Sunday, August 16, 2009

FALSE ORCA

As a youngster I was a Member of the Whale and Dolphin Conservation Society. I loved to listen to whale song and read all about Marine Mamals. However I had never heard of the most recent guests to the Island. Last week a pod of 'false orca' were spotted off Cozumel. Here is a link to a video posted on utube by the Marine Park:

They look a lot like Dolphins and are actually part of the same family (delphinidae). BUT they are much bigger:

As its name implies, it also looks very similar to an orca and, like the orca, the False Killer Whale attacks and kills other marine mammals.

From Wikipedia:

The False Killer Whale has not been extensively studied in the wild by scientists; much of the data about the dolphin has been derived by examining stranded animals.

Although not often seen at sea, the False Killer Whale appears to have a widespread, if rare, distribution in temperate and tropical oceanic waters. They have been sighted in fairly shallow waters such as the Mediterranean Sea and Red Sea as well as the Atlantic Ocean (from Scotland to Argentina), the Indian Ocean (in coastal regions and around the Lakshwadweep islands) and the Pacific Ocean (from the Sea of Japan to New Zealand and the tropical area of the eastern side).

The total population is unknown. The eastern Pacific was estimated to have in excess of 40,000 individuals and is probably the home of the largest grouping.

The false killer whale and a dolphin have mated in captivity and produced a fertile calf.[3]. This is apparently the first mating between two different species that has produced fertile offspring, i.e., without postzygotic barriers. This offspring is called a 'Wolphin'.

The False Killer Whale has been hunted, but not extensively, in the West Indies and Indonesia. In Japan, a small number of these cetaceans are killed every year.

False Killer Whales have long caused anger amongst fishermen fishing for tuna and yellowtail. The dolphins take the fish from the longlines used by the fishermen. This led to a concerted effort from Japanese fishermen working from Iki Island to deplete the species in the area - 900 individuals were killed for this purpose between 1965 and 1990.[citation needed]

Several public aquariums in the world, including Seaworld Orlando have False Killer Whales on display.

Recent evidence indicates the insular population of false killer whales in Hawaii has declined dramatically over the last 20 years. Five years of aerial surveys undertaken from 1993 through 2004 have shown a steep decline in sighting rates. Group sizes of the largest groups documented in surveys were almost four times larger than the entire current population estimate [4].

On 2 June 2005 up to 140 (estimates vary) False Killer Whales were beached at Geographe Bay, Western Australia. The main pod, which had been split into four separate strandings along the length of the coast, was successfully moved back to sea with only one death after the intervention of 1,500 volunteers coordinated by the Department of Conservation and Land Management.

Just prior to sunrise on 30 May 2009, a pod of 55 False Killer Whales was discovered beached on a sandy beach at Kommetjie in South Africa (latitude 34° 8'3.98"S, longitude 18°19'58.22"E). By 9 a.m. already 50 or more volunteers had arrived to help swim out the whales into the ocean. Many more volunteers came throughout the day to offer their services. Late morning a decision by the authorities asked all volunteers to stabilize the False Killers Whales on the beach. No further attempt was made to take the whales into the open sea. At approximately 4 p.m. after considerable debate by all the authorities present, the decision was made to initiate euthanasia by shooting the whales; approximately 44 whales were killed. Fortunately, due to the efforts of the first volunteers in the early morning, some of the 55 False Killer Whales survived.

It clear from this event that not much is known about these mammals. Why they would find themselves in such a predicament? How long can these animals survive at the water edge? What options are there to get them back into the ocean? What are the options of handling these whales? How best to take care of these whales while rescue operations are put in place? What are the signs of stress in these mammals? How does one minimise the stress levels? How to keep the pod in communication?

We understand that these whales need to be turned on from one side to the other every 20 minutes to reduce pressure on their internal organs. That they need to be kept cool if in the sun and hydrated.

For example in the case of the beached whales in Sydney on 23-24 March 2009, the 11 survivors from a pod of 80 whales that beached themselves near Margaret River on Australia’s west coast were pushed back out to sea on the 24th. The long-finned pilot whales were loaded onto trucks at Hamelin Bay where they had come ashore the previous day for their release at a better spot 20 km away. Flinders Bay was picked because it is deep, sheltered and far enough from the original stranding site to deter the whales from coming back on shore. "There’s a juvenile in the middle of the pack as well, which is good", Department of Environment and Conservation officer Laura Sinclair said. "It’s looking more positive. They’re not meandering back to the coast." Margaret River schoolchildren were among the 200 volunteers keeping the whales wet so they didn’t dehydrate and die. Some stayed up all night to help in the rescue effort. Individuals measuring up to 6 metres long and weighing up to 3.5 tonnes were hoisted in a sling onto a truck for the trip from Hamelin to Flinders. They were penned until the pod was back together and then released together. From the above example. it is clear that whales can survive even road journeys if cared for properly.

The planning for the same incident: A spokesman for the WA Department of Environment and Conservation (DEC) said they were trying to herd the remaining group together to form a pod they hoped to entice back out to sea by the morning. DEC Incident Controller Greg Mair said veterinary assistance had been organised to assess the health and well-being of the remaining whales as well as equipment to try and take them back out to deeper water. “The main strategy is to re-group the animals, which are spread over five to six kilometres of beach, into one pod and hold them overnight in Hamelin Bay until day-break when they will be transported by truck to Flinders Bay for release,” he said. “This method has been chosen to ensure the whales’ greatest chance of survival,” he said. He added that a scientific team was collecting samples from the dead whales for testing as part of research into what causes whale standings. The DEC said long-finned pilot whales tend to strand both individually and in pods, and the last time the species stranded in WA was in 2005 when 19 beached themselves at Busselton. Of those, 13 were successfully returned to the ocean It is the second mass stranding of whales on Australian beaches this month.

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