J.D. van der
Table of contents
Joe and Rosie
Echo and Misha
Into the Blue: Rocky, Missie and Silver
Marine Park dolphins
Bogie and Bacall
Buck, Luther and Jake
Ariel and Turbo
This paper is a compilation of articles on cetacean releases, originally written for the EAAM Newsletter. The texts have been updated to reflect the latest information about the animals involved. Additional references have been added and links to web sites with related information have been included.
The release of captive cetaceans back to the wild is an issue that is discussed more and more often. This discussion has intensified after the movie "Free Willy" appeared. Often, the release of captive cetaceans is portrayed as a straightforward procedure that is a logical solution for the controversy surrounding the keeping of cetaceans in captivity. (It is interesting to note, that the controversy focuses on cetaceans and is hardly ever extended to other marine mammals).
There are several types of release events, each requiring a different approach:
This paper deals with the latter category.
In this context, it is a good idea to look at what has been documented about earlier releases. In a list compiled by Ken Balcomb for the Center of Whale Research (Balcomb, 1995) in Friday Harbor, 58 bottlenose dolphins release events are mentioned and 20 killer whale release events. Of those so-called releases, only 12 cases involved the active release of bottlenose dolphins that had been in captivity for a year or longer. There was only one such case for killer whale and for that case no documentation is available and no follow-up was performed. All the other release events were:
The first 2 have no relevance with respect to the release of long-term captive cetaceans, since these animals have not been adapted to the captive situation so a readaptation to the wild prior to the release was not necessary. Of the last (the "escapees") usually no confirmed sightings occur after their "release".
A few releases have been documented to some extent and these we will examine a bit closer. For each, literature and web references will be given if available.
Joe and Rosie were captured in the Gulf of Mexico off Mississippi in 1980. They were the subjects of JANUS experiment by John Lilly and the Human Dolphin Foundation. Lilly stated that: "he had pledged to return them to the society of wild dolphins after five years of interacting with humans in captivity". In preparation, they were transferred to the Dolphin Research Center in Grassy Key, Florida on September 9, 1984. As it turned out, Rosie was pregnant at the time. Her calf was born on December 3, 1984. Unfortunately, the calf died on December 7, 1984. On March 11, 1985, Joe and Rosie were transferred to the swim program at Dolphins Plus in Key Largo, which marked the start of a number of moves back and forth between DRC and Dolphins Plus. In February 1987, Ric O'Barry, as a member of the ORCA team (Ocean Research Communication Alliance) officially took over the care for Joe and Rosie at DRC, although he was already involved before that (Personal note: my wife and I were at DRC from August 1984 through March 1985 and have seen O'Barry there to prepare the first move to Dolphins Plus). A blood test performed on April 22, 1987 showed that Rosie was pregnant again.
In June 1987 Joe and Rosie were moved to Georgia, to the site from which they were to be released. After the transport they were freeze-branded. On July 13 the gates of their holding facility in Georgia were dropped and they were released. On July 14, Rosie was spotted with a local pod. Later she was resighted with a group, but it was unclear if that was the same group. On July 15, Joe was spotted by himself, but in the vicinity of other dolphins. In the first two months after their release, they were sighted 8 times (confirmed sightings). (see Linden (1988), O'Barry (1988)). Despite the fact that both dolphins should be highly recognizable due to their freeze brands, no confirmed sightings have been documented after that. Consequently, nothing is known about the fate of Joe, Rosie or Rosie's baby after that. This release is a so-called non-native release, because the animals were released in an area that they would not be found in under natural circumstances, far away from their natural home range.
|Rosie at DRC, December 1984|
When Echo and Misha were captured in the Tampa Bay area in 1988, their future release was already planned. They were transferred to Long Marine Lab in Santa Cruz, where they were the subjects of echolocation studies. After a long readaptation process, they were released near the site where they were captured, in southeastern Tampa Bay, on October 10, 1990 under the supervision of Randy Wells and the Chicago Zoological Society. Echo was fitted with a radio transmitter, but this device failed within 2 hours post-release. The attachment came off in late October 1990.
In the first month, the dolphins remained together. They were seen integrated into a dolphin group on October 22, 1990 for the first time. Subsequently, Echo moved out of southeastern Tampa Bay and was spotted in Old Tampa Bay, close to his original home range, on September 3, 1991 (within 4 km from his capture site). All subsequent sightings of Echo (in 1991, 1992 and 1993), were in Old Tampa Bay, within 9 km from this capture site. He has not been sighted after 1993. Misha has been sighted numerous times from 1990 through 1996, within 11 km from his captures sites (Misha was captured, tagged and released in 1984).
The dolphins appear to have successfully acclimatised to life in the wild. They have not been observed to interact with humans. Systematic follow-up monitoring was considered crucial in identifying their successful acclimation. Factors attributed to this success appeared to be:
Rocky was collected in the Florida panhandle in 1971 and maintained at Marineland in Morecambe (UK). Missie was collected off Biloxi, Texas in 1969 and maintained at Brighton Aquarium (UK). Silver was collected in waters off Taiwan in 1978 and also housed at Brighton Aquarium. These animals had been in captivity for 20, 22 and 13 years respectively. A project group called "Into the Blue" took these animals to the Turks and Caicos Islands and released them there. It has been reported that Silver had a Candida infection when he was released. They were released on September 10, 1991. Silver has reportedly been spotted by the project team one to two weeks after his release. He had lost weight. He received food and medication. (There is a photograph of Silver, taken 1-2 weeks after his release. This picture shows a very emaciated dolphin. (Peter Bloom, pers. comm.)) There are no confirmed sightings of any of the three dolphins after September 29, 1991. A $100 reward for pictures of the released dolphins remains unclaimed. Ken Balcomb reported that undisclosed sources have seen Silver in the company of Jojo, a local friendly dolphin, in the Turks and Caicos in 1994. Since all animals were released far from their home ranges, this is a non-native release. According to Rice (1998), dolphins from the Taiwan area are a separate species: Tursiops aduncus, If so, the release of Silver could be considered an introduction of a non-native species.
In 1981, Atlantis Marine Park in Perth, Australia captured 7 bottlenose dolphins from its local waters. In August 1990, the park closed and attempts to relocate the animals failed. Therefore an attempt was made to release the animals. At the time of the release, on January 13, 1992, 2 adult females had died, but 4 calves survived, so a total of 9 animals were released. One of the females was pregnant at the time of the release; the youngest calf was 2 months old. All dolphins (except the newly born calf) were freeze branded. Prior to release, the 5 adult dolphins were fitted with radio tags to make tracking them possible. On January 13 the gates of the holding area at the release site were dropped, but none of the dolphins left. One of the animals, Rajah, left the area the next day. 5 days later he was resighted. He had lost a lot of weight and followed the boat to the pen from which he was released. He was returned to the pen to regain his weight. On January 16 the other animals left the pen, first as a group. Later the group split up. Echo, a juvenile was recaptured in poor condition after a few days. Mila was seen repeatedly with her calf. After 4 weeks the calf disappeared and was presumed dead. Mila was recaptured on February 28 and returned to the sea pen. The radio tags failed fairly soon, making the planned tracking of the dolphins impossible. There were a few sightings of animals with radio tags, presumably some of these dolphins, but that could not be confirmed. In summary: 3 dolphins had to be recaptured and were not released again, 1 (the calf) is presumed dead, the rest is unaccounted for although there have been sightings of tagged dolphins that might have been adults from this group.
Flipper was captured in 1981 in Brazil and was kept in a now defunct amusement park near Sao Paolo. The WSPA (World Society for the Protection of Animals) hired Ric O'Barry to release Flipper. He was released in 1993. He has been resighted several times. The most recent sighting was in March 1995 (he was filmed by a local TV crew in Sao Vicente, Brazil, and he was identified by his freeze brand). Reports of Flipper often mention injuries from fishing gear or rake marks. He is often seen near beaches, interacting with bathers and accepting handouts. Also he is often seen in the company of a group of tucuxi dolphins (Sotalia fluviatilis). His attention for people and the fact that he seeks the company of another dolphin species has raised some doubts about the adequacy of the pre-release preparations.
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