Dolpin Deaths Not From Viral Infections

12 January 2000

Testing Rules out Viral Infection as Cause of Dolphin Deaths

Extensive testing of organ samples from dolphins found in the Bay of Islands before Christmas has ruled out disease or viral infection as the cause of death.

Russell-based marine mammal monitoring officer Alan Fleming said experts at the Massey University Cetacean Investigation Centre had completed a preliminary analysis of the organ samples collected from the four dead dolphins found in the Bay of Islands just before Christmas.

“To date this analysis has not conclusively identified a cause of death but it is doubtful
that a disease or viral infection was the reason,” Mr Fleming said.

“This is on the basis that no signs were observed during the collection or analysis of the organ samples,” he added.

The four dolphins were discovered in the waters around Cape Brett in the days leading up to Christmas, causing concern among staff that others may be found. They included three common dolphins and one bottlenose.

“It is reassuring that we have been able to rule out the possibility of a viral infection as large die-offs of small cetaceans have been observed in other countries around the world.”

“In 1997-1998 a large die-off (approximately 800-1000 dolphins) occurred on the Atlantic US coast, an event probably caused by a morbillivirus,” Mr Fleming said.

The Department of Conservation is still investigating other possible causes for the deaths including fisheries by-catch or an association with the oil spill at the Poor Knights two weeks before the dead dolphins were found.

Mr Fleming said however that no oil residue had been picked up so far although the department was keen to either disprove or verify an association with that event.

DoC staff have spent time on the water over the summer to ensure the public is well informed about the issues surrounding dolphins, their ecology and needs.

For more information please contact Alan Fleming on (025) 293 0069 or (09) 403 7685

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