Mr Pink, a charismatic sponge who lives under the sea

IN THE PINK: A new species of sponge found growing on the Astrolabe Reef. PHOTO/SUPPLIED

A "charismatic" new species of sponge nicknamed Mr Pink has been discovered on Astrolabe Reef by a scientist studying the ecological impact of the Rena wreckage.

Phil Ross, a marine ecologist from Waikato University, photographed the sponge while diving around the wreck and sent the image to Professor Chris Battershill who heads Tauranga's Coastal Marine Field Centre.

Several other sponges he photographed were less colourful.

"Mr Pink is charismatic, the others are more grey-looking."

The discovery of Mr Pink, yet to receive a scientific name, was announced to the world during the hearing on the application to leave the wreck on Astrolabe Reef (Otaiti).

His announcement, accompanied by a photo that highlighted the sponge's dazzling pink colour, was a fascinating diversion from the parade of expert witnesses fielded by the applicant before it concluded its case yesterday - ending five weeks of hearings.

Dr Ross told the Bay of Plenty Times Weekend he took a bunch of photos of sponges that he was unable to recognise, saying there could be at least two more species unknown to science.

He said there was a huge scope for discovering new species of sponges once you started looking.

"Once we get done with this [the hearing], we can bury ourselves in jars of sponges," he said.

The chemical compounds in sponges were being harnessed for breakthroughs in medical treatment, including a Kaikoura sponge proving useful as a breast cancer drug.

Dr Ross told the hearing there was no evidence of significant ecological effects outside of what was formerly the Rena's major debris field. The applicant had made a commitment to recover copper clove which was a contaminant of concern.

"Monitoring had been successful to date in identifying where copper clove is and we will continue to monitor for copper clove in the future."

Dr Ross said experts had agreed there was little tributyltin (TBT, a contaminant in ship anti-fouling paint) left on the bow section of the ship.

He also said abandoning the wreck was unlikely to make things worse or undermine natural recovery through more TBT.