Saturday, July 28, 2007

Dolphin dies in captivity!

Brought to Chicago two years ago in hopes that he would impregnate the Shedd Aquarium's four female Pacific white-sided dolphins, an aging but proven dolphin sire named Jump died Monday in an off-view medical pool.Jump was at least 30 years old—at the high end of known life expectancy for white-sided dolphins— and probably succumbed to age-related ailments, Shedd officials said.He had been in periodic poor health for the last year.

"Sunday night, our trainers noticed he had a higher-than-normal rate of respiration," said Ken Ramirez, chief trainer at the aquarium. "I came in and spent the night with him and several other staff."

The dolphin showed signs of being in pain, so veterinarians gave him analgesics, he said."About 3 a.m. I asked him [Jump] to come to the side of the pool so we could do an ultrasound and take some blood samples, which he quite willingly did," he said. "The vet thought something wasn't quite right in the ultrasound pictures, but we couldn't tell what it was.

He just got weaker and died about 10:45 a.m."Preliminary results from a necropsy, or animal autopsy, seemed to support age-related failure of internal organs, Ramirez said, "though no clear picture emerged of what pushed him over the edge." More detailed results from tissue samples should be available in about three weeks.Jump had been one of the more successful sires in the early attempts to establish a captive breeding program for Pacific white-sided dolphins. He spent much of his life at Sea World in San Antonio, where he was responsible for "most" of that facility's six or seven successful dolphin births.

Despite his advancing age when he came to Chicago in 2005, Jump was still considered a viable sire. Scientists at the Shedd hoped he would mate successfully with the aquarium's four females, but they also wanted to do studies on Jump's semen in connection with the Shedd's artificial-insemination experiments. Jump mated frequently with the females during his first year at the Shedd, but no pregnancies resulted.In his last year, Jump's vigor began to wane, said Ramirez, and the dolphin showed diminished interest in the females as he began to suffer a series of illnesses.

"Over the last year he had a series of low-grade infections," Ramirez said, "but he always seemed to bounce back with antibiotics. They were all small illnesses, things you equate with geriatric issues you see in people. A slight cold for a healthy person can become something serious for somebody of advanced age."Keeping close tabs on Jump's health in his last year offered valuable experience in dealing with geriatric marine mammals, said Ramirez.Only 19 Pacific white-sided dolphins live in four North American facilities.

Eight are fairly recent captive-born animals, but the rest are older wild-caught animals, including the Shedd's four females, all in their 20s.Because a captive population of that size can't sustain itself and grow, the four institutions keeping the dolphins are considering several options to make the population more viable. They could collect more animals from the wild but seem intent for the time being to try other options, either bringing in animals from foreign collections or collecting semen from overseas animals for artificial insemination.

The Shedd has never had a successful dolphin birth. It has had four adults die since it first brought them here in the early 1990s. Its only two pregnancies, both the result of artificial insemination, failed. One calf was stillborn; the other died a few days after birth.Ramirez said Jump last performed in the Shedd's public programs a week and a half ago. Being older, the dolphin "didn't have an interest in doing lots of jumps and fast swimming behaviors," Ramirez said.

"He liked to participate in the shows . . . but he stayed on the perimeter instead of doing the high-energy things.""Jump's reason for coming here was for semen testing and our breeding program," said Ramirez. "We learned a lot about the transition to old age in his species from him and how to deal with aging animals. It has been the best part of having him with us for the two years that he was here."

Quick "Facts about Dolphins"