Concern over drop in dolphin numbers

02:14, Jan 09 2014

Marlborough Sounds tourism operator Danny Boulton is calling for the removal of mussel farms in Admiralty Bay following a study pointing to the area's declining dusky dolphin population.

Researchers from the United States have found that the dusky dolphin encounter rate, average group size and individual re-sighting rate in Admiralty Bay, near French Pass, declined in the winters of 2011 and 2012 compared with 2005 and 2006.

Texas A&M University PhD candidate Sarah Piwetz, a member of the research team, said the reason behind the change in habitat use was unknown.

"It could be due to natural or other changes in habitat," she said.

Their data had not yet been fully analysed statistically or published in a peer-review scientific journal.

"As aquaculture has increased, the dusky dolphin population has decreased, and that should be cause for concern," Mr Boulton said. He called on the Marlborough District Council and the aquaculture industry to halt any further applications to establish mussel farms in the area. The government was placing economic advancement ahead of environmental balance, he said.

Admiralty Bay was a historically important foraging habitat for dusky dolphins, according to the research.

Potential contributing factors of the decline in dusky dolphins included the climate, human-generated disturbance such as intensive shellfish aquaculture and inter-species competition, the report said.


The Nelson Mail