have been working with the University of Auckland who are monitoring experimental sites in the Sound. In a report prepared for the committee, Council’s Senior Coastal Scientist Katie Littlewood says rimurimu and kelp are both critical for ecosystem function and health as they create habitats for numerous marine species and also sequester carbon.

“Kina are endemic herbivorous grazers that feed on important rimurimu and kelp. An area can become overpopulated with kina, leading to kina barrens, which are areas completely cleared of seaweed and kelp due to over grazing,” Katie said. Dallas Lafont from the university research team spoke to the committee about the research.

“Seaweed species have been declining for 50 years due to overgrazing by kina, warmer sea temperatures and sedimentation,” Dallas said. “Species that predate on kina, such as large blue cod, snapper and crayfish, are low in number which allows kina to overpopulate and clear areas that were once full of healthy kelp and seaweed species.”

Four areas in Tōtaranui were selected to be part of the project and the extent of recovery and re-establishment of seaweed has been noticeable.

“After 18 months of monitoring the four experimental sites we have observed some degree of recovery at all sites. In particular, the return of hundreds of giant kelp (Macrocystis pyrifera) at one site,” Dallas said.

“While these results are exciting and kina removal is one useful tool to kickstart the recovery, the larger goal is to ultimately make these kelp forests self-sustaining, which will require further measures.”

This research has been carried out with support from Te Ātiawa and the Tē Tauihu Iwi Fisheries Forum and has been funded by Sustainable Seas and Port Marlborough.

Kina removal at an experimental site at Motuara Island has seen excellent results for recovery of kelp species - before (left) and after (right)