Echo and Misha Update: Misha’s death 16 years post-release
By Kim Bassos-Hull, MSc

Echo (top) and Misha (bottom) underwater view at Long Marine Lab, 1989.

It is with sad news that I report that Misha’s carcass was recovered on July 6, 2006, near Port Manatee in Tampa Bay. Misha was one member of a pair of dolphins that participated in a unique two-part scientific experiment. Echo and Misha were initially collected in Tampa Bay in July 1988 and spent two years at the University of California at Santa Cruz’s Long Marine Laboratory where researchers studied their echolocation processing abilities and behavior patterns. Then, as planned prior to collection, on October 6, 1990, they were released back into Tampa Bay after a transition process in a seapen at Mote Marine Laboratory. During intensive monitoring during the first year following their release, both Echo and Misha were observed feeding, interacting with other local dolphins, and in general displaying typical behavioral, ranging, and social association patterns as well as excellent body condition.

Misha during an echolocation trial at Long Marine Lab, 1990.

Echo and Misha split up after the first few months back in the wild, but researchers continued to observe both dolphins through opportunistic sightings. Misha had been sighted on 70 different days since release along the southeast coastline of Tampa Bay. The last sighting of Misha by our program before his death was on August 16, 2005, in the Manatee River (southeastern Tampa Bay) where he was observed with longtime associate, KATT. Echo has been sighted 55 times since release, the last several sightings by the Eckerd College Dolphin Research Program in the Boca Ciega region (western part) of Tampa Bay. Echo’s most recent sighting was on June 26, 2003, in upper Boca Ciega Bay.

Misha and Echo together two months after release in December 1990 .

Misha was freshly dead when his carcass was recovered by the Florida Fish and Wildlife Conservation Commission’s Marine Mammal Pathobiology Lab, but cause of death was not immediately obvious upon necropsy. It is suspected that he was suffering from an infection but histopath samples provided no clear insights into cause of death. He was in good physical condition and reproductively active at time of death. At 25 years of age, he had reached a length of 257 cm and weight of 223 kg, typical for males his age. Misha was found along the same section of coast where: 1) he was first tagged in 1984, 2) he was caught in 1988 and taken to UC Santa Cruz, 3) he was released in 1990, and 4) he was resighted most often following release. We hope to re-sight Echo in the next year with increased effort in the Tampa Bay area and additional collaboration with the Eckerd College Dolphin Research Program surveys.