Samples from a stranded dolphin which died off Castle Island have been sent overseas in a bid to discover the cause of death.

The poorly Atlantic bottle-nosed dolphin was discovered in the water on Tuesday, but died after a combined rescue team from Dolphin Quest and the Bermuda Aquarium, Museum and Zoo (BAMZ) tried to move it to the safety of the Tucker's Town bay area.

Workers from BAMZ went out to the area after a call from a construction worker and, upon recognising that the creature was a dolphin, called Dolphin Quest , said Dolphin Quest general manager Christine Mihelcic.

"We dispatched an emergency medical team," said Ms Mihelcic. The team consisted of Roma Hayward, Dolphin Quest supervisor of marine animals and veterinary technician; Dolphin Quest staff Tim Hasselbring, James Davidson, Michele Morris-Demes, Katie Rice, and German intern Zena Derkum.

"It was fantastic how everyone pulled together," said Ms Mihelcic. "First they went out and assessed the situation."

The three-man team from BAMZ were still present in a boat as the Dolphin Quest team took to the water.

Ms Mihelcic said the dolphin appeared to be "lethargic", and that workers were surprised at how receptive he was to their presence. "We wanted to exercise caution with such a large animal, but were surprised at how we were allowed to go up and hold on to him. We knew at that point he needed medical attention."

To contain the ten-foot, six hundred pound dolphin, Dolphin Quest placed nets in the water before administering medication.

"After taking blood samples and assessing the elements and location, we decided we would move him around to the Tucker's Town bay area," said Ms Mihelcic. "Brian Mewitt, general manager of Mid-Ocean Club, allowed us to transfer him into the bay area, as well as use the security hut, electricity, hot showers - the team had been in the water for about five hours at that point, and it was a little chilly."

However, said Ms Mihelcic: "Unfortunately during that rescue the dolphin did die. We did attempt resuscitation, but he did pass."

Now the team faces a necropsy, the equivalent of an autopsy, of the dolphin to discover the cause of death. "We don't have concrete evidence as to what was the driving factor in his death," said Ms Mihelcic. "We are currently in the process of sending out samples here and abroad to our other partners.

"We hope that within a couple of weeks we should have some answers."

The Dolphin Quest team was obviously upset at the loss of the dolphin, said Ms Mihelcic. However, she added, it was very gratifying to see the way the team pulled together, both out on the water and back at base with setting up medical pools in case the dolphin had to be taken out of the water.

"We have attended other cases of stranded creatures before, but not of this species," she said. Dolphin Quest assisted in the rescue of a rough-toothed dolphin in January of 2000, and a stranded hooded seal, in the summer of 2001.

Currently Dolphin Quest has eight dolphins, including a female named Bailey who is pregnant.