Dolphins Suspected in Porpoise Deaths

Researchers Puzzled as to Reason for Killings

Sixteen harbor porpoises were found washed up on Santa Barbara beaches in 2008. This number is up from an average of one or two per year, said Michelle Berman, the assistant curator at the Santa Barbara Museum of Natural History.

The growing number of dead porpoises remains a mystery to marine biologists. A total of 74 porpoise carcasses were reported to have washed up on California shores last year.

Scientists with Okeanis, a nonprofit conservation group based in Moss Landing, suspect bottlenose dolphins have been attacking porpoises because the bodies are found with rake marks and internal bleeding. In September, the group captured the only known video footage of bottlenose dolphins attacking a porpoise in Monterey Bay.

The video captured by Okeanis researchers shows a group of male dolphins corralling a porpoise, then smashing its body with their beaks and scraping and raking it with their teeth. The dolphins drown the porpoise by jumping on it, and then bring the carcass to the Okeanis researchers and swim away.

According to a report by the Santa Cruz Sentinel, the Okeanis researchers are unsure why dolphins would attack harbor porpoises. They ruled out competition for food as a factor, saying sea lions would be a more likely candidates for attacks if food were the issue. Berman added that there is no significant effect on the local marine food chain since the number of porpoises killed remains low.

Berman said Okeanis is seeking answers to the mystery of whether and why bottlenose dolphins might be killing harbor porpoises.

To submit a comment on this article, email or visit our Facebook page. To submit information to a reporter, email

event calendar sponsored by:

Goleta Target Store Confirmed

Set to open at Kmart location in 2019.

County Fire Chief Calls for More Fuel Breaks

Peterson wants to create a continuous front-country line from Montecito to Goleta.

Crime Rates Down, Youth Arrests Up in Santa Barbara County

A 'high percentage' of misdemeanor citations happen on school campuses.

Will Hollister Ranch Access Deal Hold Up Under Public Scrutiny?

State commissioners are taking a closer look at settlement over beach access to Santa Barbara County gated ...

Faced with a Gun, Sheriff’s Sergeant Holds His Fire

Sgt. Freddy Padilla reflects on potentially life-saving decisions during welfare call.