'Kina barrens' target of new engineering innovation

Kina barrens have expanded across the Hauraki Gulf over the past 50 to 70 years, driven by an overabundance of kina (sea urchins) that consume kelp and remove critical habitat for marine life.

Diver-based culling - where divers manually crush kina directly on the seabed - can restore kelp within two years. But current methods are labour-intensive, physically demanding and difficult to scale across the gulf.

A new Next Foundation-funded project led by the University’s Faculty of Engineering and Design is bringing together engineers, marine scientists and divers to tackle this challenge.

The project will develop technologies across four interconnected areas: improving diver-operated tools, developing semi-automated removal systems, enhancing underwater ecological monitoring, and investigating future robotic solutions for large-scale restoration.

Associate Professor Andrew McDaid will lead the first two workstreams, with Dr Mark Jeunnette leading ecological monitoring and Dr Jaspreet Dhupia leading the robotics workstream.  

The project is being delivered in close partnership with the Faculty of Science and Leigh Marine Laboratory, whose marine scientists are already undertaking kina removal through diving operations.

They will be key end-users, testing and refining the technologies as they are developed.

"There is a real opportunity to use mechanical engineering and robotics to make sea urchin removal faster, more effective and scalable," says McDaid.

The research will address practical challenges including breaking kina shells so biomass can return to the food web, reaching kina in complex reef environments, reducing repetitive strain and injury risk for divers, improving visibility of already-culled kina, and developing robust tools that can withstand harsh marine conditions.

Engineers will also work to improve underwater data capture and real-time positioning, enabling more accurate and efficient ecological monitoring.

"We’re proposing a phased research programme that delivers both near-term impact and long-term transformation, progressing from improved diver-operated tools to powered devices, and ultimately to fully autonomous robotic solutions," says McDaid.

Restoring kelp forests requires more than 90 percent of kina to be removed from affected areas.

Successfully restoring these ecosystems would improve habitat and biodiversity, support the recovery of fisheries, increase blue carbon sequestration, strengthen cultural connections to the marine environment and build resilience to climate change.

"By applying engineering innovation with ecological expertise, this project will enhance the long-term resilience of New Zealand’s coastal environment," says McDaid.