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Dangerous sharks in Ireland?

2

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  • Registered Users Posts: 92 ✭✭papachango


    Kess73 wrote: »
    You could have become the Irish version of Rodney Fox. :)

    Although he was spearfishing when hit.

    Well whatever it was, thankfully at least, it wasn't starving! It can be unnerving at times but the experience of being out at sea with just your wits, whether surfing or spear fishing, is well worth the experience.
    I have enjoyed the attentions of a shark whilst spearfishing in Australia in the 90's, Thankfully it was not a man eater and was just curious. About 6.5 feet long, quite lazily made a beeline for me. It was a wobbegong I think. I saw it swim up from a depth of about forty feet down. kept the gun pointed at him though just in case he got frisky!! He came to within three feet and just hovered there on the current for about 40 seconds before heading back. very nosey!!
    Its tricky spearfishing in Australia I had a one kill then exit policy. Dont understand people who string speared fish to themselves and carry on spearfishing when there could be a tiger or GW about.
    My experience in donegal could have been a Porbeagle, but would it not have had to be an unusually large one to hit 15 feet in size. either way it made my heart skip more than a beat or two, and we all calmly decided to catch the next wave in and called it a day!


  • Closed Accounts Posts: 13,993 ✭✭✭✭recedite


    Kess73 wrote: »
    As stated earlier in this thread, Atlantic Great Whites are not known to predate on seals to any great degree, they specilize on fish prey, with the deep swimming six gill shark being one of their main prey species. So why would they be seen near the surface or near the shore?

    The Orca pods around Ireland and Britain have long been known to be mainly fish hunters also, so why would they follow the totally different behavioural traits of Orca that prey primarily on marine mammals.

    .
    I actually meant that if we know about transient dolphins then we should also know about transient orcas, not that the orcas would eat the dolphins. However I'm more curious about this phenomenon of a fixed ecotype, whereby the behaviour of the species is completely different in the Pacific. Is it a cultural thing or is there some genetic component? If you transported a GW or orca from an area where it was accustomed to eating harbour seals and released it in our waters, would it continue to do so? I suspect that any individuals making the long trip across the Atlantic would have got out of the habit and would have got used to feeding on the sharks.Behaviors can be re learned though.


  • Registered Users Posts: 92 ✭✭papachango


    recedite wrote: »
    Basking shark?

    No, I am very familiar with these sharks. BTW saw one at Slea head in Kerry this year, HUGE! Dorsal fin like a car door!


  • Closed Accounts Posts: 13,993 ✭✭✭✭recedite


    papachango wrote: »
    Well whatever it was, thankfully at least, it wasn't starving! It can be unnerving at times but the experience of being out at sea with just your wits, whether surfing or spear fishing, is well worth the experience.
    I have done some kayak surfing up there at Tullan, Donegal and I would not be happy about any large beast lurking below me! I'll even admit to once being scared out of the water while snorkelling in Sligo by a large grey seal that was "stalking" me.(In a paparazzi way, not in a predatory way)


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    recedite wrote: »
    I actually meant that if we know about transient dolphins then we should also know about transient orcas, not that the orcas would eat the dolphins. However I'm more curious about this phenomenon of a fixed ecotype, whereby the behaviour of the species is completely different in the Pacific. Is it a cultural thing or is there some genetic component? If you transported a GW or orca from an area where it was accustomed to eating harbour seals and released it in our waters, would it continue to do so? I suspect that any individuals making the long trip across the Atlantic would have got out of the habit and would have got used to feeding on the sharks.Behaviors can be re learned though.



    There is a line of thought that many marine biologists suscribe to that there is actually a genetic difference between the Great whites of different parts of the world that makes up their feeding profile and habits.

    DNA samplings has shown genetic variations in sharks from africa and those from Australia, and when testing was done on Great whites in colder waters there were even more DNA variations.

    The line of thought is that GWs from certain breeding grounds come hardwired (for lack of a better term) with a specific prey type imprinted on them from birth, so that they are primarily a fish eater or primarily a meat eater as in pinnipeds.

    It is very early days in this line of study though in terms of results.

    Your Orca idea is an interesting one, my best guess is the transported Orca would try to seek out it's normal food type and would continue to do so until extreme hunger forced it to try another food source.

    But that it would return to it normal preferred food type as soon as it became available.

    The fish eating Orcas (residents)have been studied quite a bit and have shown that they have developed hunting skills that just don't work as well on pinnipeds, and the pinniped eating Orca (Transients) have been found to not eat fish.

    The fish eating Orca are always far more social and have a more complicated language, whereas the Transients are far less social and have a much simpler language.

    They also won't mix with each other when together in one area, nor will they feed together. Like the DNA variations on the Great Whites, it is thought that Orca may be made up of a number of similar but different sub species.

    There is still loads to be discovered about them though as many Orca in many parts of the world, like Ireland, have had minimal studies done on them and their habits. We don't actually know for sure what the Irish Orca would fall under in terms of being transient or resident or even off shore, so a lot of it would be best guesses based on studies done in waters that have similarities in terms of water temp and available prey species. The size and shapes of the orca would also give clues as to what type they are.


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  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Even going back tens of thousands of years, ocean conveyer belts, ice ages etc have modified conditions, timescales are small in this context, depending which scientific paper you read eevn as small as 40 - 60 years for a significant change to affect a species distribution.

    Could Great Whites' ranges be becoming amplified? Sure! Could we come close to proving this? Not likely just yet! We know next to nothing about distribution ranges for species such as these, even if they turned up in bycatch, this is incidental and science likes far harder data figures.

    Leading nicely on from this, to answer your question Kess, I was working in Galápagos off Ecuador, assisting tagging of hammerhead, galápagos and whale sharks in efforts to know more about their ranges to assist protection measures in the future. It is only recently we have some definites about their range in the +1000km context. It is common and easy to dive and snorkel, uncaged with hundreds of hammerhead, whitetip and galápagos sharks there.
    :)


    http://irishmarinelife.com





    Now that sounds amazing. I have freeswam with smaller species of shark, but never with any of the larger species, or at least not to my knowledge :). It must be a great experience. Seeing a great white up close from a cage is breathtaking and it conveys such a majestic feeling so I cannot imagine what it must feel like without that cage.

    What type of tagging were you involved in? Was it the standard labelling tagging or satellite tagging? I got to listen to a lecture by Dr. Peter Klimley a few years ago about the acoustic tagging that he does and how the cage diving of of Guadalupe Island helps fund the Great white research programs in Mexico.

    Sounds like you were involved in some fascinating and very worthwhile projects.


  • Closed Accounts Posts: 13,993 ✭✭✭✭recedite


    Kess73 wrote: »
    The fish eating Orca are always far more social and have a more complicated language, whereas the Transients are far less social and have a much simpler language.

    They also won't mix with each other when together in one area, nor will they feed together. Like the DNA variations on the Great Whites, it is thought that Orca may be made up of a number of similar but different sub species.
    It reminds me of H.G.Well's "The Time Machine" where as it turned out they were right to view the other group suspiciously. For a new species to develop, a separation of populations is necessary, and this can occur either geographically or through behavior. It seems this process could be well underway.
    Keiko the moviestar whale from "Free Willy" was released off Denmark a few years ago, but was unable to reintegrate and died soon afterwards.


  • Registered Users Posts: 4,632 ✭✭✭NoQuarter



    Leading nicely on from this, to answer your question Kess, I was working in Galápagos off Ecuador, assisting tagging of hammerhead, galápagos and whale sharks in efforts to know more about their ranges to assist protection measures in the future. It is only recently we have some definites about their range in the +1000km context. It is common and easy to dive and snorkel, uncaged with hundreds of hammerhead, whitetip and galápagos sharks there.
    :)

    Sorry to bump an old thread but i happened across it while searching for info on the galapagos! Irishmarinelife could you tell us a little bit more on what you were doing over there and how you came to be in that position? I must admit im very jealous!
    Kess73 wrote: »

    Have you gone diving with GWs around? If so, I would love to hear about your experiences and if I may, could I ask where you did so?

    Ive had the extreme pleasure of diving with GW's off gansbaai to the east of cape town, they hunt the seals on a tiny island about 1 kilometer off the shore, amazing sight really! It reminded me of a scene in jaws i watched as a child where the GW came straight at the window of the underwater lab thing! It was just like that, out of the murky water this huge fish just effortlessly glided toward the cage, and swam past, its eyes are so striking, HUGE and deep black!

    Another thing i found strange was that they moved with the current, hard to explain but not something you can see on the TV, they kind of drift side to side, quite and exrtaordinary sight! Also while i was out of the cage i was standing at the side of the boat and right beside the boat an enormous (16+ foot) shark glided past at an angle so its eye was looking up out of the water, it was so close i could have (foolishly) leaned over the side and touched it as it swam by! All in all we probably seen about 7/8 different sharks that day, 3 at a time sometimes!

    On topic with the thread, I certainly believe there have been a few nomadic GW's passing through at some stage, I think as regards of why there is no residency is a food source issue as opposed to a temperature issue as I can vouch that the water i dived in in South Africa (in autumn) was FREEZING! just as cold as any water ive swam in up here, after all it is still the atlantic ocean.


  • Registered Users Posts: 4,319 ✭✭✭Half-cocked


    Kess73 wrote: »
    I don't think we have resident great whites in our waters, but I do think that we have transient great whites who pass in and out of the Irish waters on that map...... but until, like you have said, one gets caught and officially reported in our waters, then there is no definitive proof of them there.

    We have plenty of other fish species that migrate into our waters during the Summer months (mackeral, tuna etc), so it would seem reasonable that GW's might appear too? Especialy if they are preying on these other migratory species. As for catching one, there is a lot of blue shark angling off the South and West coasts during the Summer months with chum used to attract the fish, so if GW's are around you would think an angler would have hooked one by now - unless the baits being used are not attractive to GW's. But even so, there would have been sightings of fish following a chum trail. As you state, I'd want to see one caught or positively ID'd before I was satisfied they are in our waters.


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Couldn't a Killer Whale have done this? There are quite alot around W and NW Ireland apparantly.

    I read on the BBC website http://news.bbc.co.uk/earth/hi/earth_news/newsid_8440000/8440002.stm that there are two types of Killer whales in UK (I think we can say Ireland too here).

    "Type 2, on the other hand, is a specialist feeder that scientists suspect exclusively feeds on marine mammals such as small dolphins and whales"





    I think at the time they had discounted the idea of it being a Killer whale due to the bite radius and the shape of the bites not matching that of an Orca attack.


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  • Closed Accounts Posts: 18 fabhcungorm


    Kess73 wrote: »

    The Orca pods around Ireland and Britain have long been known to be mainly fish hunters also, so why would they follow the totally different behavioural traits of Orca that prey primarily on marine mammals.


    Plus they are not preyed upon by the Orca in Irish waters and have often been seen swimming together. Fish eating Orca do not pose a threat to Dolphin unless the Orca is literally starving.

    I read on the BBC website http://news.bbc.co.uk/earth/hi/earth...00/8440002.stm that there are two types of Killer whales in UK (I think we can say Ireland too here).

    "Type 2, on the other hand, is a specialist feeder that scientists suspect exclusively feeds on marine mammals such as small dolphins and whales"


  • Closed Accounts Posts: 18 fabhcungorm


    fast reply :) , never mind my last post ;p


  • Registered Users Posts: 5,856 ✭✭✭Valmont


    fryup wrote: »
    are Porbeagle dangerous to humans?
    They are dangerous to fishing lines, I can tell you that much! I have caught a couple of tope shark over the years and for two years we encountered some incredibly strong sharks that snapped our tope lines every time. My best guess is that it was a porbeagle.


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Valmont wrote: »
    They are dangerous to fishing lines, I can tell you that much! I have caught a couple of tope shark over the years and for two years we encountered some incredibly strong sharks that snapped our tope lines every time. My best guess is that it was a porbeagle.



    Yeah it is possible that a porbeagle came in for a free lunch, but I would lean towards it being a blue shark. We get some really big ones off of the Clare coast.

    Have lost quite a few tope and dogfish down the years, and they seem to be mostly taken by blues in my case.

    I think I read somewhere that porbeagle will rarely eat tope, dogfish or other small sharks, but the sight of a hooked tope must paint a very tempting picture for a prowling porbeagle.


  • Registered Users Posts: 562 ✭✭✭lcrcboy


    Orcas off the Irish coast link to story:

    https://selvavidasinfronteras.wordpress.com/2011/07/15/100-killer-whales-off-ireland-and-scotland/


    story about great whites potentially being in British waters from the BBC:

    http://www.bbc.co.uk/news/uk-england-14657123


  • Registered Users Posts: 108 ✭✭Gunnerkid


    lcrcboy wrote: »
    Orcas off the Irish coast link to story:

    https://selvavidasinfronteras.wordpress.com/2011/07/15/100-killer-whales-off-ireland-and-scotland/


    story about great whites potentially being in British waters from the BBC:

    http://www.bbc.co.uk/news/uk-england-14657123

    cool... dragging up an old thread here but here is a video of a porbeagle being caught off Cornwall and its big



  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    That's a nice looking fish. Think the guy is being more than a tad optimistic to suggest that she (at that size it is more likely the fish is a she) is around the 600lb mark though. She is big, but looks closer to the late 300's or early 400's mark than the late 500's/early 600's.


    We have a decent population of porbeagle in and around Irish waters though. Have seen some lovely specimens over the years when diving in Irish waters.


  • Closed Accounts Posts: 9,700 ✭✭✭tricky D


    http://www.bbc.co.uk/news/uk-wales-19182452

    Blue shark spotted at New Quay, Wales. Nice footage of it 2 yards from shore.


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Unusual behaviour for a blue. Smacks of a sick fish.


  • Registered Users Posts: 108 ✭✭Gunnerkid


    http://news.sky.com/story/972970/show-off-thresher-sharks-welsh-acrobatics

    Sky news story on a Thresher Shark leaping out of the water seen by passengers on a dolphin spotters boat. Apparently it was spotted closer to the coastline then this species natural deep water habitat, possibly due to recent warmer waters


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  • Registered Users Posts: 1 unbirthdayboy


    I guess while food is abundant here it's even more so elsewhere. Maybe the Great Whites are just picky


  • Registered Users Posts: 3,878 ✭✭✭whyulittle


    A tagged Great White is making its way across the Atlantic.

    http://www.bbc.com/news/science-environment-26467037


  • Registered Users Posts: 9,204 ✭✭✭dodderangler




  • Registered Users Posts: 9,603 ✭✭✭Birdnuts


    whyulittle wrote: »
    A tagged Great White is making its way across the Atlantic.

    http://www.bbc.com/news/science-environment-26467037

    I feel some music is missing from that link!! - let hope the Daily Mail doesn't get hold of this with the usual measured headlines...not!!


  • Registered Users Posts: 3,704 ✭✭✭Joeseph Balls


    Birdnuts wrote: »
    I feel some music is missing from that link!! - let hope the Daily Mail doesn't get hold of this with the usual measured headlines...not!!

    They did unfortunately. The kitchen warrior read it to me from a link on facebook yesterday. Think 'were on red alert as killer shark makes its way to our shores':rolleyes::rolleyes::rolleyes:

    Oh and just 'days away'.


  • Registered Users Posts: 9,204 ✭✭✭dodderangler


    She must be coming up for paddys day


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    She has continued to cross the Atlantic. She passed over the mid-Atlantic ridge yesterday.


  • Registered Users Posts: 3,704 ✭✭✭Joeseph Balls


    Kess73 wrote: »
    She has continued to cross the Atlantic. She passed over the mid-Atlantic ridge yesterday.

    Due to arrive by the end of the week. She a big girl. Is there a website where you can track her movements?


  • Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Due to arrive by the end of the week. She a big girl. Is there a website where you can track her movements?




    http://www.ocearch.org/



    https://www.facebook.com/OCEARCH


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  • Registered Users Posts: 6,551 Mod ✭✭✭✭SeaFields


    Porbeagle Washes up in Kerry

    With all this news of Lydia, our common sharks are still around. A seemingly healthy female porbeagle washed up in kerry. Great photo in the article.

    Some tabloids refering to it as a great white tho in typical hysterical fashion.


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