Sharks in Ireland - 36 different kinds of sharks in Ireland!
Basking Shark, Dingle Bay, Ireland SW
Basking Shark south of Blasket Islands, West Kerry, Ireland.
Achill Island Shark Fisherman reminiscences
Some shark facts about Irish sharks, Basking shark evolutionary profile, 36 different kinds of sharks in Ireland, History of shark fishery in Ireland
Most sources cite the presence of 35 different species of shark in Irish waters from oceanic and pelagic to coastal and offshore and beyond the continental shelf edge into the abyssal plain, but none of the sources mention the presence of one (unspecified) species of the hammerhead shark family as recorded by a fisherman friend of the author who caught one a few years ago in his nets off the West Kerry coast. This may or may not have been a smooth hammerhead shark but was definitely a member of the unmistakable hammerhead shark family. Observers on the Marine Institute research vessel R.V. "Celtic Explorer" also observed what they thought may have been the fin of a hammerhead shark near the continental shelf edge on an exploratory trip in 2019 and this, in combination with the previous, actual landed specimen, as above, should confirm the presence of hammerhead shark in Irish waters. [Please contact the author below for more details of the hammerhead landing]
This brings the official number of sharks recorded in Irish waters from 35 to 36 different species, including the new to Irish waters - hammerhead shark - caught by my friend in his nets.
Many of these sharks will only ever be seen by offshore fishermen in nets or trawls or by research vessels using ROVs [Remote Operated Vehicles] or observers from the ship's bridge. So far, no Great white sharks have been observed in Irish waters but there have been some reported sightings from Cornwall in SW England. There are some Great white sharks in the Mediterranean and with climate change and the Atlantic warming slowly from the south, as evidenced by cod moving further north and hake replacing them, it is only a matter of time before there are some sighted in Ireland, probably off the SW coast of Ireland first and then more than likely continuing northwards along the west coast predating on the abundant stocks of grey seals along the west coast of Ireland.
Particulars of these shark** can be found in "Ireland Red List No. 11 - Cartilaginous Fish (sharks, skates, rays and chimaeras)" National Parks and Wildlife Service. Clarke, M., Farrell, E.D., Roche, W., Murray, T.E., Foster, S. and Marnell, F. (2016)
Among the 71 species of cartilaginous fish recorded in Ireland 58 species are assessed including 35 species of shark (all of the recorded number). There are 6 cartilaginous fish (10%) in the List assessed as "Critically endangered" including 3 sharks - the Portuguese dogfish, the Porbeagle shark and the angel shark. The Portuguese dogfish is an offshore species with very low survival rates even as a discard and does not survive being brought to the surface quickly from the deep water fishery from which it is taken. The Porbeagle shark was once common around the Irish coast but was overfished since the 1900s almost to extinction, by long-lining mainly and targeted due to its high-value flesh. Ireland is one of the last remaining refuges for angel shark in NW Europe, and Tralee Bay, Co. Kerry in particular, possibly because ground trawling is not allowed because of the presence of the native oyster beds which are protected by the local population of fishermen in Fenit and the Maharees.
3 more species of shark plus 2 skate (9%) were assessed as "Endangered" including the leaf-scale gulper shark, the Basking shark and the spur-dog, which was also plentiful until recently, especially off the Clare coast and the mouth of the Shannon but was overfished and exported to England as "rock salmon". Anecdotal evidence seems to indicate that they are now making a recovery.
Basking shark was almost fished to extinction, by nets and harpoon, a couple of times but the population is slowly making a recovery as it is now a prohibited fishing species since 2007 and a protected species under the Irish Wildlife Act and Amendments since 2021. They have a late sexual maturity age [ males at 5 - 7m length; females at 8.1 - 8.8m length (Compagno 1984)] and only about 6 - 7 pups every 3 -4 years. Little is known about the biology of Basking shark and sources quote the gestation period as anything between 12 - 36 months (!?) with the Basking shark giving birth to live young every 3 - 4 yrs. and living to approx. 50 yrs.
New born Basking shark are approx. 1.7 - 1.8m in length when born (Parker & Stott 1965; Sim et al 1997) and the Blasket Islands area may be a basking shark nursery area as on August 30th, 2020 the dolphin and whale watching tour boat M. V. "Blasket Princess" had a young Basking shark approx. 2.1 - 2.3m beside the vessel and this specimen was also viewed subsequently by other following marine boat tour operators from Dingle. Over the years we have had numerous sightings of very immature basking shark just over 2 meters long and especially off Gob an Oileáin and the Trá Bán (White Strand) beach of the Great Blasket island.
These various specimens may have just been born earlier in the season, possibly around April / May period when the mature females are present.
3 More species of shark plus 2 species of skates and rays (10%) are assessed as "Vulnerable" in the red List including the long-nosed velvet dogfish, the kitefin shark and tope.
Yet, despite all the interesting shark, ray and skate information found in the "Ireland Red List No. 11 - Cartilaginous Fish" there is no mention of the hammerhead shark caught in the nets of my fisherman friend's nets off the Kerry coast a few years ago.
Including this unknown, but possibly smooth hammerhead species, from the hammerhead family of sharks, we have 36 species of sharks frequenting Irish waters.
Brief Evolutionary Profile of Basking Sharks
Sharks are long-lived evolutionary survivors! In the evolutionary race, humans and mammals in general, are only a flash in the pan compared to the evolutionary lifespan of Sharks! The common ancestor of various shark species evolved about 450 million years ago just before the beginning of the Carboniferous Period when many other fish species died out (approx. 85% of all species died out in a mass extinction event) and many different species of shark evolved to fill out the various niches left vacant. Primitive mammals on the other hand first started to evolve about 178 million years ago from a reptilian ancestor, as is evident from recent paleontological evidence mainly from China.
There was a second extinction event 374 million years ago during the Devonian Period which wiped out 75% of all animals, but sharks survived.
During the middle of the Permian Period, 250 million years ago there was another mass extinction event of 95 - 99% of all marine animals and fish, referred to as the Great Dying Event, but some sharks survived this mass extinction including the common ancestor of the present-day sharks.
Sharks also survived the mass extinction event in the Triassic period when 80% of species died out and the last and 5th extinction event which wiped out the dinosaurs and 78% of other species, 66 million years ago.
The Elasmobranch subclass of sharks was a highly adaptable species the has basically survived five mass extinction events of other species over 450 million years. The present evolutionary stage of the basking shark with gill rakers for scooping up zooplankton and tiny hook-like teeth evolved about 45 million years ago. Basking shark and the Great white shark had a common ancestor but obviously evolved in different ways. [Just look at their teeth but not too closely!].
The earliest Lamniformes order of sharks (mackerel sharks),evolved about 65 million years ago, just one million years after the event that caused the mass extinction of the dinosaurs. At the same time as these common ancestors of the basking shark and the Great white shark were swimming around the world's oceans, the common ancestor of mammals was lurking around in the undergrowth as a nocturnal, shrew-like creature about the same size as a dog. Eventually, over evolutionary time, Hominins evolved into Home sapiens about 300,000 years ago and given that the average lifespan for a mammalian species from origination to extinction is about one million years on average (up to 10 million years exceptionally) we still have about 700,000 years to wipe out all the other species on the planet.
However, given that Homo sapiens is such an errant, self-destructive, flash-in-the-pan type of species it is doubtful that the species will last that long and will probably morph before then into a hybrid sort of A.I. assisted pseudo-mammal with many bodily functions farmed out to non hybridised "primitives" and mammals.
Perhaps the Greenland shark who lives at the bottom of the Arctic ocean patiently waiting for whalefall and organic marine "snow" falling from the surface, and can live from 250 - 500 years is lurking in the depths waiting to emerge and further evolve after the next mass extinction. Our pre-mammalian, reptilian ancestors were not that much prettier than him! The age of the oldest Greenland shark scientifically assessed to date is calculated at 392 yrs. ( ± 100 yrs.)
Hopefully with all these amazing shark facts we can learn to respect and protect our sharks in the same way as we do with our cetaceans (whales, dolphins and porpoises) as they are all equally necessary for a healthy marine ecosystem.
Short History of Basking Shark Fishery in Ireland
The Basking shark is a large placid animal of maximum length 10m (33ft.) and maximum weight 5 tons (5,000 kgs.).The liver of the basking shark is roughly about 25% of the animal's body weight and is rich in oil (squalene). When rendered down the liver of a 5-ton shark delivers about 4 - 5 barrels (180gals,) of shark oil. This was mainly what sharks were hunted for as it was cheaper than the spermaceti whale oil. later, when demand for the oil lessened because of the use of artificial mineral oil, they were hunted for their fins for making shark fin soup which is regarded as a delicacy in the Far East, especially at weddings. The author of this blog actually saw a whole street of shark fin soup restaurants in the Chinatown part of Bangkok. Market wholesale prices for an individual shark were reported to be as high as $2,4000 in 2004 (Sims et al, 2005).
The Norwegians were the main fishers for basking shark from the mid-1700s (1770) and when their own stocks were depleted, they fished them off the coasts of Scotland and Ireland until the mid-1800s (1830) when stocks became depleted there also. This fishery was known as the "Sunfish Bank Fishery" and various locations are given for this bank which may be about 30 miles west of Westport harbour and just inside the 100m depth contour, with seamounts rising to depths of about 40m where basking shark are said to have congregated. This fishery averaged about 1,000 basking sharks per season until the fishery collapsed..
The fishery resumed after the great war and the peak of this fishery was between 1959 - 1980 often averaging 4,000 sharks killed in a so-called "good year" (5,266 Basking shark killed in 1979 - page 214, ICES WGEF Report 2017)
These Norwegian boats fished for shark off the Irish coast until 1998 when they became a prohibited species for commercial fishing under EU Fisheries Regulations and EU vessels must release live shark and discard dead shark. Norwegian vessels on the other hand are still allowed to land dead specimens!!!
In Ireland there was a whale and shark fishery set up in Donegal Bay in 1759 where the swivel gun method of harpooning was used for the first time. [McGonigle, 2008].
Perhaps the best-known fishery was the Achill Island Fishery which was conveniently located close to the Sunfish Bank above. This was a drag net fishery with one end of the net attached to the shore in Keem Bay, Achill Island, Co. Mayo and the fish became entangled in the nets. The fishery ran from the beginning of April to mid-May or from April 15th to May 15th, according to some sources. This is the period when the fish apparently came inshore from and went out towards the Sunfish Bank, possibly as some part of a mating ritual. In recent years something similar was observed about 30 miles off the coast of Clare with many large Basking shark swimming in circles and spirals.
Here are some of the recorded stats. from the fishery:
1951 - 1955 [ 1,000 to 1,800 basking shark per season]
1956 - 1960 [ 480 basking shark per season]
1961 - 1865 [ 100 basking shark per season]
1965 - 1984 [ 50 60 basking shark per season]
(Cartilaginous Fish Red List 2016)
In the last year of the fishery (1984) a total of 5 basking shark were landed in Achill, the last one landed was for a T.V. documentary produced by ITV and Channel 4 entitled "The Shark hunters of Achill Island" which was produced 50 years after the original and iconic "Man of Aran" (1934) by Robert J. Flaherty about (fictional) shark fishermen on the Aran Islands.
After 1984, basking shark were again almost totally wiped out by a long period of coastal drift netting for salmon off the entire west coast of Ireland and sharks became entangled in the gear and that section of the net was cut out and the entangled sharks were left to drown. For years there were no Basking shark to be seen and it seemed (to me0 a sad end for such a noble and placid creature, but then drift netting was banned and gradually Basking shark reappeared to herald in the summer and fine weather again.
They were nominated for protection under the Irish Wildlife Act and Amendments in 2021 and we have the pleasure of their company again for about 6 weeks from the beginning of April to mid-May before they go further north towards Donegal and Scotland and then out into the deep again, either south towards the Madeira islands and the north west coast of Africa or west towards the continental shelf and the edge of the Gulf Stream where they continue to pursue zooplankton in their diurnal migrations to the surface, scooping them up in their open one meter wide gape.
Join us on one of our marine tours from Ventry Harbour during April or May for a good chance to see one of our most long-evolved megafauna and one of the planet's great survivors - the Basking Shark (Cetorhinus maximus) Irish name(s) - Liamhán gréine; Ainmhí sheoil. Common name: Sunfish*
* The common name, not to be confused with Mola mola, the true Sunfish (or Moonfish)
Log of the Whale Watching Tour boat M.V. "Blasket Princess"
Captain Whales Galore 18.02.2022
** 36 Sharks of Ireland
Oceanic and Pelagic Species (5); Basking shark; Porbeagle shark; Tope; Blue shark; Smooth hammerhead shark
Continental Shelf & Coastal Species (5): Angel shark; Spur-dog: Bull huss; Starry smooth hound; Lesser-spotted dogfish.
Deep-water Species (26): sharp-nose seven-gill shark; Blunt-nose six-gill shark; Frilled shark; Short-fin mako shark; Common thresher shark; White ghost shark; Iceland catshark; Ghost shark; small-eye catshark; Black rough-scale catshark; Black-mouth dogfish; Mouse catshark; False catshark; leaf-scale gulper shark; Bird-beak dogfish; Kite-fin shark; Bramble shark; Greater lantern shark; Velvet belly shark; Black dogfish; Portuguese dogfish; Longnose velvet dogfish; Knife-tooth dogfish; Little sleeper shark; Sharp-back shark; Little gulper shark.