Angel shark Squatina squatina
Irish name: Bráthair
Status
Ireland: Critically endangered. NE Atlantic: Critically endangered. Global: Critically Endangered.
Range, distribution and habitat
This species’ range encompasses the Atlantic coasts of Europe from Ireland and Britain to Morocco, the Canaries, the Mediterranean coasts of Europe, Africa and the Levant, and the Black Sea. Tagging data from Inland Fisheries Ireland show that Tralee Bay is the main centre of its distribution in Ireland, (>90% of total tagged), with Clew Bay a secondary area. This species is known to make extensive migrations southwards from the Tralee Bay area to the Celtic Sea shelf and Bay of Biscay. The species may overwinter in St. George’s Channel. Recent reports of angel sharks have also been received from inner Galway Bay.
Biology and Ecology
A medium bodied shark which has a skate-like appearance. It reaches up to 2.5m TL. It inhabits sandy and muddy bottoms, in shallow depths of 5-100m. Angel shark is live bearing, producing 7-25 embryos. Its gestation period is 10 months and neonates are 20-30cm. Trend Numbers tagged and recaptured since the 1980s, in a tagging programme conducted by anglers working with Inland Fisheries Ireland, show a decline of over 95%. Even in its core area of Tralee Bay, few angel sharks have been encountered in the last 15 years.
Trends in Population
Numbers of angel sharks encountered in tagging programmes conducted by anglers and Inland Fisheries Ireland show a decline of over 90% since the 1980s .
Human impacts
This species is especially vulnerable to coastal fisheries using static nets. In Tralee Bay, one of its main centres, it is particularly vulnerable to static net fisheries targeting crustaceans. It is also an occasional by-catch in mixed trawl fisheries, particularly in St. George’s Channel.
Management/Conservation
It is prohibited to fish for, land or tranship this species under EC fisheries management legislation. This is the highest conservation designation afforded under the Common Fisheries Policy. It is protected in Northern Ireland Inshore Waters out to 6 nautical miles.
Blue Shark Prionace glauca
Irish name: Siorc gorm
Status
Ireland: Near Threatened. NE Atlantic: Near Threatened. Global: Near Threatened.
Range, distribution and habitat
The blue shark has a circumglobal distribution and is common in pelagic oceanic waters throughout the tropical and temperate oceans worldwide. It has one of the widest ranges of all the shark species. It is oceanic and pelagic, found from the surface to about 350m depth. There is considered to be one stock of blue shark in the North Atlantic and this is supported by extensive tagging studies in Ireland and the USA. In the North Atlantic blue sharks migrate northward during the summer and so occur primarily between June and September in Irish waters. Their arrival in Irish waters is often associated with sea surface temperature reaching 15°C. They are most abundant off the south west and west coast and are targeted mainly by charter angling vessels.
Biology and Ecology
The Blue Shark reaches a maximum length of about 380cm. About 50% of males in the Atlantic are sexually mature by 218cm, although some may reach maturity as small as 182cm. Females are sub-adult from 173-221cm and fully mature from 221cm. The length-at-birth is 30-50cm and the average fecundity is 25-50 pups. Life-history information from blue sharks caught in Irish waters is limited. The age range of samples caught in Irish waters indicates that the population occurring north of Biscay is composed mainly of sub-7-year-olds. In Irish coastal waters the sex ratio is skewed towards females, but further offshore it is more balanced.
Trends in Population
Conflicting signals are available from various sources. Catch rates from Irish recreational catches showed a decline over time, and have stabilised at this level in the past decade, but this may not be indicative of the overall stock situation. The latest assessment by ICCAT (2015) suggests that the stock is not over-fished and is above the level that is consistent with maximum sustainable yield.
Human impacts
There are no large-scale directed fisheries for blue sharks but they are a major bycatch of longline and driftnet fisheries for tunas and billfish, where they can comprise up to 70% of the total catches and thereby exceed the actual catch of targeted species. Much of this bycatch is often unrecorded. Since 1998 there has been a Basque artisanal longline fishery targeting blue shark and other pelagic sharks in the Bay of Biscay. Observer data indicated that substantially more sharks are caught as bycatch than reported in catch statistics. It is difficult to accurately quantify landings of blue shark in the North Atlantic, as data can be incomplete, and generic reporting of shark catches has resulted in under-estimation.
Landings data from different sources (ICCAT, FAO and national statistics) vary significantly. Regardless, estimated North Atlantic landings were in the region of 30,000t from 1997 to 2007. Since then estimated landings have increased significantly. Blue sharks are also caught in considerable numbers in recreational fisheries. These fisheries are mainly catch and release in the Northeast Atlantic but in the Northwest Atlantic blue sharks are frequently landed by anglers.
Management/Conservation
There are no measures regulating the catches of blue shark in the North Atlantic.
Porbeagle Lamna nasus
Irish name: Craosaire
Status
Ireland: Critically Endangered NE Atlantic: Critically Endangered. Global: Vulnerable.
Range, distribution and habitat
The porbeagle is a large pelagic, migratory, coastal and oceanic species found in temperate and cold temperate waters worldwide. In the Northeast Atlantic porbeagles occupy a broad distributional range from the Barents Sea to northwest Africa. The Northeast Atlantic population is considered to be a single stock and is managed as such. There are also populations of porbeagles in the northwest Atlantic and in the south Atlantic.
Porbeagles are found on all coasts of Ireland but are more common north of Lough Swilly in Donegal and also off the coasts of Galway, Clare and Cork.
Biology and Ecology
In the Northeast Atlantic stock, it is estimated that males and females do not mature until they are 1.7 and 2.0m fork length, respectively. These lengths correspond to an estimated age-at-maturity of 7-8 years for males and approximately 20 years for females, showing them to be slow growing and late maturing. In Irish waters the majority of rod caught porbeagles are < 2.0m total length and the sex ratio is 1:1.
Porbeagles favour waters between 5-20°C and are among the small number of sharks that can actually maintain a higher body temperature than the water around them. They are recorded in Irish waters between June and October (angling data), where they feed mainly on boney fish such as pollock, whiting, blue whiting, mackerel and also herring.
Trends in Population
Porbeagles are highly vulnerable to fishing mortality and very slow to recover from depletion due to their slow growth rate, low fecundity and late age at maturity. Northeast Atlantic porbeagles have been heavily exploited by commercial longline fisheries since the early 1900s for their high value meat. They have undergone significant declines in abundance due to this exploitation: over 90% decline from baseline in the northeast Atlantic.
Human impacts
Porbeagles were common in the northeast Atlantic and because of this they were fished commercially for most of the 19th and 20th centuries. The main countries involved were Norway, Denmark, Spain and France. Landings of porbeagles peaked in the period of 1933-1939 when 2,000 to 4,000 tonnes were landed by Norway annually. The porbeagle fishery subsequently declined but continued in various countries until 2010 when targeted fishing for porbeagle in EU waters became illegal.
The species continues to be a by-catch in some fisheries, including the international blue whiting trawl fishery, and some bottom trawl fisheries.
Management/Conservation
This species is on the EU CFP Prohibited Species List, and was previously regulated by a TAC, which since 2010 was set at zero TAC. It is subject to a management plan in Canadian waters where it is targeted commercially. In 2012 the North East Atlantic Fisheries Commission (NEAFC) prohibited all directed fishing in international waters. In March 2013 porbeagle was listed on Appendix II of CITES. It is also listed on Appendix II of the Convention on Migratory Species from 2008.
Basking Shark Cetorhinus maximus
Irish name: Liamhán gréine
Status
Ireland: Endangered. NE Atlantic: Endangered. Global: Vulnerable
Range, distribution and habitat
The basking shark is a very large, filter-feeding species that is migratory and widely distributed, but only regularly seen in a few coastal locations and probably never abundant. In the eastern Atlantic, basking sharks are distributed from Iceland, Norway and as far north as the Russian White Sea (southern Barents Sea), south to the Mediterranean and occasionally as far south as Senegal. A single population is believed to exist in the Northeast Atlantic although there is one report of an east-west trans-Atlantic migration.
Trans-equatorial migrations and migrations into tropical areas and mesopelagic depths are also reported in the North Atlantic, including autumn southward movements to areas off North Africa (Madeira) for overwintering. Migration and levels of mixing between populations have yet to be fully determined. An active research and conservation interest in this species in recent years has led to an increase in the number of sightings reported around Ireland. In Irish waters basking sharks are most commonly observed off the coasts of Donegal, Mayo, Cork and Kerry.
Biology and Ecology
Little is known about the biology of this species. The reproductive biology is considered to be similar to that of other lamnoid sharks. Pairing takes place in early summer following courtship behaviour, with wounds caused by copulation having been recorded in British waters in May by Matthews (1950). A single functional ovary contains a very large number of small eggs. Estimates for gestation period range from 12-36 months. The smallest free-swimming individuals recorded are about 1.7-1.8m. However, the young are very rarely encountered until they reach more than 3 m in length. Males become sexually mature at a length of 5-7m and females at 8.1-9.8m.
Basking sharks are plankton feeders and are often associated with high levels of chlorophyll and surface aggregations of zooplankton, particularly along tidal and shelf-break fronts. They are most often observed when feeding in surface waters by swimming open-mouthed and continuously filtering the water.
Trends in Population
Basking sharks have a long history of exploitation, particularly in the Northeast Atlantic. Annual catches by former directed fisheries in Norway, Ireland and Scotland fell by approximately 90% during a period approximating half a generation. The species is susceptible to exploitation due to its large size and aggregating behaviour. Although the fishery has ceased, population recovery in basking sharks can be very slow due to low productivity and late age at maturity.
Human impacts
In Irish waters there were three main fisheries for basking waters; the 18th to 19th Century Sunfish Bank fishery, the mid-20th Century Achill Island fishery, and the modern Norwegian fishery. Records suggest that the initial fishery was active for several decades between 1770 and 1830, with at least 1,000 sharks caught per year. In the early 1830s, sharks became very scarce and the fishery collapsed in the second half of the 19th Century. This scarcity of sharks lasted for several decades. In the middle of the 20th Century a new fishery began at Achill Island, where between 1,000 and 1,800 sharks were taken each year from 1951 to 1955. Thereafter annual catches dropped to around 480 in 1956 -1960, around 100 in 1961-65, and then about 50-60 for the remaining years of the fishery.
Basking shark was also targeted by Norwegian harpoon vessels in the Celtic Seas until comparatively recently. Today the species is an occasional by-catch in demersal trawl fisheries and entanglement in static fishing gear. They are also susceptible to collisions with vessels.
Management/Conservation
This species is on the EU CFP Prohibited Species List. It is also protected in Northern Ireland, (since 2011) and on the high seas of the Northeast Atlantic and the Mediterranean (2012, through NEAFC). It is listed on Appendices I and II of the Convention on Migratory Species, and on Appendix II of CITES.
Undulate Ray Raja undulata
Irish name: Roc dústríoctha
Status
Ireland: Endangered. NE Atlantic: Near Threatened. Global: Endangered.
Range, distribution and habitat
The undulate skate is a medium-sized, inshore skate that has a patchy distribution in the northeast and eastern central Atlantic, with discrete areas where it may be locally common (southwestern Ireland, eastern English Channel, southern Portugal). It also occurs in the Mediterranean Sea, where it appears to be rare. The Undulate Skate occurs in shelf waters down to about 200 m depth, although it is more common in shallow waters. In Irish waters the undulate skate distribution is centred on Tralee Bay with records southward to Mizen Head and northward to the Aran Islands. Over 99% of all undulate skate tagged in Ireland (1972-2014) were from Tralee Bay. The population in Ireland is isolated from other populations in the Atlantic.
Biology and Ecology
In the neighbouring Normano-Breton Gulf stock which is comparable in characteristics, the length-at maturity has been preliminarily estimated as 78cm and 82cm for males and females, respectively. The observed length range was from 18–99cm for males and 18-103cm for females. Combined data from the North Sea and Celtic Sea eco regions indicate a length-at-first maturity of 80cm and 79cm for males and females respectively, and a length-at-maturity of 83cm for males. The observed length range was 22–89cm and 17–60cm for males and females, respectively. Throughout the species’ range neonates, juveniles and egg-laying females have been observed in estuarine and lagoon habitats.
Trends in Population
An index of fish tagged and recaptured by Inland Fisheries Ireland shows a decline of 60-80% since 1981. However, the trend since 2006 may be confounded due to reduced angling effort arising from a reduction in the size of the local angling charter fleet.
Human impacts
As a coastal and inner shelf species it is susceptible to bycatch of trawl and gill net fisheries. It is particularly vulnerable to static net fisheries, targeting shell fish, in its core range in Tralee Bay. The majority of tagged undulate skate recaptures from 1970 to 2014 was due to recreational angling (operating on a catch and release basis), but at least 28% were attributed to commercial fishing.
Management/Conservation
This species is managed as an exception to the generic skate and ray total allowable catch (TAC) under the EU CFP. It must not be be targeted, when accidentally caught, it must not be harmed but released immediately.
Long nosed skate Dipturus oxyrinchus
Irish name: Sciata socfhada
Status
Ireland: Vulnerable. NE Atlantic: Near Threatened. Global: Near Threatened.
Range, distribution and habitat
Long nosed skate is endemic to the Northeast Atlantic and Mediterranean, though the populations in each area are known to be genetically distinct. It occurs in the Atlantic from southern Norway, the Shetlands, Faroe Islands and Rockall Bank south to the Canaries. Its range extends round the entire Mediterranean margin, and it is a demersal species occurring in a wide range of depths from 90-900m. It is unclear if the skates on the Rockall Bank and those previously recorded from Irish shelf waters are from the same population, though there are no natural barriers for a deep-sea species like this.
Biology and Ecology
The biology of this large bodied skate is poorly known. It is egg laying with the spawning season stretching from spring to early summer. It reaches up to 150cm. Length at maturity is estimated as 83cm for males and 104cm for females. Both sexes are estimated to reach sexual maturity from 6-8 years. The estimated longevity off Tunisia is 26 and 38 years for males and females, respectively.
Trends in Population
Between the late 1960s and 2002 UK ground fish surveys very occasionally reported this species in very low numbers in the Celtic Sea and off southwest Ireland at depths of 111−159m. There have been no recent reports from those surveys, and only 6 records from the Irish Groundfish Survey (begun 2003) with none since 2008. It is known to occur in small but stable numbers on the Rockall Bank (UK-Scotland surveys) and in Norwegian and Biscayan waters. be mis-classified. Extra attention is required to obtain a better classification of this species by the time of the next Red List process.
Human impacts
Because of its wide depth range it is vulnerable as a by-catch in almost all mixed demersal fisheries, including deepwater fisheries on the slopes of the continental shelf and the Rockall Bank.
Management/Conservation
There are no management or conservation measures in place for this species.
White skate Rostroraja alba
Irish name: Sciata bán
Status
Ireland: Critically endangered. NE Atlantic: Critically Endangered. Global: Endangered
Range, distribution and habitat
It ranges, in the Atlantic, from western Ireland to South Africa, extending through the western Mediterranean to Tunisia and western Greece. It also occurs in the southwest Indian Ocean. It occurs on sandy bottoms in coastal waters to the upper slope region between about 40 to 400 m and exceptionally down to 500m. In Ireland the species is confined to the Tralee Bay region and to a lesser extent, Galway Bay and these are the only known refuges for the species in the north east Atlantic.
Biology and Ecology
This is a large bodied, slow growing and late maturing species. Maximum recorded size is 200cm. Estimates of total length at maturity varied between two studies from North Africa: 130cm (males) and 120cm (females) and 119cm for males, and 129cm for females. These authors report age at maturity as 20 and 23 years, for males and females, and the oldest male reported in that study was 32 years, whereas the oldest female was 35 years. The longevity was estimated at 51 and 76 years for males and females, respectively. A captive white skate at the Galway Cartilaginous Fish Red List 2016 36 aquarium laid an egg at the age of 7, though this may not be indicative of conditions in the wild. Gestation period may be about 15 months and females produce between 55 and 156 ova per year, with 1-2 egg capsules reported to be contained in each female’s oviducts at a time.
Trends in Population
No information is available.
Human impacts
This species is especially vulnerable to coastal fisheries using static nets. In Tralee Bay, one of its known refuges, it is particularly vulnerable to static net fisheries targeting crustaceans.
Management/Conservation
It is prohibited to fish for, land or tranship this species under EC fisheries management legislation. This is the highest conservation designation afforded under the Common Fisheries Policy.
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Angel Sharks 