Displaying items by tag: basking shark
Basking sharks which were sampled off the west Kerry coast in early Spring have proved to be genetically different to all other such sharks tested in the north-east Atlantic, according to a newly published study writes Lorna Siggins.
The study on the migration routes of basking sharks also shows that the animals prefer to swim “en famille” to known feeding locations.
Researchers from the Galway-Mayo Institute of Technology (GMIT) participated in one of the most comprehensive studies of the genetics of one of the world’s largest fish.
The project findings, led by the University of Aberdeen, Scotland, were published this week in the journal, Scientific Reports.
Hunted off the south Irish coast by Norwegians until the 1980s, and off the west coast for the Achill fishery in the 1950s and 1960s, the basking shark is known among coastal communities as the “sunfish” due to its preference for swimming just below the surface.
It is also known as “liop an dá” (unwieldy beast with two fins) or more generally “liabhán mór”, denoting a great leviathan.
It is protected in some waters and was recently classified on the International Union for Conservation of Nature “red list” for endangered species
The plankton-eating fish is distinctive for its open mouth. It has been estimated that a seven-metre shark, cruising wide-mouthed at a speed of two knots, will filter 1,484 cubic metres of sea-water per hour.
Basking sharks can grow to more than ten metres, can dive to depths of more than a thousand metres, and feed on plankton in areas of the northeast Atlantic including the west coast of Scotland, Ireland and the Isle of Man.
The researchers note that “up until recently very little was known” about their biology, as they only appear briefly at the sea surface each spring before “vanishing into the ocean depths”.
Through establishing a register of genetic profiles with regular swabbing, the researchers were able to identify individual basking sharks when they arrived to feed. The results revealed that the fish repeatedly returned to the same feeding sites in successive years.
Fieldwork off Donegal by GMIT’s Dr Simon Berrow and Emmet Johnston of the Irish Basking Shark Study Group led to a “breakthrough” in sampling, by collecting skin mucus samples in large groups of sharks - quickly, and with minimum disturbance.
The researchers say that one of the “most surprising” findings among the “cosmopolitan” filter feeders is that basking sharks sampled off Ireland in spring were genetically distinct from other north-east Atlantic fish, including those sampled later in the year off Co Donegal.
An endangered basking shark showed up off North America three years after it was tagged in Ireland, according to new research published by Irish and Canadian scientists.
A female basking shark which was fitted with a satellite transmitter at Malin Head off north Donegal was photographed off the coast of Cape Cod all of 993 days later.
The study by researchers at Queen’s University Belfast (QUB) and Western University, Canada notes this is only the second time that transatlantic movement for the world’s second-biggest fish has been documented.
Basking shark were once hunted off the Mayo coast for their oil, and are now an endangered species risking extinction.
Lead author of the study, QUB PhD student Emmett Johnston has already recorded basking sharks engaged in “bursting” or breaching from the sea of Donegal, and counted some 600 such attempts over a 90-hour period.
"This new evidence offers invaluable information to help us better understand the movements of this endangered species"
The new study, published in the Journal of Fish Biology, noted that the last recorded evidence for transatlantic movement was gathered in 2008 when a female basking shark tagged with a tracking device moved from the Irish Sea to continental waters off the coast of Newfoundland.
“Over 1500 individual sharks have been equipped with either visual identification or satellite tags in the Atlantic to date, leading to just a single record of transoceanic movement, until now,” Mr Johnston said.
“This new evidence offers invaluable information to help us better understand the movements of this endangered species within an international context,” he said.
QUB senior lecturer Dr Jonathon Houghton noted that “for this animal to show up across the ocean three years after it was tagged in Ireland highlights that we really need an international mindset when seeking to conserve this species.”
Co-author of the new study Paul Mensink from Western University said that “in the era of big data”, it was “amazing how much these fortuitous re-sightings of individual animals can tell us about an entire species”.
Cork RS dinghy sailors Alex Barry, Sandy Rimmington and Andrew Welland shot some great video swimming off Roches Point, Cork Harbour up close and personal with some massive basking sharks. The footage (below) shows the plankton–only eating creatures feeding while the sailors swim around them. In a weekend of marine wildlife spottings there was sightings of breeching humpback whales off the Cork and Kerry coasts too.
#MarineWildlife - Do you remember the basking shark that surprised a group of bathers off Cape Clear last summer?
According to TheJournal.ie, it's now featured in a documentary shot on the fly by a team of quick-thinking filmmakers.
But in the process of filming, they happened to be close by when the basking shark - the second-largest fish in the oceans – made its appearance, the solitary beast almost a metaphor for the island's dwindling community.
TheJournal.ie has more on the story HERE.
The Irish Times yesterday posted video of the close encounter captured by Graham Smith while paddling along the coast.
As Smith told the Irish Independent, he was only hoping to catch a tope shark when he came upon a school of basking sharks off the Inishowen Peninsula.
And when one of them started following him, Smith went into panic mode - but soon realised the shark was more interested in the slipstream of his kayak, which provided a steady source of plankton for the giant filter feeder.
The second biggest fish in the sea after the whale shark, basking sharks are now a regular sight in Irish waters, with protections on the endangered species resulting in a boom in numbers.
The gentle giant - one of the second largest species of fish in the world's oceans - was beached early yesterday (15 July) after being sighted floating in the River Liffey.
Dublin City Council said it was making plans to remove the carcass from the popular seaside spot on Bull Island.
#shark – The journey of a basking shark has been tracked from Malin head, Co. Donegal to tropical waters west of the Cape Verde Islands, over 5000km. This is an exciting new
finding for the iconic shark species which visit Irish waters during the summer months. It was previously believed that the sharks that visit our shores only foraged in temperate waters.
'Banba' a female basking shark tagged in July with a satellite transmitter off Malin head, Co. Donegal has just released its transmitter west of the Cape Verde Islands, over 5000km away from were it was originally tagged. The five meter long female shark was one of five basking sharks tagged as part of the Monster Munch Basking Shark Community Awareness Project run by the Irish Basking Shark Study Group in association with the Inishowen Development Partnership and Queens University Belfast.
The movement by the shark 'Banba' into warm tropical waters off West Africa coupled with similar findings by leading American shark biologist Greg Skomal in the western Atlantic, questions the validity of the established theory that basking sharks inhabit temperate waters only. Previous basking shark tracking studies undertaken in the north east Atlantic have only recorded shark movements within temperate waters. The majority of tracked sharks have displayed a seasonal onshore - offshore migratory pattern, with movements of one or two hundred miles offshore onto the continental shelf edge during winter and return shifts to coastal waters during summer months. This seasonal pattern allows the sharks to feed year round on copepods a type of zooplankton, their stable food source. However the recording of this magnificent journey by a basking shark from Malin head to warmer tropical waters questions many of the fundamental theories marine biologists have regarding the species and its lifecycle.
Basking sharks were once hunted off the coasts of Ireland, but they are now classed as endangered in the North Atlantic. The Irish Basking Shark Study Group have been pioneering research on the iconic marine leviathan which can weigh more than an African elephant and grow to over 11m in length. In recent years the group have had internationally significant findings in DNA sampling, population surveys, tagging and tracking. The groups' motivation is to see the shark protected in Irish waters, one of the last western European territorial water bodies where they remain unprotected. Emmett Johnston a co-founder of the group spoke briefly about Banba's journey "The group are delighted with the finding, but it is a bit premature to be rushing out to change the shark biology books. We are awaiting the pop-off of the remaining three satellite transmitters attached this summer, recovering five complete basking shark tracks will allow us to compare the data and make informed conclusions. Until then there is not much we can say other than this is a highly unusual place to find a species that is presumed to inhabit temperate waters". The satellite transmitter tags used to track the basking sharks incorporate pioneering Fastloc GPS technology coupled with depth and water temperature sensors which will allow researchers to recreate the track of the shark in three dimensions.
Emmett added," Understanding where the sharks are and what they do when they are there, is essential to making informed management decisions regarding this endangered species". A number of years ago Dr. Simon Berrow a co-founder of the group noticed a parasite on the sharks called pannella when undertaking shark tagging off Malin head, this parasite is often recorded on cetaceans which have travelled through tropical waters so the group have had an inkling that basking sharks visiting Irish shores might have travelled through warmer waters prior to arriving on our coast. However in marine biology circles its one thing to propose theories and another to actually prove them.
The Monster Munch project was set up to bridge the gap between marine scientists undertaking research and the local communities in which the work is undertaken. The Inishowen Development Partnership, Queens University Belfast and the Irish basking shark study group funded the initiative which delivered a primary school based awareness programme encouraging local fishing dependent communities on the Inishowen peninsula in Co. Donegal to take ownership of the basking shark species and assist in its conservation.
Malin head on the Inishowen peninsula where the shark 'Banba' was originally tagged and named by pupils at Scoil Naomh Mhuire has recently been recognised as one of the world's top summer hotspots for the basking shark. Banba's magnificent journey to the Cape Verdes from the waters off Malin head is a valuable piece in the elusive jigsaw of the lifecycle of the sharks. This new finding by may prove to be a significant insight into the underwater world of one of the most endangered and iconic sharks in the Atlantic Ocean. For more information and to see a magnificent video of the shark log on www.baskingshark.ie
Basking sharks have dominated recent sightings of large marine wildlife, according to the Irish Whale and Dolphin Group (IWDG).
The largest shark species in Irish waters accounted for a whopping 43% of sightings submitted to the IWDG's ISCOPE database between 22 April and 1 May.
Other marine species spotted include minke whales (14%), bottlenose dolphins (10%) and sperm whales (2.5%).
April's unseasonably warm weather and calmer seas brought more people out to the water, which may account for this rise in figures.
Ireland's Wildlife has more on the story HERE.
Cork-based boat charter firm Whale of a Time has posted video on its YouTube channel of the Irish Whale and Dolphin Group (IWDG) tagging a basking shark from its boat Mischief:
Apart from whales, basking sharks are the largest species of marine wildlife to frequent Irish waters.