The death of a "relatively young" bottlenose dolphin found Saturday in Venice Inlet likely was caused when the animal swallowed fishing gear, according to Mote Marine Laboratory.
Scientists at the Sarasota marine facility said the death spotlights the ongoing problem of human interaction with mammals, "a reminder to keep waterways clear of fishing line and other trash that can harm marine animals."
The 27-year-old female was part of a year-round population of bottlenoses in and around Sarasota Bay, according to the Sarasota Dolphin Research Program. The scientists have monitored the dolphin since 1985 and referred to it as FB93.
A Sarasota County sheriff's deputy spotted the dolphin floating between Venice and Casey Key. He contacted Mote, which retrieved the carcass for examination.
According to a necropsy, the dolphin most likely died from asphyxiation after swallowing fishing line, which was wrapped tightly and in a slip-knot around her goosebeak, a flexible tube connecting the blowhole to the lungs.
"The line was stretched taut and connected to a hook embedded in the dolphin's melon (forehead)," Mote said in a news release.
Scientists said the dolphin appeared to be in excellent condition before she died.
"She was one of the largest resident females of Sarasota Bay, at nearly 9 feet long and 471 pounds, and her stomach was full of fish," said Randall Wells, director of the Sarasota Dolphin Research Program.
Wells' team had documented that FB93 was born to Squiggy, one of the bay's resident dolphins, and had given birth to six calves. Squiggy, 56, as well as FB93's 20-year-old brother and 3- and 6-year-old calves still live in the bay. Her most recent calf, born in June, has not been found and is presumed dead following FB93's death.
Wells' program, a collaboration of Mote and the Chicago Zoological Society, has monitored and studied the Sarasota Bay dolphin population for 42 years. Halting dolphin-human interaction is a focus of the researchers.
The dolphin program has documented that many of the animals have been harmed or killed through negative interactions with humans, including boat strikes, illegal feedings and the ingestion or entanglement with fishing gear.
Of 10 dolphins stranded or found dead this year, three showed signs of human interaction, including the well-known Beggar, which developed a habit of accepting food from humans after being fed illegally many times. Beggar was found dead in September with broken bones and other injuries related to boat strikes and the ingestion of fishing equipment.
Bottlenose dolphins are protected by federal law.