Shetland Islands Killer whales have been schooling off Shetland in record numbers, with up to 100 spotted by scientists feeding together at one time.
The lives and activities of the orcas are being catalogued by Andy Foote of Aberdeen University and Volker Deecke from the St Andrews Sea Mammals Research Unit. Their study is identifying the movements and feeding habits of the whale pods and trying to find out why there appear to have been more sightings in recent years. Some are drawn into the islands to hunt seals. One was seen bearing a fresh scar, apparently after scraping over rocks.
While accompanying a local fisherman, Mr Foote saw 100 killer whales feeding together. He was also able to identify a whale as the same one that was photographed in 1991.
One of the more frequently seen whales is Bigga, who is 7m long and was named after an uninhabited island between Shetland and Yell, to which he bears a passing resemblance. He usually lives alone, although he is sometimes to be found with a pod of five, including Busta, the leader of the group, and Ossa, the smallest member, who is thought to be either the younger brother or nephew of Busta.
maandag 21 juli 2008
vrijdag 18 juli 2008
Lone orca may have joined pod
Numerous sightings of orca pods around Auckland have given researcher Ingrid Visser new hope that the juvenile whale relaunched at Takapuna will be found with a group, probably further north in Rodney.
Dr Visser says she had about 100 phone calls on one day.
The whales have been seen at Kawau Bay, Snells Beach, Milford Beach and North Head.
Despite dedicating a whole day looking for her in the Hauraki Gulf the young whale has yet to be found.
"We spent day to day going from subgroup to subgroup but no little orca."
Three were seen off Milford Beach at about 3pm last Thursday afternoon by Glenfield resident Peter Ryan.
He estimated they were about 200 metres offshore.
"I’ve never seen anything so close."
Mr Ryan says he saw two together and a third further out.
"One was very large, you could tell by the size of its fin. I’m guessing they were chasing stingrays."
Dr Visser says there are at least three different pods in the Hauraki Gulf and the juvenile could be among any one of them.
Another is reported to be on its way from the Bay of Islands.
"We haven’t seen her yet, but it doesn’t mean she hasn’t joined one of these groups."
Dr Visser says killer whales can hear each other from nearly 20km away underwater, which makes it easier for them to meet up.
Dr Visser says she had about 100 phone calls on one day.
The whales have been seen at Kawau Bay, Snells Beach, Milford Beach and North Head.
Despite dedicating a whole day looking for her in the Hauraki Gulf the young whale has yet to be found.
"We spent day to day going from subgroup to subgroup but no little orca."
Three were seen off Milford Beach at about 3pm last Thursday afternoon by Glenfield resident Peter Ryan.
He estimated they were about 200 metres offshore.
"I’ve never seen anything so close."
Mr Ryan says he saw two together and a third further out.
"One was very large, you could tell by the size of its fin. I’m guessing they were chasing stingrays."
Dr Visser says there are at least three different pods in the Hauraki Gulf and the juvenile could be among any one of them.
Another is reported to be on its way from the Bay of Islands.
"We haven’t seen her yet, but it doesn’t mean she hasn’t joined one of these groups."
Dr Visser says killer whales can hear each other from nearly 20km away underwater, which makes it easier for them to meet up.
Killer whale flips seals out of water with its tail
Just when the seals thought it was safe to go back in the water . . . along came Bigga
He's an adult male orca or killer whale, about seven metres from nose to tail, weighing probably more than five tonnes and with a dorsal fin almost as tall as Portsmouth's new striker Peter Crouch.
In captivity an orca needs to down a daily 45kgs, equivalent to a small adult common seal. The appetite of a sea-going wild adult is much bigger.
In Whales of the World (1981), Lyall Watson refers to a report of an adult male found to have parts of 13 porpoises and 14 seals in its stomach - and another seal in its throat.
So when Bigga cruised menacingly into South Nesting Bay about 10 miles north of Lerwick, capital of the Shetland Isles, the fear that gripped the local seal colony was palpable.
"They were very aware of his presence and sensed that they were his target", said Andy Foote, an Aberdeen University postgraduate researcher working on the Scottish Killer Whale Project.
"As Bigga cruised up and down very close, staying out of the sea was their best survival strategy. At one point we saw a female with her flippers protectively around her pup, seemingly trying to make sure it didn't panic and slip into the water."
But three hours of patience finally paid off for the huge predator. The watchers realised this when a cloud of blood appeared suddenly on the sea's surface, then there was turmoil as the remains of the pup Bigga had just seized were flipped into the air by a powerful swipe of his tail.
"Killer whales often play with their food in this way", explained Mr Foote. "We don't really know why they do that - it's one of many mysteries that surround these fascinating animals."
Examples of this behaviour are given in Whales of the World: "We have seen a group in the Galapagos dismember a five metre manta ray by throwing it into the air."
Getting to know individual killer whales is an important part of the project engrossing Mr Foote and his colleague, Dr Volker Deecke, from the Sea Mammals Research Unit at St Andrews' University.
Once an orca is identified via photo, it is given a number and a name. Bigga - named after a whale-shaped island between mainland Shetland and neighbouring Yell - is also known as 014.
Often alone, Bigga sometimes joins the pod of five involved in last year's attack on a group of eider ducks that were flightless due to moulting.
That pod's big adult male has the number 032 and the name Busta - after Busta Voe. Its smallest member, a three-year-old numbered 067, has just been named Ossa, a location in north-west Mainland Shetland after public suggestions were invited.
With a different pod of eight reported this summer, the orca presence in Shetland is considered greater than in former times - and Mr Foote feels this is supported by an aspect of local folklore.
Shetlanders have special names for prominent local creatures - for instance the great skua, a rare seabird, is known as the bonxie, the black guillemot is the tystie and the common seal, the selkie.
"Perhaps significantly, however, there isn't a Shetland name for the killer whale", said Mr Foote. "That could indicate it has only been appearing regularly in Shetland waters in comparatively recent times."
If that is the case, one possibility is that it is linked to the disappearance of sand-eels from Shetland and Orkney waters since the 1980s.
Killer whales don't feed directly on them but their normal diet covers a range of creatures - sea mammals, birds and larger fish - that do. Has there been a change in hunting patterns due to the food chain disruption caused by the sand-eel absence?
maandag 14 juli 2008
Researcher hunts for orca
Numerous sightings of orca pods around Auckland have given researcher Ingrid Visser new hope that the juvenile whale relaunched at Takapuna will be found with a group.
Dr Visser says she had about 100 phone calls on one day.
The whales have been seen at Kawau Bay, Snells Beach, Milford Beach and North Head.
Despite dedicating a whole day looking for her in the Hauraki Gulf the young whale has yet to be found.
"We spent day to day going from subgroup to subgroup but no little orca."
Three were seen off Milford Beach at about 3pm on Thursday afternoon by Glenfield resident Peter Ryan.
He estimated they were about 200m offshore.
"I’ve never seen anything so close."
Mr Ryan says he saw two together and a third further out.
"One was very large, you could tell by the size of its fin. I’m guessing they were chasing stingrays."
Dr Visser says there are at least three different pods in the Hauraki Gulf and the juvenile could be amongst any one of them.
Another is reported to be on its way from the Bay of Islands.
"We haven’t seen her yet, but it doesn’t mean she hasn’t joined one of these groups."
Dr Visser says killer whales can hear each other from nearly 20km away under water, which makes it easier for them to meet up.
She would still like to hear from the public if they see any more orca whales and can be contacted on 0800-733-6722.
Dr Visser says she had about 100 phone calls on one day.
The whales have been seen at Kawau Bay, Snells Beach, Milford Beach and North Head.
Despite dedicating a whole day looking for her in the Hauraki Gulf the young whale has yet to be found.
"We spent day to day going from subgroup to subgroup but no little orca."
Three were seen off Milford Beach at about 3pm on Thursday afternoon by Glenfield resident Peter Ryan.
He estimated they were about 200m offshore.
"I’ve never seen anything so close."
Mr Ryan says he saw two together and a third further out.
"One was very large, you could tell by the size of its fin. I’m guessing they were chasing stingrays."
Dr Visser says there are at least three different pods in the Hauraki Gulf and the juvenile could be amongst any one of them.
Another is reported to be on its way from the Bay of Islands.
"We haven’t seen her yet, but it doesn’t mean she hasn’t joined one of these groups."
Dr Visser says killer whales can hear each other from nearly 20km away under water, which makes it easier for them to meet up.
She would still like to hear from the public if they see any more orca whales and can be contacted on 0800-733-6722.
UK National Whale and Dolphin Watch Results 2008
July 2008. The 2008 National Whale and Dolphin Watch produced some interesting results despite bad weather, especially in the north, according to Sightings Officer Edita Magileviciute.
Sixty manned sites were open to the general public, but watches were carried out in more than 165 locations around the country. A total of 339 sightings of whales, dolphins and porpoises were reported during the week, comprising of eight species, and sightings records continue to come in. Bottlenose dolphins were the most frequently seen cetacean with 146 sightings, whilst harbour porpoises were reported 106 times during the week. The third most common cetacean species was the Minke whale with 41 sightings. Other species spotted were Atlantic white-sided dolphin (6 sightings), short-beaked common dolphin (17 sightings), Risso's dolphin (6 sightings), killer whale (10 sightings) as well as a humpback whale.
Harbour porpoises
The results were comparable to previous years with harbour porpoises being the most widely distributed around the British coasts ranging from Orkney to Channel Islands, with concentrations mainly on the east coast of Scotland, Wales and South West of England.
Bottlenose dolphins
Bottlenose dolphins were reported off Northeast Scotland all the way down to the Channel Islands, with the Moray Firth and Southwest Cardigan Bay being the most common locations.
Common dolphins
Short-beaked common dolphins were observed more off the northeast coast of Scotland and Northwest Scotland than in their more regular haunts in South-west England and West Wales.
Minke whales
Minke whale sightings were observed in several areas of Scotland with the major concentration (30% of sightings) in the Northwest of Scotland and Outer Hebrides.
Atlantic white-sided dolphins
Atlantic white-sided dolphins were seen mainly off East Scotland between Aberdeen and Stonehaven. Risso's dolphin sightings ranged from Orkney to Anglesey in North Wales. There were no records from their usual range along the west coast of Scotland or the Isle of Man.
Orca & Humpback
Ninety percent of killer whale sightings were reported from Orkney and Shetland, with more sightings occurred this year than in any previous year of the National Whale & Dolphin Watch. The rarest species sighted was a humpback whale in Catfirth, Shetland.
Wales most popular
The region with the highest reported number of sightings was Wales with 98 sightings. Northeast Scotland had 79 sightings reported. Other regions with high numbers (20 or more) of sightings were Orkney and North Scotland, Cornwall, South Grampian, and North Grampian, Northwest Scotland and Outer Hebrides. Northeast Scotland had the greatest variety of species sighted, with six identified species seen during the week.
Bad weather
Edita said:"The bad weather in some parts of the UK meant that many watches were cancelled or abandoned early. Even when watches were carried out, the sightings rates were down, as the likelihood of seeing cetaceans decreased significantly with poor visibility, rain, fog and high seas. However, In New Quay Bay, West Wales, we observed bottlenose dolphins almost every day despite rain, fog and gusty winds."
Notable sightings from this year's watch include:
• A Risso's dolphin spotted in the River Clyde, close to the centre of Glasgow.
• A group of approximately 100 short-beaked common dolphins in the Sound of Sleat, Inner Hebrides
• Groups of 18-40 short-beaked common dolphins off Caithness and in the Moray Firth, Northeast Scotland.
• Groups of 30-35 killer whales in offshore waters northeast of Shetland.
• A humpback whale in Catfirth, Shetland
Sixty manned sites were open to the general public, but watches were carried out in more than 165 locations around the country. A total of 339 sightings of whales, dolphins and porpoises were reported during the week, comprising of eight species, and sightings records continue to come in. Bottlenose dolphins were the most frequently seen cetacean with 146 sightings, whilst harbour porpoises were reported 106 times during the week. The third most common cetacean species was the Minke whale with 41 sightings. Other species spotted were Atlantic white-sided dolphin (6 sightings), short-beaked common dolphin (17 sightings), Risso's dolphin (6 sightings), killer whale (10 sightings) as well as a humpback whale.
Harbour porpoises
The results were comparable to previous years with harbour porpoises being the most widely distributed around the British coasts ranging from Orkney to Channel Islands, with concentrations mainly on the east coast of Scotland, Wales and South West of England.
Bottlenose dolphins
Bottlenose dolphins were reported off Northeast Scotland all the way down to the Channel Islands, with the Moray Firth and Southwest Cardigan Bay being the most common locations.
Common dolphins
Short-beaked common dolphins were observed more off the northeast coast of Scotland and Northwest Scotland than in their more regular haunts in South-west England and West Wales.
Minke whales
Minke whale sightings were observed in several areas of Scotland with the major concentration (30% of sightings) in the Northwest of Scotland and Outer Hebrides.
Atlantic white-sided dolphins
Atlantic white-sided dolphins were seen mainly off East Scotland between Aberdeen and Stonehaven. Risso's dolphin sightings ranged from Orkney to Anglesey in North Wales. There were no records from their usual range along the west coast of Scotland or the Isle of Man.
Orca & Humpback
Ninety percent of killer whale sightings were reported from Orkney and Shetland, with more sightings occurred this year than in any previous year of the National Whale & Dolphin Watch. The rarest species sighted was a humpback whale in Catfirth, Shetland.
Wales most popular
The region with the highest reported number of sightings was Wales with 98 sightings. Northeast Scotland had 79 sightings reported. Other regions with high numbers (20 or more) of sightings were Orkney and North Scotland, Cornwall, South Grampian, and North Grampian, Northwest Scotland and Outer Hebrides. Northeast Scotland had the greatest variety of species sighted, with six identified species seen during the week.
Bad weather
Edita said:"The bad weather in some parts of the UK meant that many watches were cancelled or abandoned early. Even when watches were carried out, the sightings rates were down, as the likelihood of seeing cetaceans decreased significantly with poor visibility, rain, fog and high seas. However, In New Quay Bay, West Wales, we observed bottlenose dolphins almost every day despite rain, fog and gusty winds."
Notable sightings from this year's watch include:
• A Risso's dolphin spotted in the River Clyde, close to the centre of Glasgow.
• A group of approximately 100 short-beaked common dolphins in the Sound of Sleat, Inner Hebrides
• Groups of 18-40 short-beaked common dolphins off Caithness and in the Moray Firth, Northeast Scotland.
• Groups of 30-35 killer whales in offshore waters northeast of Shetland.
• A humpback whale in Catfirth, Shetland
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