A Marlborough teenager has been sentenced to two years in prison after clubbing to death 23 seals in Kaikoura last year.

Jason Trevor Godsiff, 19, of Renwick, admitted a charge in Blenheim District Court of wilfully ill-treating the seals by beating them to death.

He was sentenced this morning (Tuesday) by Judge Ian Mill.

The fur seals were beaten to death with a steel pole at Ohau Point, north of Kaikoura, late last year, the court was told.


Some of the dead seals were just a few days old. Other seals were injured, suggesting they too had been hit.

Seal Swim Kaikoura manager Matt Chambers welcomed Godsiff's two-year sentence.

He said it was fantastic to see authorities sending a clear message.

"This should count as a deterrent to anybody who has thoughts of going out to bash marine mammals, animals that we try so hard to look after," Mr Chambers said.

"We were gutted when this happened on our doorstep."

He said young fur seals are the most playful creatures in the ocean.

Mr Chambers, who has been working with seals for 24 years, described them as the puppies of the ocean.

"Dolphins get all the good publicity but seals are the most accessible to the public."


He said there are now estimated to be 300,000 seals in New Zealand waters but that is only about 15 per cent of the population that existed before commercial sealing began in the 19th century.

Department of Conservation south Marlborough area manager Dave Hayes said the sentence reflects the "high esteem" that people have for seals.

"Through-out the case we received lots of calls from people expressing their concern about what happened."

He said seals are often misunderstood and blamed for decreasing the fish stocks.

Mr Hayes said DoC is encouraging more research in this area but stomach content samples obtained so far show seals target lantern fish and squid _ not blue cod and snapper.