M. Pawson and M. Vince
The Centre for Environment, Fisheries and Aquaculture Science (CEFAS)
Pakefield Road, Lowestoft, Suffolk NR 33 OHT UK, England
The elasmobranchs (fish of the Order Selachii, or chondrichthyans) first appeared around 400 million years ago, and the 25 extant families are well represented in fossil remains. For the purpose of distinguishing and characterising commercial fisheries, these families can be divided into four groups; pelagic sharks, deep-water sharks, coastal sharks and dogfish, and skates and rays, though it should not be inferred that all species in a particular group necessarily have the same management requirements. In the Northeast Atlantic, some species are taken in directed fisheries, but the majority usually appear as a bycatch with other teleost (bony fish) species. Except for the basking shark and porbeagle, none of the elasmobranchs are subject to catch controls and there is, therefore, no obligation for fishermen to record catches in the logbooks used for monitoring quota uptake of commercially important teleosts. Moreover, landings data on elasmobranch species compiled by ICES or FAO are also limited by a lack of species-specific data reported by most countries, and it is difficult to tell from these statistics the contribution of individual families or species to the total elasmobranch landings. As a consequence, there is a lack of information which can be used for the assessment and management of the fisheries for sharks, dogfish, skates or rays.
Within this century, directed fisheries have developed for some elasmobranch species, and the establishment of “hot spots”, in which a locally abundant part of a species' population is fished intensively until it no longer provides an economic resource. This is a particular problem world-wide (Fergusson 1994). Even in the more general, mixed fisheries, there is evidence of changes in species composition in some sea areas, an example being the rays in the North Sea (Walker and Heessen 1996). Unfortunately, and despite the often repeated assertion that elasmobranch fish are relatively vulnerable to exploitation, as they are slow growing, mature late in life and produce small numbers of young compared to marine teleosts, there has been very little active management by any country involved in their fisheries in the Northeast Atlantic.
It has been impossible within the contract to undertake new data extractions or analyses, or to seek help from European colleagues in providing unpublished material for their countries. Whilst the description of fisheries and elasmobranch species taken by them is probably adequate, we are aware that there may be local management issues which have not been covered. However, regulation and conservation of shark, dogfish, skate and ray stocks is essentially an international responsibility, and we have tried to provide an appropriate factual overview of the situation in the Northeast Atlantic. It should be noted that the evaluation of the efficacy of management objectives, policies and regulations with respect to elasmobranch fisheries in FAO Area 27 is that of the authors, and does not necessarily reflect the views of ICES nor CEFAS as an agency of the UK Government.
2. THE FISHERIES
2.1 The resource
In comparison with the commercially important teleost species, such as herring (Clupea harengus) or cod (Gadus morhua), elasmobranchs as a group were lightly exploited until relatively recent times in FAO Area 27 (Figure 1). In 1969, the total landings of all non-teleost fishes from the Northeast Atlantic amounted to around 127 000t, out of total landings of all fin fish of over 9 million tonnes (ICES Fisheries Statistics). The respective figures in 1982 were around 77 000t out of a total of almost 10 million tonnes, which suggests that the relative abundance of elasmobranchs has decreased significantly. Table 1 shows the trends in elasmobranch catches between 1935 and 1994.
Northeast Atlantic (FAO Area 27) showing ICES fishing area statistical divisions
2.2 Species composition of elasmobranch fisheries
i. Pelagic sharks
The pelagic sharks are well represented in the fisheries of the Northeast Atlantic, though only a few members of this group are identified at a species level in FAO statistics; these are the basking shark (Cetorhinus maximus), blue shark (Prionace glauca) and the porbeagle (Lamna nasus). Other sharks in this group that are caught regularly but not recorded separately in the landing figures include the shortfin mako shark (Isurus oxyrinchus), thresher shark (Alopias vulpinus) and tope (Galeorhinus galeus, which is also taken in coastal fisheries).
ii. Deep-water sharks
Around 12 species of shark are caught regularly in the deep-water fisheries conducted on the western slope of the continental shelf in the Northeast Atlantic (Table 2). The most important family is the Squalidae, of which the most regularly landed species are the Portuguese shark (Centroscymnus coelolepis), long-nose velvet dogfish (Centoscymnus crepidater), leafscale gulper shark (Centrophorus squamosus), gulper shark (Centrophorus granulosus), kitefin shark (Dalatiaslicha), birdbeak dogfish (Deania calcea), great lanternshark (Etmopterus princeps) and velvet belly (Etmopterus spinax). The blackmouth catshark (Galeus melastomus), which belongs to the family Scyliorhinidae, is also taken in landings from the deeper waters.
|Year||Piked dogfish||Catsharks and nurse-hounds||Skates and rays||Various non-teleosts||All elasmo-branchs||All fin-fish|
|1935 (1)||na||25 020||42 437||na||67 457||3 721 661|
|1939 (1)||na||22 403||35 402||na||57 805||3 513 256|
|1948||na||22 943||60 508||na||83 451||5 003 545|
|1950||na||27 832||52 124||na||79 956||4 861 680|
|1955||na||44 038||50 094||na||94 132||7 933 523|
|1960||na||55 531||53 116||na||108 647||7 567 421|
|1965||27 987||22 957||43 321||6 802||101 067||8 933 479|
|1970||33 209||11 440||33 680||33 355||111 684||9 988 123|
|1975||30 254||10 396||25 257||31 773||97 680||11 279 257|
|1980||31 737||10 179||27 296||12 679||81 891||11 009 241|
|1984||38 464||9 667||32 699||6 823||87 651||10 399 547|
|1985||40 384||9 916||33 539||6 892||90 731||9 996 625|
|1990||28 257||10 901||31 066||9 377||79 601||8 148 738|
|1994||19 621||7 629||24 722||12 794||64 766||10 019 050|
(1) Excluding Spain.
na = Data not available.
iii. Coastal sharks and dogfish
The main species in this group are the spurdog (Squalus acanthias), small-spotted catshark (Scyliorhinus canicula), nursehound (Scyliorhinus stellaris) and the smooth-hounds (Mustelus spp.). Collectively, landings of this group comprise around half the total weight of elasmobranchs taken from the Northeast Atlantic.
iv. Rays and skates
Rays and skates (Rajidae) have contributed more than 40% by weight to the reported landings of elasmobranchs from the Northeast Atlantic in recent years. Statistical information by species is limited, as many European countries do not differentiate between species in landings statistics and they are collectively recorded as skates and/or rays. Around 10 ray and skate species are regularly landed from north European waters, of which 6 are listed separately in FAO statistics. The cuckoo ray (Raja naevus) and the thornback ray (Raja clavata) are the most important species landed by France, whose catches of Rajidae far exceed the declared landings of any other country fishing the Northeast Atlantic.
|Pelagic sharks||Deep-water sharks||Skates and rays|
|Bigeye thresher shark||Alopias superciliosus||Gulper shark||Centrophorus granulosus||White skate||Raja alba|
|Thresher shark||Alopias vulpinus||Leafscale gulper shark||Centrophorus squamosus||Common skate||Raja batis|
|Basking shark||Cetorhinus maximus||Long-nose velvet dogfish||Centroscymnus crepidater||Blonde ray||Raya brachyura|
|Tope||Galeorhinus galeus||Black dogfish||Centroscyllium fabricii||Sandy ray||Raja circularis|
|Shortfin mako shark||Isurus oxyrinchus||Portuguese shark||Centroscymnus coelolepis||Thornback ray||Raja clavata|
|Porbeagle||Lamna nasus||Kitefin shark||Dalatias licha||Shagreen ray||Raja fullonica|
|Blue shark||Prionace glauca||Birdbeak dogfish||Deania calcea||Small-eyed ray||Raja micro- ocellata|
|Hammerheads||Sphyrnidae||Great lanternshark||Etmopterus princeps||Spotted ray||Raja montagui|
|Smooth lanternshark||Etmopterus pusillus||Cuckoo ray||Raja naevus|
|Coastal sharks and dogfish||Velvet belly||Etmopterus spinax||Long-nose skate||Raja oxyrinchus|
|Smooth-hounds||Mustelus spp||Blackmouth catshark||Galeus melastomus||Starry ray||Raja radiata|
|Small-spotted catshark||Scyliorhinus canicula||Knifetooth dogfish||Scymnodon ringens|
|Nursehound||Scyliorhinus stellaris||Greenland shark||Somniosus microcephalus|
|Spurdog||Squalus acanthias||Little sleeper shark||Somniosus rostratus|
2.3 Geographical range and migration
i. Pelagic sharks
Sharks, especially the large pelagic species, are highly mobile and the populations of many species are widespread in the North Atlantic. The blue shark is one of the most wide-ranging of all sharks, being found throughout tropical and temperate seas from about 60°N to 50°S latitude. It is occasionally occurs close inshore. As the blue shark prefers temperatures of 12–20°C it is found at greater depths in tropical waters (Last and Stevens 1994). Tagging studies have revealed extensive movements with numerous trans-Atlantic migrations (Casey 1985; Stevens 1990). Blue shark released in the Western Approaches to the English Channel have been recaptured off northern Spain, the Canary Islands and in the western Atlantic. One fish tagged off south-west England was recaptured in the South Atlantic off South America.
The blue sharks' complex migration patterns are related to reproduction and the distribution of prey. There tends to be a seasonal shift in population abundance associated with oceanic convergence or boundary zones as these are areas of higher productivity and availability of prey species. In the Northeast Atlantic, adult females are found during winter in the area between the Canary Islands and African coast at about 27–32°N (Munoz-Chapuli 1984). Adult males are found further north off the Portuguese coast, along with juvenile and sub-adult females that have moved south from northern Europe. Immature males are not caught in this region and may be offshore. In spring and summer, immature and adult males and adult females are found between about 32–35°N. The immature females migrate north to northern Europe, where they are common in summer, particularly off the coast of south-west England (Stevens 1976). Juvenile blue sharks remain in nursery areas in the Mediterranean and in the Atlantic between Portugal and the Bay of Biscay, and do not take part in the extensive migrations of the adults until they reach a length of about 130cm (Stevens 1976; Munoz-Chapuli 1984).
Other species of large shark tagged in the Northeast Atlantic have also shown a considerable range of movement. Stevens (1990) reports that tope tagged off England were recaptured throughout the eastern Atlantic from southern Spain to north-west of Iceland, though this species is not found in the Northwest Atlantic. The distribution of the porbeagle extends from the Barents Sea to Northwest Africa (Compagno 1984). porbeagle tagged off southern England have been recaptured over a wide area between northern Norway, Denmark and northern Spain. The basking shark is known to range between Madeira and Iceland, but is generally only observed in northern latitudes in the summer months (Kunzlik 1988). All these species, and another less common species, the thresher shark, are regarded as having an homogenous stock structure in the eastern Atlantic.
ii. Deep-water sharks
There is little published information other than research vessel survey data regarding the distribution of the deep-water sharks. They are taken on the slope of the continental shelf, mainly in depths of water from 400 to 1800m, and most species appear to have a wide ranging distribution extending from Iceland southwards to at least the Azores. Research vessel surveys have shown some specific distribution differences and depth preferences (Table 3).
|Leafscale gulper shark||Northeast Atlantic, slopes, islands and oceanic mid- water.||400–1875m|
|Throughout North Atlantic||500–800m|
|Portuguese shark||Throughout North Atlantic, on slopes and locally oceanic||400–2700m|
|Long-nose velvet dogfish||Northeast Atlantic slops||270–1270m|
|Kitefin shark||Throughout North Atlantic||90–1800m|
|Birdbeak dogfish||Northeast Atlantic||400–1260m|
|Great lantern shark||Throughout North Atlantic||300–2210m|
|Smooth lantern shark||Central Northeast Atlantic, slopes and oceanic||300–1000m|
|Velvet belly||Eastern Atlantic slopes||70–2000m|
|Knifetooth dogfish||Northeast Atlantic on and around slopes||400–1875m|
|Greenland shark||Throughout North Atlantic including Arctic waters.||Arctic shelf and down to 1200m|
|Little sleeper shark||Central Northeast Atlantic to Porcupine west slope||200–1000m|
iii. Coastal sharks and dogfish
The spurdog is a far-ranging species of small shark, for which directed fisheries have developed from time to time during the 20th century wherever its abundance has made this an economic proposition. This small squaloid shark is usually associated with coastal regions throughout the temperate and sub-Artic zones of the North Pacific and North Atlantic oceans. In the Northeast Atlantic, its main distribution is from the west coast of France, around the British Isles north to Iceland and off the Norwegian coast. The spurdog has been of commercial importance to international fisheries in the North-East Atlantic for at least 70 years, and has been subject to morescientific research than any other elasmobranch, especially regarding its migratory patterns and life history characteristics. Tagging studies have shown consistent evidence of annual migrations through coastal waters and across the North Sea between Scotland and Norway (Holden 1965; Aasen 1961–64). However, the results in these publications relate to fish which had been at liberty for relatively short periods (3–4 years), and there is evidence from tagged spurdog recaptured in excess of 7 years after release that the population exhibits somewhat different long-term movements (Vince 1991). Early recaptures of fish tagged off south-east Ireland have extended from the Irish Sea to the west coast of Scotland, but progressively more fish were reported from the North Sea after 10 years at liberty. It has also been suggested that migration patterns may vary during different stages of maturity (Shafer 1970). Holden (1965) suggested the presence of two separate stocks of spurdog in the Northeast Atlantic; a Scottish-Norwegian and a Channel stock, while others consider only one stock to exist in these waters (Gauld and McDonald 1982; Vince 1991). Templeman (1944) has reported trans-Atlantic migrations of fish tagged in Canadian waters. Although the extent of mixing between Northwest and northeast Atlantic spurdog populations is not known, a wide dispersion of recoveries has been common to all spurdog tagging experiments, and it is clear that this small shark has an extensive distribution.
One tagging experiment carried out in the Minch on the west coast of Scotland in 1962 released 2008 spurdog 1998 of which were males. This experiment was notable for a number of reasons; it demonstrated that fishing grounds can be inhabited by single sex shoals and that they have a remarkable capacity for survival after release. Recaptures have been made every year until 1990, since when a further 6 have been returned, the most recent being in July 1997, 35 years after release.
iv. Catsharks and nursehounds
Although little studied, the catsharks in the Northeast Atlantic appear to be much more sedentary than the spurdog, and the few available tagging results indicate quite restricted movement (CEFAS, unpublished data). The small-spotted catshark is common on all coasts, from Mediterranean latitudes to southern Norway, and contributes substantially to the landings of ‘dogfish’ from the North Sea, English Channel and Celtic Sea. The Nursehound is found on rough, even rocky grounds to the south and west of the UK, extending to the Mediterranean, but, because it is comparatively scarce, does not contribute much to commercial fisheries.
v. Skates and rays
Rays and skates have a benthic distribution, occupying the same spatial distribution and trophic level as teleost flatfish. All have a commercial value, except for the starry ray (Raja radiata), though even this species is landed incidentally in the Danish industrial fisheries. Collectively, the skates and rays have a wide distribution in coastal waters of the Northeast Atlantic, though individual species can be localised in a relatively small area. Tagging has been carried out on a number of ray species in the North Sea, Irish Sea and English Channel. The pattern of returns from the majority of experiments has shown that rays exhibit a small range of movement (in comparison with spurdog), and that each species has a preferred habitat. This is especially true of species such as the small-eyed ray (R. micro-ocellata), which is locally abundant in the Bristol Channel but rare elsewhere.
The most abundant of the Raja species is the cuckoo ray, the distribution of which extends from northern Scotland down the west side of the UK to the Mediterranean, and includes the Irish Sea and the north-west sector of the North Sea. This small ray lives in shallow to moderate depths from 20m down to about 150m.
The thornback ray is the second most abundant ray species named in the FAO list and has a wider distribution than the cuckoo ray, being found all round the UK and southwards to Madeira. It typically occurs in water depths down to 60m and has a coastal distribution on the continental shelf. The thornback ray population in the North Sea is considered to consist of a number of local concentrations between which there is a regular exchange of individuals (Walker et al. 1997). This species has been tagged in significant numbers in the North Sea, Irish Sea, and Bristol Channel. The majority of those recaptured had moved no further than 50–60 km from the release position, though some fish were observed to move up to several hundred km. These results confirm what Stevens (1936) reported, that 71% (144) of recaptured tagged thornback rays released in the English Channel had moved less than 8km, while only 5% (11) had travelled over 32km. None were recovered from a position greater than 80km from the point of release.
The spotted ray (Raja montagui) is intermediate in size and found from north Scotland down the west side of the UK and south to the Mediterranean, usually in water deeper than 25m, and is most common between 60 and 120m (Wheeler 1969). Tagging studies carried out to the east and west of the UK have revealed only small movements within the study areas (Walker et al. 1997; Pawson and Nichols 1994).
In contrast to the three ray species described above, the ‘skates’ (common and long-nose) are much larger and tend to be found in deeper water. The common skate (Raja batis) has the more widespread distribution of the two, ranging from Iceland and off Norway in the north to Madeira in the south, and is found in water from 30 to 600m deep (Wheeler 1969). Over 200 large common skate were tagged and released off the west coast of Scotland between 1975 and 1988 and the majority (75%) of recaptures came from the area of release. A group of five were taken between 70 and 200km distant from the release site, and two fish moved much further to the north: one being recaptured 130km off south west Norway (Sutcliffe 1994). Common skate move inshore in summer in Icelandic waters and there is an associated return to deeper water in the winter, a migration which probably also takes place elsewhere (Wheeler 1969).
The long-nose skate (Raja oxyrinchus) is found in moderately deep water from 150 to 900m, but juveniles can be found in shallower water. The distribution of this skate is not as extensive as that of the common skate, being found off southern Norway, around Scotland and down the west side of the UK south to the Mediterranean.
Although total landings of skates and rays in the Northeast Atlantic seem to be reasonably stable, the relative abundance of some species has changed (ICES 1989; Dulvy 1995). In the past, the common skate was considered to be extensively distributed throughout the central and northern North Sea, but in the last few decades this species appears to have retreated to the very northern North Sea and is currently caught only off the Shetlands (Walker 1995). Brander (1981) reported the extirpation of the common skate from the Irish Sea, which was apparently the first case of a marine fish brought to the brink of local extinction by commercial fishing. Although the common skate was once one of the three most important species landed by France, it is currently rare in landings and, according to Munoz-Chapuli et al. (1993), white skate (Raja alba), common skate and blonde ray (Raja brachyura) have all disappeared from the southern Bay of Biscay. Now caught mainly in the Celtic Sea, the common and long-nosed skates account for only about 4% of the total elasmobranch landings in France (ICES 1989).
In the North Sea, rays have been subjected to intensive exploitation and have experienced similar declines (Walker 1995). ICES (ICES 1995b) reports that no rays were caught along the Dutch coast from 1958 to 1994 in an area in which the thornback ray had previously been common.
2.4 Distribution of fisheries directed at elasmobranchs
From a management viewpoint, it is useful to distinguish between fisheries in which particular elasmobranchs are the target species, and those fisheries which are directed at teleosts but use catching gears which take a bycatch of elasmobranchs. In the first case, management actions can be taken which are designed to directly change the level or pattern of exploitation on elasmobranch populations, whereas any effect of management in bycatch fisheries is incidental to, and may in fact conflict with, the conservation needs of the target species.
i. Basking shark
The geographical and temporal distribution of the Norwegian domestic basking shark fishery changes markedly from year to year, and this was suggested by Stott (1982) to be due to the unpredictable nature of the sharks' inshore migration. The Norwegian fleet has prosecuted local fisheries from the Barents Sea to the Kattegat, as well as more distant fisheries ranging across the North Sea and as far afield as the south and west of Ireland, Iceland and Faeroe.
ii. Other pelagic sharks
The fisheries for large pelagic sharks contrast sharply with those for the coastal dogfish and rays. Many of the sharks taken in directed fisheries or as a bycatch are also likely to have been the subject of fisheries elsewhere. The prime example of this is the blue shark, which is taken on surface long lines set by Spanish fishermen as far south as the west coast of Africa. Other pelagic sharks that are an important component of the same fisheries are the mako, hammerhead (Sphyrnidae) and bigeye thresher (Alopias superciliosus) sharks.
In the summer months, blue sharks move north to cooler waters, as far as the south coast of England and southern and western coasts of Ireland, where they are subject to a recreational rod-and-line fishery and where a directed fishery using longlines and gillnets (which also takes spurdog and hake) commenced in 1991. Blue sharks are also taken as bycatch in the offshore fisheries targeting tuna with longlines and driftnets beyond the slope of the continental shelf.
The most important source of mortality on blue sharks probably arises where they are taken as a bycatch in the longline and driftnet fleets targeting tuna and billfish, particularly from nations with high seas fleets such as Japan, Taiwan, Korea and Russia. Because there is usually no requirement for these fisheries to record their blue shark catch, its magnitude (and the consequent mortality) is not reflected in catch statistics. Due to the increasing price paid for shark fins, however, the difference between target and bycatch species in these fisheries is becoming less clear.
Other pelagic species that have been the target of both recreational and commercial fishing are porbeagle and tope. The porbeagle is taken in much lower numbers than the blue shark, and is subject to different fisheries along its migratory route. Traditional fisheries for porbeagle in the northern North Sea have operated out of Norway, Denmark and to a lesser extent the UK, and landed weights reported to FAO have declined since the 1960s. The porbeagle is also targeted by French longliners in the Celtic Sea and Bay of Biscay, from where over 77% of the total French catch of 640t recorded by all gears in 1993 was landed. The total landings of porbeagle by all countries from the Northeast Atlantic in 1993 was 839t.
There is no directed commercial fishery for tope in European waters (though some recreational anglers specialise in tope catching), but they are taken as a bycatch in bottom trawl, net and line fisheries of all countries bordering the Northeast Atlantic, and especially by French vessels fishing in the English Channel, Western Approaches and northern Bay of Biscay (Bonfil 1994). According to French catch statistics for 1987, it ranked third (at about 600t, some 6% of the total) in shark catches behind spurdog and small-spotted catshark. Tope also feature in catch statistics for Portugal and in the Azores with 20–30t/yr recorded for the latter between 1980 and 1988 (Da Silva, paper to ICES SGEF, Dublin 1989).
iii. Deep-water sharks
A deep-water fishery has recently developed along and beyond the continental slope, generally in depths greater than 200m, in response to declining catches of whitefish species such as cod, hake (Merluccius merluccius) and pollack (Pollachius pollachius), which are usually caught in shelf seas (ICES 1993). This fishery targets species such as grenadiers (Macrouridae), argentines (Argentina spp), and several shark species, which previously had not been exploited, but now find a ready market. In Spain, a fishery for deep-water sharks started in 1991 in ICES Sub-area VII, where a number of longliners, which traditionally fished for hake in this area but had difficulties in maintaining profitability, began to fish for sharks in waters deeper than 1000m. A fishery for sharks also developed from Cantabrian and Asturian ports, where, in 1992, 17 vessels landed 340t of a mixture of Gulper sharks, Lanternsharks, Kitefin shark and Birdbeak shark. In 1993, 10 vessels discharged 452t (ICES 1995).
There is also a directed fishery for deepwater sharks is in the Azores, and has existed for over 20 years. The kitefin shark has been targeted by both gillnets and handlines which tend to catch mostly males and females respectively. The landings peaked at 950t in 1981 and have decreased since then to 309t in 1994, possibly as a result of high levels of exploitation. Market fluctuations in the price of the oils extracted from the livers appear to play an important part in influencing the level of activity of vessels that periodically target deep-water sharks.
By far the most important of the directed fisheries for elasmobranchs are those targeting spurdog, which is the most widespread of the coastal elasmobranch species in the Northeast Atlantic. This species moves in large packs, often segregated by size and sex and, as a consequence, catch rates by commercial and survey fishing can vary considerably. Longline fishermen in particular have used “feelers” - short lines with few hooks - to locate a spurdog pack before deploying the main gear. Between 1950 and 1970, Norwegian long-liners working north of Bergen took 70% of the total international landings from the Northeast Atlantic; on average, half of these were taken in Norwegian coastal waters and the remainder were caught around the islands to the north of Scotland. Norwegian landings of spurdog have been sustained by the development of an extensive offshore fishery based on large vessels using long lines fishing waters as far afield as Orkney and Shetland (Bonfil 1994; Hjertenes 1980), though these fisheries are seasonal and have recently become sporadic. Today, the spurdog is exploited off the west coast of Norway and around the British Isles. Although the majority is taken as bycatch in otter trawls and seines aimed principally at whitefish, directed fisheries for this species continue to operate locally and seasonally. In the Celtic Sea, it is caught primarily by French trawlers, and by English and Welsh longliners and in fixed gill nets in the Bristol Channel and Irish Sea. Scottish and Irish trawlers and seiners fish for spurdog off the west coast of Scotland, and some English longliners from the east coast moved into this area after continuous poor fishing in the North Sea (Vince 1991). Recent landings figures (ICES Fisheries Statistics 1996) show over half the total landings of spurdog as coming from the northern North Sea and west coast of Scotland. Landings by Scottish vessels accounted for 43% of the total of 16 000 landed from the Northeast Atlantic in 1996.
v. Skates and rays
In addition to the fisheries mentioned above, there are a number of small fisheries targeting various species of Rajidae in relatively limited geographical areas. Fishing methods include longlines set for species such as the common skate and, more recently, large meshed fixed gill nets have been set to catch Thornback and Spotted rays in coastal areas. However, directed fisheries for rays have been few and small in scale compared with those for spurdog. France, Ireland and the UK have traditionally had some directed fisheries for rays and collectively landed the largest proportion of the catch. Most of the French catches of rays come from the Celtic Sea and English Channel, though they are taken mainly as a bycatch during bottom trawling. The cuckoo ray has contributed over 30% of the total French ray catch in recent years, and comes mainly from the south Celtic Sea and north Biscay. The thornback ray is often the target of directed seasonal fisheries by France, which takes most of the catch of this species from the Celtic Sea and Irish Sea. Trawlers operating out of Milford Haven in the 1950s and 1960s targeted rays, especially thornback rays off the south east coast of Ireland. This fishery is still continued on a smaller scale by vessels from the Irish Republic. During the last decade, small-scale fixed-net fisheries targeting thornback ray have developed off the west and north coasts of Wales, and similar fisheries using lines, fixed nets and trawls have taken place in localised coastal regions in the North Sea. A summary of gears used by the main countries to catch elasmobranch species is given in Table 4.
2.5 Elasmobranchs as bycatch
Historically, the value of commercial fisheries directed at elasmobranch species has ranked low in relation to other marine fisheries (Bonfil 1994). Most fisheries taking elasmobranchs are directed at commercial teleost species, and the following section presents an overview of these bycatches, country by country.
The French fleets catch about 20 species of elasmobranchs and land a greater weight of these fish from Northeast Atlantic waters than any other European country. Most elasmobranch landings are taken as bycatch and occur in all gear sectors of the commercial fleet. These landings have been decreasing over the last 15 years and were reported to FAO as totalling 40 000t in 1981 and around 22 000t in 1996. In 1993, trawlers landed around 85% of the elasmobranch catch of which the most abundant species were the small-spotted catshark (4445t, 21.5%), cuckoo ray (2936t, 14.2%), spurdog (1760t, 8.5%) and thornback ray (1531t, 7.4%). The blue shark is taken as bycatch in the tuna fleet fishing mainly with pelagic gillnets and longlines.
The increase in deep-water trawling by large French vessels (>30m) since 1990 has resulted in significant landings of deep-water sharks. In 1993, their shark bycatch represented 7% of the total catch in this fishery. The two most abundant species were the leafscale gulper shark and Portuguese dogfish. France also lands a number of deep-water squaloid shark species grouped under the trading name ‘Siki’.
The landings of elasmobranchs by France shown in Tables 5 and 6 are probably the best indication available of the species composition taken from the sub-divisions of the Northeast Atlantic.
ii. United Kingdom
After France, the UK ranks second in landed weight of elasmobranch species in Europe (in 1990 France reported 38% and UK 24% of the European total) and, like France, the majority is taken as bycatch in fisheries for other species. Most of the landings of dogfish and rays arise as bycatch in towed demersal gears, usually in otter trawls and seines aimed principally at gadoids and flatfish, although in some coastal areas there are a few, seasonal, small-scale directed fisheries. The ‘dogfish’ landings consist principally of the spurdog and small-spotted catshark. Although not segregated into separate species when landed, the rays are likely to consist mainly of thornback, cuckoo and spotted rays. Landings of pelagic sharks taken on lines, gillnets and trawls in fisheries directed at other fish are mainly the porbeagle, blue shark and, more rarely, thresher shark.
|Species||Denmark||France||Germany||Iceland||Ireland||Netherlands||Norway||Portugal||Spain||Sweden||UK (E&W)||UK (Scot)|
|Porbeagle||LL||LL,DN||Tr||GN,RL||LL||LL||Tr, GN, LL||Tr,LL,S|
|Greenland shark||Tr, L?||RL|
Bold indicates directed fishery.
Key:LL = longline;
GN = gillnet;
DN = driftner;
Hn = harpoon;
Tr = trawl;
Sn = seine;
RL = rod and line (sport).
In Ireland, sharks are chiefly taken as bycatch in non-targeted fisheries, and especially in bottom-set gillnets. The most frequently caught species are tope and porbeagle, both of which are regarded as a valuable bycatch, though it is unlikely that a directed fishery would be sustainable (Berrow 1994b). The majority of sharks caught in surface drift-nets for salmon and driftnets used for albacore tuna (Thunnus alalunga) are blue shark and porbeagle, although the basking shark has been recorded occasionally in the salmon drift-net fishery.
The Norwegian catch of elasmobranchs has, for the most part, come from directed fisheries, principally for spurdog and basking shark. Only the skates and rays are the result of bycatches in trawl and line fisheries, and Norwegian landings statistics reveal that it is only the catches of these species that have increased or remained steady over the years 1970 to 1994. The total catch is probably higher than recorded landings, which in recent years have seldom exceeded 1000t and come mainly from the northern North Sea, Norwegian Sea and around Rockall.
Spain has not traditionally targeted sharks, but bycatch landings between 1950–1973 were fairly stable, averaging 11 700t/yr. Spain was ranked fifth in the Northeast Atlantic fishing area with regard to shark landings in 1991 (Stamatopoulos 1993). The extensive longline fishery for swordfish (Xiphias gladius) out of Vigo in northern Spain takes a bycatch of sharks, and landed 2408t of blue shark (237 660 individuals) in 1984, in addition to 304t of mako shark and 20t of porbeagle (Mejuto 1985). Other pelagic sharks that are an important component of the same fisheries are the hammerhead and bigeye thresher sharks. Spanish vessels also catch small-spotted catshark and smoothhounds on the continental slope off Cantabria. A bycatch of skates and rays in excess of 1000/yr was landed between 1985 and 1992 by the Spanish Atlantic trawler fleet, mainly from the Bay of Biscay and Portuguese waters, though the species composition is not recorded.
|ICES div.||IIa||IIb||IVa||IVb||IVc||Vb||VIa||VIb||VIIa||VIIb||VIIc||VIId||VIIe||VIIf||VIIg||VIIh||VIIj||VIIk||VIIIa||VIIIb||VIIIc||VIIId||VIIIe||IXb||Xa||XII a||Total||%|
|various skates and rays||10||1||27||2||88||0||34||2||269||4||10||483||519||203||584||271||33||4||215||129||3||0||2893||14.5|
In mainland Portugal, skates and rays, mainly thornback and blonde rays, are landed by artisanal demersal longliners and bottom trawlers, whose catches ranged between 1000 and 2300t during 1986–93. Landings from coastal trawlers ranged between 350 and 600t for the same period. Small-spotted catshark, tope and, to a lesser extent, smoothhounds are also caught in the these fisheries. Shark landings from artisanal fisheries ranged between 800 and 1100t during 1986–90. while between 250 and 500t were landed from coastal and offshore trawlers. Several species of shark are also caught off the Portuguese continental coast by trawlers fishing for crustaceans and include the small-spotted catshark, blackmouthed catshark and, in deeper water, gulper shark, birdbeak dogfish, kitefin shark, smooth lanternshark and velvet belly (Anon 1997).
Large pelagic sharks are taken in the Azores as a bycatch in the longline fishery directed at swordfish. Landings of blue shark peaked at 170t in 1992 and, though the discards of blue shark were not quantified, they are likely to have been high. Landings of shortfin mako shark have never exceeded 14t, and landings of other species (which include the porbeagle, thresher, bigeye thresher, hammerheads and tope) were 3t or less during the period 1987–1993. The bycatch of elasmobranchs from the demersal longline fishery for hake comprises mainly tope and thornback ray and the landings peaked at 115t and 55t respectively in 1994. Again, discards are high for both species. Other species of ray are caught in small quantities in coastal waters and some deep-water sharks and dogfish are caught offshore.
In 1989, only three of the 37 species of cartilaginous fish found in Icelandic waters were considered to be commercially important (ICES 1989). In 1996, elasmobranch landings from Icelandic waters comprised the Greenland shark, 63t; starry ray 1493t; spurdog 157t and common skate 181t (ICES Fisheries Statistics). Other species reported by Iceland in the last 12 years have been porbeagle shark and shagreen ray (Raja fullonica), although both of these were only caught sporadically.
Other European countries which land elasmobranchs as a bycatch from fisheries directed at teleosts are the Netherlands, Belgium, Germany and Sweden. Table 7 provides a summary of the landings of dogfish, skates and rays from FAO Area 27 by country and ICES division in 1996.
2.6 Associated species either as bycatch or discards
The main species of teleost fish landed from fisheries in which elasmobranchs are taken as a bycatch have been covered in the previous section, and there are relatively few species which are caught in directed fisheries for sharks, skates or rays. The specialised line fisheries for blue and porbeagle sharks and spurdog appear not to have a bycatch problem, though it is likely that any other species taken will be of a marketable size and not discarded. Tangle nets set for rays also have turbot (Scopthalmus maximus) and anglerfish (Lophius spp) as target species, and these gears may take a bycatch of crustanceans (particularly edible crabs), many of which have to be discarded because they are difficult to disentangle whole from the gear.
In the Northeast Atlantic, fisheries employing a wide range of gears to target a variety of elasmobranch species may be found in the coastal zone from northern Norway in the north to Portugal in the south. Of the coastal species, the spurdog is the most widespread and the most intensively fished. The extensive migrations of this species can result in a group of fish being the target of a fishery in the English Channel or Western Approaches, and later the same group of fish can be taken in another fishery in the North Sea or off the west coast of Scotland. A similar scenario exists for the highly migratory pelagic sharks, particularly the blue shark which, though rarely targeted commercially, is an important bycatch of many fisheries that use nets and lines (including sport fisheries). This type of multi-fishery targeting does not occur with the other coastal elasmobranch species, due to the limited migrations made by the species concerned. Consequently, coastal fisheries, which may involve a number of different types of gears, tend to exploit local populations of catsharks, hounds and rays.
|Sea area||North Norway||Skag-Kat||Norweg Sea||Iceland||Facroe||West Scotland||Rockall||Irish Sea||West Ireland||English Channel||Bristol Channel||South Ireland||Biscay||Portugal||Azores||East Greenld||Total|
|ICES div.||I+II||IIIa||IV||Va||Vb||VIa||VIb||VIIa||VIIb,c||VIId,e||VIIf||VIIg-k||VIII||IX||X + XII||XIV|
|Dogfish and hounds|
|Sea area||North Norway||Skag-Kat||Norweg Sea||Iceland||Facroe||West Scotland||Rockall||Irish Sea||West Ireland||English Channel||Bristol Channel||South Ireland||Biscay||Portugal||Azores||East Greenld||Total|
|Skates and rays|
|Sea area||North Norway||Skag-Kat||Norweg Sea||Iceland||Facroe||West Scotland||Rockall||Irish Sea||West Ireland||English Channel||Bristol Channel||South Ireland||Biscay||Portugal||Azores||East Greenld||Total|
|ICES div.||I+II||IIIa||IV||Va||Vb||VIa||VIb||VIIa||VIIb,c||VIId,e||VIIf||VIIg-k||VIII||IX||X + XII||XIV|
The majority of deep-water elasmobranchs landed from the Northeast Atlantic are taken as a bycatch in trawl fisheries operating in water depths in excess of 500m, but more typically beyond 1000m. Since 1991, the expansion of effort by large French vessels into deeper waters to the west of the UK (sub-areas VI & VII) has resulted in increasing catches of deep-water sharks. To the south, in ICES divisions VIII and IX, Spanish and Portuguese longline fisheries are directed at a number of deep-water shark species.
2.8 Development and current status of the fisheries
2.8.1 Historical development of the fishery and its present status in general terms
Historically, few of the elasmobranchs landed from the Northeast Atlantic have been the product of directed fisheries, and the majority of shark, dogfish, skate and ray landings are made as a bycatch from fisheries directed at teleost species. The major part of the elasmobranch landings from the Northeast Atlantic are caught by 9 nations, for which the evolution of coastal and open-water/offshore fisheries has been shaped by local geological features. Most of the Atlantic coastal countries of Europe lie adjacent to the wide, relatively shallow continental shelf, and their fleets have traditionally fished on the shelf in the Baltic, North, Irish and Celtic Seas, English Channel and the Bay of Biscay. In Spanish and Portuguese waters, however, the continental slope lies closer to the coast, and these nations also have a long-standing practice of open-water fisheries. Coastal fin-fish fisheries in the Northeast Atlantic area employ a variety of fishing vessel designs and catching gears. These include demersal beam and otter trawlers, pelagic trawlers, purse seiners, fixed gillnetters, dredgers and small artisanal vessels employing lines and nets. Open-water fisheries generally involve pelagic trawlers, tuna and billfish longliners and driftnetters, and open-water purse seiners. Since 1990, the expansion of deep-water trawling and longlining for previously unexploited demersal species has resulted in an increase in the numbers of deep-water sharks landed. Descriptions of these catching methods can be found in Sainsbury (1997).
i. Basking shark
The earliest directed fisheries for pelagic sharks in the Northeast Atlantic were probably for basking shark. Several nations have exploited these large planktivores during their inshore movements in the warmer months, and the history of some fisheries extends back hundreds of years. Until this century, such fisheries generally depended on the use of hand harpoons launched from small boats to catch their quarry, but this has gradually given way to the use of non-explosive harpoons fired from small whale guns and, in one case, large gillnets.
Norwegian fishermen have always been the major catchers of basking sharks in the Northeast Atlantic. Their fisheries generally started around April and May, occasionally as early as March in some years, reach a peak in June and finish in August or, less commonly, September (Myklevoll 1968). The fleet is composed of small wooden vessels 15m to 25m in length which are sometimes used for hunting small whales as well as basking sharks (Kunzlik 1988). Norwegian fishermen are known to have been actively fishing for porbeagle off the Scottish coast as early as 1934 and it is thought that they first started fishing there for basking sharks in the immediate post-war years after the establishment of several native Scottish fisheries. Similarly, Norwegian vessels took basking sharks in Irish waters followed the establishment of Irish fisheries there after the second world war. The sizes of the early Norwegian catches from waters off Scotland and Ireland are not known. During 1959–1980, catches ranged between 1266 and 4266 sharks/yr, but have since declined (Kunzlik 1988). This decline is due to a combination of factors, including a shrinking market due to the discovery of a richer source of squalene from the deep-water sharks such as the gulper and leafscale gulper sharks (Myklevoll 1989).
ii. Other pelagic sharks
Many of the sharks taken in directed fisheries, or as a bycatch, are likely to have been the subject of fisheries elsewhere. The prime example of this is the blue shark, which is taken on surface longlines set for swordfish by Spanish fishermen as far south as the west coast of Africa. This fishery has developed rapidly since the 1940s and is considered to be the most important in the Northeast Atlantic. Some 23 000 blue sharks are estimated to be taken annually, up to 82% of which are discarded due to the low value of blue shark compared to that of swordfish or even mako and porbeagle sharks (Vas 1995; Mejuto 1985). Further north, blue sharks are taken by swordfish longline vessels operating from northern Spain (Mejuto 1985), and they have also been the target of recreational anglers from ports in south-west England since the early 1950s, though the catches taken by this fishery have fallen considerably since 1960. More recently (in 1991), a small-scale commercial longline fishery was started off the south coast of Cornwall. Blue sharks are also taken in a sport fishery along the southern and western coasts of Ireland, where it is estimated that anglers catch a minimum of 1500 blue sharks/yr (Vas et al. 1996). The offshore fisheries targeting tuna with longlines and driftnets beyond the slope of the continental shelf also take blue sharks as a bycatch. Some age/size segregation has been noted in blue shark catches, with juveniles featuring predominately in the catches off the south west of the UK, in contrast to larger mature fish found off the Canary Islands and Portuguese coast (Munoz-Chapuli 1984).
The porbeagle shark has also been subject to targeted fisheries over a long period and has been exploited commercially since the early 1800s, principally by Scandinavian fishermen. Traditional line fisheries directed at porbeagle in the northern North Sea and off the Scottish coast have involved specialised vessels from Norway and, to a lesser extent, Denmark and the UK, and French vessels fishing to the south and west of England. Prior to 1930, the Norwegian fleet used shark lines in the eastern North Sea, mainly during the months July-October. Over the period 1930– 1965, Norway was the principal country fishing for porbeagle, and it extended the fishery to the Orkney-Shetland area and the Faeroe Islands and then to the waters off Ireland and offshore banks by the 1950s. Catches of porbeagles had declined by 1965 and, in order to maintain economic viability, many of the vessels switched to other species or moved to West African grounds to fish for mako shark and swordfish (Gauld 1989). Denmark's small fleet of specialised shark long-line vessels formerly operated in the summer months, predominantly in the North Sea but extending into the North-western Atlantic in the 1980s (Gauld 1989). The only currently active directed fishery for porbeagle are the French longliners which work in the Bay of Biscay and Celtic Sea, but even their activity is now decreasing.
According to Holden (1977) spurdog has been fished in England since the beginning of the 20th century. Landings did not exceed 2850t/yr until 1931, but increased to 7000-8000t by the late 1930s (Gauld 1982). At that time, the spurdog was considered a nuisance in Scotland since it preyed upon other fish caught in driftnets and often damaged the nets. Between 1920 and 1939, Scottish landings of spurdog came from a bycatch in other whitefish fisheries and annual landings fluctuated between 1000 and 2000t.
English and Scottish landings of spurdog remained between 6000 and 10 000t annually from the mid 1950s to the late 1970s, with most catches being taken in two main fisheries. One was off the north and west coasts of Scotland, where Grimsby whitefish trawlers either worked for the whole voyage or stopped for a few hauls on the homeward passage from Iceland or Faeroes to ‘top-up’ a trip. Landings of spurdog were also made by a small fleet of inshore longliners which worked in a seasonally directed fishery off the east coast of the UK (Anon 1991). Other spurdog fisheries have been developed by French trawlers working in the Northeast Atlantic from the Faeroes south to northern Biscay, and by longlining in the Celtic Sea and the western English Channel. Landing statistics are not sufficiently detailed prior to 1978 to determine quantities by species, but it is known that significant quantities of spurdog came from the English Channel, Celtic Sea and North Biscay.
From at least as early as 1930, Norway had fished inshore for spurdog in the Norwegian Sea (Bonfil 1994; Hjertenes 1980). According to Gauld (1982), these landings were destined for wholesale and retail markets in England. However, spurdog did not become an economically viable species to catch in a directed fishery after the Second World War when new markets were established, primarily in France. At this time, the Norwegians developed an extensive offshore fishery based on large vessels using long lines fishing waters as far afield as Orkney and Shetland (Bonfil 1994; Hjertenes 1980). As a consequence, Norwegian landings of spurdog increased steadily from 8767t in 1937 to the peak of roughly 34 000t in 1963, when they accounted for 87% of the total European landings of the species. The Norwegian catch consisted mainly of large individuals, due in part to the imposition of a national 70cm minimum size limit and partly because the large, mature, female dogfish occurred most abundantly on the rough, stony grounds fished by the Norwegian longliners (Holden 1977). Towards the end of the 1970s, many Norwegian vessels were modernised with automatic baiting and handling systems for longline gear, and increased freezing and storage capacities extended their time at sea. Yet spurdog landings continued to decline and, by 1978, the consequent economic problems caused the Norwegian fishery north of Scotland to collapse with a subsequent reduction of the fleet (Hjertenes 1980).
Today, the spurdog is caught around the British Isles, in the North Sea and off the west coast of Norway. Although the majority is taken as bycatch in other fisheries, directed seasonal fisheries for this species continue to operate locally. As in the past, the Spurdog is exploited by towed and passive gear, such as trawls, seine nets and deep longlines (Munoz-Chapuli et al. 1993). In the Celtic Sea, this species is caught primarily by French trawlers, while English and Welsh longliners land most specimens from the Irish Sea. Scottish and Irish trawlers and seiners fish for spurdog off the west coast of Scotland with the recent addition of some English longliners from the east coast that moved into the area after continuous poor fishing in the North Sea (Vince 1991).
iv. Skates and rays
In the years following World War II, a directed fishery for a number of ray species was established by trawlers fishing grounds in the Irish Sea, Bristol Channel and off the west coast of Scotland. Prior to 1960, landings of skates and rays accounted for more than 50% by weight of the elasmobranch catch from the Northeast Atlantic and, in 1948, over 60 000 of these fish were landed from European coastal waters. In recent years (1985-1996), the catch of skates and rays has fallen to between a half or a third of the weight landed in 1948. Holden found 8 different species of rays being landed in 1961-62 by trawlers at Milford Haven from grounds in the Irish Sea. Thornback and spotted rays made up over 70% of the landings by number, and other species were the common skate, and blonde, cuckoo, shagreen, small-eyed and sandy (Raja circularis) rays. Ray fisheries occur in coastal waters and tend to be seasonal and, apart from a few small-scale specialised gears (e.g. large meshed fixed nets, longlines), the landings from the Northeast Atlantic have virtually all been a bycatch from demersal trawling aimed at gadoids or flatfish. Size selection by gear is minimal owing to the shape of rays, but selection on board has occurred to comply with the market's preference for larger fish. The contribution from the North Sea to the total ray landings from the Northeast Atlantic has declined from some 25% in 1955 to around 14% in 1996 (ICES Fisheries Statistics).
2.8.2 Evolution of catch
International landings statistics on elasmobranch species are compiled by ICES or FAO from data collected by national fisheries organisations. Unfortunately, only a small proportion of the landings by most countries is reported by individual species and, for the majority of species, it is impossible to tell from these statistics their proportional contribution to the total elasmobranch landings. Nevertheless, it is apparent that the landings of elasmobranchs from the Northeast Atlantic are higher than in other Atlantic Ocean fishing areas. Total landings increased from 1950 to 1970, followed by a more or less continuous decline interrupted only by a slight increase over a four-year period in the early 1980s, and have now reached pre-1950 levels (Figure 2).
Total landings of elasmobranchs from the Northeast Atlantic 1950–1994 (Anon 1996a)
Compared with the relative stability of overall landings of marine teleosts from the Northeast Atlantic, this decline is thought to be indicative of the lack of sustainability of the elasmobranch populations at current levels of exploitation (Bonfil 1994). However, it is acknowledged by ICES that some elasmobranch landings have not been reported by some countries in recent years. FAO records landings statistics for 10 shark species, 9 ray species and the aggregate categories “rays” and “sharks and rays”. Fishery statistics for the ICES areas have been published in Bulletin Statistique since 1903, in which statistics for elasmobranch species have been tabulated under the following headings; ‘spurdog’, ‘dogfish and hounds’, ‘skates and rays’, and ‘various non-teleost fishes’. As a consequence, monitoring the relative change in abundance or species composition through time has not been possible using these sources.
The historical development of other fisheries is covered in Section 1.2.1 of this report. Catches of both deep-water sharks and large pelagic sharks have increased in recent years as more effort has been directed into fisheries that take these sharks as bycatch.
In the last ten years, catches of basking shark have varied considerably, partly due to the fishes' fluctuating local availability and market prices. Landings by Norway between 1990–1994 ranged from 1623 to 3658t and came from the Norwegian Sea and the northern North Sea (Anon 1995). Table 8 gives the historic series of basking shark catches taken by those countries most involved in this fishery.
* Assumes a mean liver weight of 0.5t.
** Minimum value. Up to 300 taken annually during 1947 and 1948.
Other pelagic sharks
Over the period 1930–1965, Norway was the principal country fishing for porbeagle shark in the Northeast Atlantic. Landings by Norway reached a peak of 3884t in 1933, but declined thereafter and, in 1961, a fleet of Norwegian longliners extended their fishing for porbeagle to Northwest Atlantic waters off the coast of New England and Newfoundland. By 1965, many of the vessels had turned to other species in order to maintain economic viability (Gauld 1989). Denmark's small fleet of specialised shark long-line vessels formerly operated predominantly in the North Sea, but they also extended their range into the Northwest Atlantic in the 1980s. The only directed fishery for porbeagle which is currently active is prosecuted by French longliners in the Bay of Biscay and Celtic Sea, where their activity is also decreasing. According to the FAO Yearbook of fisheries statistics, Porbeagle landings in 1994 by all countries fishing the Northeast Atlantic totalled 985t, of which Norway landed only 25t.
In the UK, a small-scale longline fishery for blue and porbeagle sharks was started off the south coast of Cornwall in 1990. In 1992, vessels registered in England and Wales accounted for 757t of shark, of which half were landed abroad. The equivalent total landings by the 6 boats fishing for sharks in 1994 was 893t, in a fishery which now appears to take place mainly off the shelf edge in the Celtic Sea and west of Ireland.
ii. Deep-water shark
The recently developed fisheries for deep-water sharks were almost non-existent before 1990. An even more recent longline fishery for deep-water sharks started in the second part of 1995 in the Bay of Biscay, taking mainly Portuguese dogfish and also the leafscale gulper shark and birdbeak dogfish in waters of depths from 700 to 1600m. Landings from the gillnet and handline fishery directed at kitefin shark in the Azores peaked in 1981 at 950t and had decreased to 309t by 1994.
Total landings of spurdog from the Northeast Atlantic are difficult to determine for the many years in which some countries combined all species of dogfish in declared landed weights. Even so, ICES and FAO statistics indicate that spurdog landings declined rapidly from the mid-1980s, falling to less than 20 000t in 1994, a drop of more than 50% from the 43 000t reported in 1987 (Table 9). According to Munoz-Chapuli et al. (1993), there was a gradual decline in landings reported from the Scottish-Norwegian area of the Northeast Atlantic, followed by a similar trend in the North Sea, though increases in landings have been reported to the west of the UK.
|Year||Spurdog||All dogfish||Year||Spurdog||All dogfish|
* Figure includes French various non-teleosts.
The pattern of changes in spurdog landings is well illustrated by data from the French fishery, which shows this species was the main shark landed in the early 1980s. French landings of decreased from just under 15 000t in 1983 to 1760t only a decade later, in 1993 (Anon 1996b). Most of the French spurdog landings since 1979 have come from the Celtic Sea where catches peaked at 6000– 8000t in 1981–84 and again in 1987–88, but had fallen to under 1000t by 1993. A similar pattern was observed in the English Channel, with 1500–1800t being landed in 1980–83 and 1240–3000t landed in 1986–88, falling to around 500t in 1995. Landings from the North Sea peaked at 2500t in 1979–81 and have since declined continuously to under 20t by 1994. Landings from the west coast of Scotland, the Irish Sea and west of Ireland also peaked in the mid 1980s, at around 2500t, 1600t and 850t respectively, but together amounted to just over 200t in 1994. Annual landings from the northern Bay of Biscay remained at between 200 and 520t up until 1988, but declined to 150t by 1994.
Norway's spurdog fishery grew rapidly from just under 3000t in 1946 to a peak of around 30 000t per annum in 1961–63. The main fishing grounds were off the west coast of Norway in winter-spring and on the banks north of Scotland in summer-autumn. Tagging experiments had shown that the “Scottish-Norwegian stock” migrated between these two areas, but there was a change in the fishes' migration pattern in the years when Norway's fishery was at its peak. Instead of spending winter off western Norway, the spurdog migrated southward through the North Sea to the Dogger Bank area. Norwegian longliners became aware of this development in 1968 and it led to better catches for about five years. Catches in the North Sea then continued to decline and in 1996 were below 1000t, with only a few larger auto-line vessels fishing seasonally for spurdog. In the late 1980s, a fishery developed in the fjords and coastal waters of Nord-Troendelag (64–65° N, ICES Div. IIa), carried out by small local vessels, mainly with gill nets. This led to a temporary increase in landings, peaking at 5200t in 1991 though catches there had declined to less than 400t in 1996.
Annual landings of spurdog by Iceland from Division Va reported to ICES since 1967 averaged around 20t until 1991, but rose to over 100t in 1992–1995.
The Scottish landings of spurdog from west of Scotland and the northern North Sea reached a peak in 1975/76, when over 10000t were reported, and the fishery has continued to account for landings of at least 4500t each year (8500t in 1995). However, landings by English vessels working in the North Sea have declined from over 4000t in 1981 to around 500t in 1995, whilst there were peak catches in the Irish Sea between 1985 and 1988, at 3–4000t each year, with landings of below 1000t in 1995. A spurdog gill-net fishery developed along the west coast of Ireland since 1976 and catches reached a peak of over 5000t in 1984–88, with landings in 1994 and 1995 of around 1000t.
The Belgian fishery for spurdog takes place in the central and southern North Sea with relatively less activity in the Irish Sea and Celtic Sea, and landings reached a peak of around 1500t in 1966–69, gradually declining to less than 20t in 1995. Reported landings of spurdog by Danish vessels from the North Sea and Div. IIIa peaked at nearly 1500t in 1988 and had decreased to around 150t by 1995 though it is known that other species have been landed illegally as “spurdog” to avoid problems with quota restrictions. Similarly, landings of spurdog by the Netherlands have decreased since 1976. The spurdog is one of the few elasmobranch species taken as bycatch in Germany, mainly by bottom trawls, which has been landed regularly for human consumption. Landings from the North Sea have declined to below 50t in the 1990s.
Skates and rays
The practice in the UK and in Ireland is for four or five species of rays to be landed together in particular size categories, rather than by species, makes the collection of accurate quantitative data by species impossible. However, some segregation does take place on French markets (see Tables 4 and 5), and French fisheries statistics are probably the most detailed in Europe in terms of reporting landings of skates and rays to the species level. Total international catches of rays and skates declined from around 55 000/yr in the mid 1950s to 25 000 in 1975 though there was an apparent increase in the late 1980s, with 38 000 landed in 1988 (Anon 1996b). FAO statistics show that between 20 000 and 30 000 skates and rays are now landed annually in northern Europe. Even as bycatch, catches of 450kg of rays per boat per day were reported from a single area off the Brittany coast by France, with cuckoo and thornback rays the most common species (Munoz-Chapuli et al. 1993). Although skate and ray landings seem to be generally stable in the Northeast Atlantic area, the relative abundance of some species has changed (ICES 1989; Dulvy 1995). The common skate, once one of the three most important species landed by France, is now caught mainly in the Celtic Sea and the long-nosed skate now accounts for only 4% of the total elasmobranch landings in France (ICES 1989).
In the North Sea, skates and rays have been subjected to intensive exploitation and landings decreased significantly during the 1930s, but increased just after World War II during which period fishing had almost ceased (Fig 3). In the southern North Sea landings have declined since 1948 whereas in the northern and central area the major decline started around 1965. Walker (1994) reports that, despite an increase in fishing effort, landings dropped from 12 000 to 5000t between 1954 and 1974. Since the mid-1970s, total landings of rays from the North Sea have remained more or less constant. Although it appears that most species have experienced similar declines in abundance in the North Sea, where once the thornback ray had been the most abundant ray species, the starry ray now comprises 80% of the biomass of the Rajidae (Walker 1995). The life history of the common skate, its large size and commercial importance, make it the most vulnerable of the Raja species and the stocks have, quite predictably, been severely depleted. Nevertheless, it appears that some other species may have experienced changes in growth and maturation which have enabled their populations to be sustained at a higher level of mortality than in the past.
Landings of skates and rays from the North Sea 1900–1995 (ICES 1997b)
2.8.3 Fleet characteristics, evolution of the fleet and fishing effort
Because the major part of elasmobranch landings from the Northeast Atlantic arise as bycatch in fisheries for teleost species, it is only possible to distinguish ‘fleets’ or fishing effort directed at a relatively few species. Moreover, changes in fleet composition and effort of these directed elasmobranch fisheries may be influenced more by socio-economic factors associated with the fisheries in which the boats are involved when they are not fishing for sharks. For example, the Norwegian fleet targeting basking shark is an ageing one, and as the boats reach the end of their useful working life they are being withdrawn from the fishery without replacement. In 1983, 12 Norwegian basking shark boats fished the Irish grounds and by 1987, only seven of these remained on the Norwegian registry of fishing boats. Such a reduction is due, in part, to restrictions on their whaling activities, but the fishery has always been an uncertain one and the problems encountered in catching and marketing basking sharks and their products have discouraged younger fishermen from entering the fishery (S. Myklevoll, pers. comm. to P A Kunzlik).
2.9.1 Shark products
Until this century, basking shark fisheries were essentially artisanal, supplying oil for lighting and tanning and occasionally food and shark-skin leather. Several fisheries developed around the time of World War II in response to the general shortage of commodities. These relied on markets for liver oil products, which later declined in response to increased supplies of mineral oils and the advent of synthetic vitamin A production. Currently, the basking shark is targeted by the Norwegian fishery for its fins and liver oil, the latter being used in lubricating oils, medicines and leather-tanning products (Last and Stevens 1994). The basking shark is also prized for its squalene liver oil fraction for use as a health food (Clarke 1987), though this market has been depressed recently by large amounts of deep-water shark liver oil supplied by Spanish and Portuguese fisheries (Fleming and Papageorgiou 1997).
The Spanish fishery for deep-water sharks started in 1991 and coincided with the emergence of a market for their livers, which comprise between one third and one fifth of the total body weight and yield approximately 70 to 80% oil. In the longline fishery for deep-water sharks which started in the second half of 1995, the sharks were skinned, gutted and landed with the fins for human consumption and the livers sold for production of oil. The main species was the Portuguese dogfish, but the leafscale gulper shark and birdbeak dogfish were also landed.
In the EU, there is a strong demand for sharks as food, with Italy being the largest consumer of shark and dogfish meat. Between 1990 and 1994, this country imported, on average, over 12 000t/yr comprising 67% shark and 33% dogfish, though not all of this came from Northeast Atlantic waters. Marketing of shark products is complex. Some countries within the European Union (EU) import shark and dogfish from outside the EU for processing and later resale within the EU. An example is spurdog, which is exported from the USA to the UK and then sold on to France. However, most of the shark products derived from Northeast Atlantic fisheries are consumed within EU countries (Fleming and Papageorgiou 1997).
France is both the major producer and importer of shark products in Europe. Bonfil (1994) reports that France has a strong and increasing domestic market not only for spurdog, but also for porbeagle - which is particularly highly valued for its meat - and tope for saumonette in school canteens and restaurants. Imports increased after 1982 when large exports of mainly porbeagle and tope to Italy caused a deficit of supply in France, but some problems related to the mercury content of shark meat has recently limited exports to Italy and the effort directed towards porbeagle has been subsequently reduced.
The spurdog landed by English, Scottish and Norwegian vessels in the 1930s were destined for wholesale and retail markets in England, but this species did not become economically viable for directed fisheries until after the Second World War when the Norwegians developed an extensive offshore longline fishery. Demand in the UK came from the fish and chips trade and, though much of the catch was exported to France, a glut of landings in Europe sometimes made selling dogfish difficult and uneconomic. Processors of spurdog wasted little of the raw material. The livers went for oil, the fins for soup, the belly-flaps for smoke-curing, and there were even some experiments with the skins for fashion accessories. Declining landings of spurdog in the UK in recent years have resulted in more imports, especially from the emerging fisheries in North America and Canada. Nevertheless, the UK is still the largest exporter of spurdog in the EU, tending to use mature females because of the size required for fresh, processed backs, about 60% of which is sent to Germany rather than France as formerly (Fleming and Papageorgiou 1997).
Demand for ‘skate’ in the UK and Ireland comes mainly from the fish and chip trade, and the larger Raja species such as the blonde and thornback rays are the most sought after. Much of the skate and ray catch landed in the UK in recent years have been exported to France and Belgium, where there is a strong demand from supermarkets and restaurants and prices are consequently higher. As with dogfish landings, market demand and prices have been the main influence on the retention of skates and rays taken as bycatch in fisheries for other commercial species. Smooth-hounds and small-spotted dogfish are also landed to provide bait in whelk (Buccinum undatum) pots.
The taste for shark fin derivatives is rapidly expanding in Europe. Surveys carried out by TRAFFIC in the UK, between 1994 and 1996, revealed that imported shark fin is marketed as canned soup, dried and processed and is available in supermarkets, herbalists shops, pharmacies and restaurants catering to Asian consumers. Similar scenarios were found in Belgium, France, Germany, Italy, Ireland and Spain. Nevertheless, all fins taken from sharks in Spain are exported to Asian countries, including South Korea, Thailand, China and Japan. Other shark by-products that are found in many EU countries are shark cartilage and capsules, shark liver oil and shark curios. While it is known that much of these materials have been imported into the EU, there is little doubt that some originate from fisheries in the Northeast Atlantic.
In general terms, the markets for the spurdog, coastal dogfish, skates and rays have not seen any radical changes in the past 10 years. The big developments have been centred around the pelagic and deep-water shark species. The ever increasing interest in shark-fin soup, shark cartilage, shark liver oils, and shark skins has created an expanding market world wide. Although concerns about increasing exploitation and the unsustainability of many of the elasmobranch resources have recently been expressed (see Section 2.2), there is no evidence that this has had any practical effect on management policies or actions concerning elasmobranchs in Europe.
2.9.2 Revenues from the fishery
A feature of the market price of shark products is that it relies on supply and demand for the raw material, and this in turn has been strongly influenced by European prices for other fish products. Thus, elasmobranch bycatch will only be landed if the value and quantity of the associated target species is relatively low. It is likely that average market prices of dogfish and rays in the UK reflect actual values on European markets, and we have used these in Table 10 to show historical trends.
|As % of cod.||46.4||60.0||41.7||37.4||62.6||61.9||70.5||77.5||79.6||78.4|
|Skates and rays||62.0||103.0||382.0||381.0||641.0||743.0||813.0||867.0||865.0||893.0|
|As % of cod.||110.7||128.8||79.6||57.5||59.0||64.6||81.1||87.6||97.9||97.0|
N.B. Data for all species for the years 1960 to 1985 were originally calculated as landed weight and have been converted to a live-weight basis for comparison purposes.
It is interesting to see how the prices for cod and ‘dogfish’ (presumably spurdog) have changed over the past 36 years. The consistent increase in the relative price of dogfish illustrates the increase in the strength of demand in the European market. The market for skates and rays, in contrast, appears to be less strong now than thirty years ago, though prices have improved in the last decade.
2.10 Economics of the fishery
The majority of the elasmobranchs landed from the Northeast Atlantic are taken as bycatch in fisheries directed at teleosts. With restrictive quotas on many of these stocks, the contribution by the non-teleost fish to the value of landings is increasingly important and can make the difference between loss and profit for the fishermen. However, the few traditional directed fisheries targeted at spurdog, basking shark and porbeagle are all in decline, and many vessels engaged in these fisheries have been redirected to other target species, or have retired from fishing altogether. It appears, then, that the reduced availability (rather than the market value) of the majority of elasmobranch species has been the main reason that fisheries in which they are the principal component of the catch have become unprofitable.
There is no financial support at the European level for the fisheries other than to assist with decommissioning costs under the EU Multi Annual Guidance Programme for fleet restructuring (MAGP), though this should have no immediate impact on the economic viability of remaining fisheries other than through reducing competition for resources. We are unaware of any national subsidies specifically in support of elasmobranch fisheries nor have we any other information regarding nature of capital inputs, expenditures etc. in elasmobranch fisheries.
In the UK, landing charges are applicable to elasmobranch and other fish species by value or quantity and vary depending on the port and district, and a national levy on the value of all landings is taken to support the government agency responsible for technical support and development of marine fisheries - the Sea Fish Industry Authority.
2.11 The fisheries workforce
The complex mixture of countries, fleets, fisheries and species that contribute to the landings of elasmobranchs from the Northeast Atlantic makes it difficult to present a detailed description of the workforce. National statistics (e.g. UK MAFF Sea Fisheries Statistics) can be found listing numbers of fishermen employed both part-time and full-time by region, port or fleet sector, but a breakdown by directed fisheries is seldom unavailable. It is likely, nevertheless, that the majority of the elasmobranchs landed have been caught by full-time professional fishermen.
The pelagic sharks are taken in both directed fisheries and as bycatch from gillnets and longlines. The latter, in particular, is a labour-intensive method of fishing by comparison with trawling, and is therefore likely to employ greater numbers of people per vessel. Similarly, vessels targeting spurdog with lines are also likely to employ more crew, although vessels which have been equipped with auto-line equipment will have less crew on board. However, there is no evidence that fisheries taking elasmobranchs employ more, or less, crew than other fisheries.
Trawl fisheries that take elasmobranchs as bycatch are extremely varied ranging from small, single-manned day-boats to large freezer trawlers and employing 10 to 30 crew. Terms of employment also vary from fisherman who are vessel owners to those employed by a fishing company on a wage or share basis.
Where national fishing licences have been sold to companies from other European countries, national regulations have sometimes led to limited employment of fishermen from one country on boats registered by a second country. An example of this is the employment of UK residents on board mainly Spanish or Dutch-crewed vessels registered in the UK.
The obligation to comply with EU fleet restrictions under the MAGP has led to reductions in the number of vessels in most European countries and a consequent loss of jobs in the fishing industry. There is no reason to suppose that these reductions have been greater for vessels landing elasmobranchs than for any other vessels, except possibly the specialised fleets directed at basking and porbeagle sharks for which decommissioning may have been a readily acceptable option.
3. MANAGEMENT OBJECTIVES
In common with the majority of commercially exploited marine resources in the Northeast Atlantic, and not excluding the major species for which there are Total Allowable Catches (TACs), there are no explicit management objectives for elasmobranch fisheries. Although TACs do not have to be set, the International Council for the Exploration of the Sea (ICES), which provides advice to national administrations and to the European Commission on the sustainable management of marine fish stocks, has been given the task of identifying biological reference points consistent with the precautionary approach and helping to define management objectives as a basis for advice for some elasmobranch species.
3.2 The fisheries within the context of national fisheries policies
Where they exist, national objectives that apply to all fisheries affect the management of elasmobranch fisheries. In practice, however, each country with fleets fishing in the Northeast Atlantic is concerned mainly with assuring its fishermen access to the waters and resources upon which they rely for their income and livelihoods. This is largely achieved through national allocations of TACs within the EU and agreements and exchanges of fishing opportunities between EU and third countries. There are no particular exceptions for elasmobranch fisheries, though they are less likely, or even unlikely, to figure in the relevant negotiations between ministers and with the Commission.
3.3 Objectives for the management of the shark fisheries
We are not aware of any specific objectives set for the management of elasmobranch fisheries. However, sharks and other cartilaginous fishes have recently become the focus of increased attention on the part of national, regional and international management authorities, Conventions and non-governmental organisations. This is the result not only of concerns for the sustainability of elasmobranch fisheries, but also the significant wildlife and wider marine ecological implications of their exploitation and trade. Concerns have largely focused on the inadequate or inappropriate management of most directed and incidental shark fisheries and the lack of data on stocks, fisheries (including landings, bycatch, and discards), trade and biology required for the formulation of management advice. It is no longer acceptable to avoid action because of a lack of evidence (Article 7.5 of the FAO Code of Conduct), and there is an increased tendency for elasmobranchs (and other commercial fish species) to be proposed for protected status through addition to the relevant appendices of international wildlife and environmental conventions and national legislation. As a result, there is an overlap of interests between international bodies, such as ICES, FAO, ICCAT and IUCN, and other environmental non-governmental organisations, from which several international initiatives have arisen. Since this is the context in which any management objectives and strategies for elasmobranch fisheries in the Northeast Atlantic will be set, a review of these initiatives is presented below.
The 9th Conference of the Parties (CoP) to the Convention on International Trade in Endangered Species (CITES), held in November 1994, adopted a Resolution on Sharks (Conf. 9.17, Trade in Sharks and Shark Products) which has resulted in several significant new international initiatives on the monitoring and management of elasmobranchs. The Resolution directed the CITES Animals Committee to compile and review existing data on the biological status, including reproduction and management constraints, and factors (directed and bycatch fisheries, habitat degradation etc.) influencing the status of shark species subject to international trade, and to prepare a discussion paper on these data for the 10th CITES Conference in June 1997. It also requested FAO and other international fisheries management organisations to establish programmes to provide biological and trade data in cooperation with all nations utilising and trading in sharks and to assist States to collect species-specific data. The Animals Committee recommended that the CoP endorse a number of actions directed towards the full implementation of the ‘Shark Resolution’, including initiatives to improve identification, recording and reporting at species level of landings, bycatch and trade, and for new research and management efforts.
At the Intermediate Ministerial Meeting on the Integration of Fisheries and Environmental Issues in Bergen, March 1997, Ministers recognised the desirability of an ecosystem approach to fisheries, environmental protection, conservation and management measures, and the need to further integrate fisheries and environmental policies to protect the environment and to ensure the sustainability of its fish stocks and associated fisheries. Ministers agreed that the fishing mortality rate (in the North Sea) should be reduced or controlled so that stocks are rebuilt to, or maintained at, a sustainable level, and competent authorities were therefore invited to consider the establishment of priorities for the elaboration of stock assessments and forecasts, or other appropriate stock indicators, for a number of named species or species groups, including sharks, skates and rays. As the international scientific organisation responsible for research and independent scientific advice on living marine resources and environment issues in the Northeast Atlantic, ICES had indicated that it would attempt to provide the necessary technical information to enable establishment of target and limit reference points, and to present stock assessments and forecasts or other appropriate stock indicators, for elasmobranchs within a ten-year time frame from initiation.
The UN Agreement on Straddling Fish Stocks and Highly Migratory Fish Stocks facilitates implementation of the UN Convention on the Law of the Sea (UNCLOS) provisions relating to the conservation and management of high seas fish stocks. It is complemented by the FAO Code of Conduct for Responsible Fisheries and will establish rules and conservation measures for high seas fishery resources to protect marine biodiversity, monitor fishing levels and stocks, provide accurate data reporting and minimise bycatch and discards, and gather reliable, comprehensive scientific data as the basis for management decisions. It mandates a precautionary, risk-averse approach to the management of the relevant species when scientific uncertainty exists. The Agreement also directs States to pursue co-operation in relation to these species through appropriate sub-regional fishery management organisations or arrangements.
Under UNCLOS, oceanic sharks found in the Northeast Atlantic and defined as highly migratory species, or which may qualify as a ‘straddling stock’ under Article 63(2) of the Convention, include the basking, thresher, hammerhead and mako sharks. It is considered that coordinated management and assessment of the entire populations of these migratory sharks would promote an understanding of the cumulative impacts of fishing effort on their status. Similarly, the Bonn Convention (on the Conservation of Migratory Species of Wild Animals) recognises the need for countries to cooperate in the conservation of animals that migrate across national boundaries or between areas of national jurisdiction and the high seas if an effective response to threats operating throughout a species' range is to be made.
A number of wildlife conventions have also started to address the issue of elasmobranch conservation. Some of these, for example the Barcelona Convention for the Protection of the Mediterranean Sea (1976) and the Berne Convention (on the Conservation of European Wildlife and Natural Habitats), should provide full protection for the white shark (Carcharodon carcharias), basking shark and giant devil ray (Mobula mobular), and regulate exploitation of shortfin mako, porbeagle, blue shark, white skate and angelshark (Squatina squatina), but only in the Mediterranean Sea. The Shark Specialist Group (SSG) of the International Union for the Conservation of Nature and Natural Resources (IUCN) has prepared a Status Report which will update and extend the 1996 IUCN Red List of Threatened Species, which includes several North Atlantic species, including kitefin shark, basking shark and porbeagle. The UK Steering Group Biodiversity Report ‘Meeting the Rio Challenge’, published in 1996, includes basking shark, porbeagle, blue shark and tope in a list of species which are of conservation concern and which may be considered in future revisions of the appendices of the European Habitats Directive (Council Directive 92/43/EEC).
3.4 The objective setting process
As explained above, there are no explicit management objectives for elasmobranch fisheries, though ICES has been given the task of identifying biological reference points consistent with the precautionary approach and helping to define management objectives as a basis for advice for some elasmobranch species. Unless there is a move away from a reliance on purely scientific, biological information for setting management aims towards more socio-economic considerations, the stakeholders, i.e. those with a financial interest in the fishery, will not be involved in the objective setting process.
At present, ICES provides advice to fishery managers which allows them to understand the effects of fishing and breeding success on stocks and yields to the fishery. Stock assessments are used to trace the response of a species' population to exploitation and to evaluate the likely effects of any future management measures, such as a particular TAC, closed fishing areas, or increased mesh sizes. This provides the scientific basis for decisions taken by the Council of Ministers of the European Community on TACs in forthcoming years. A stock is considered by scientists to be outside safe biological limits if the spawning stock has fallen, or at current fishing rates is likely to fall, to a level at which the average recruitment of juvenile fish is reduced. For stocks which are considered to be outside safe biological limits, advice is given on what measures are needed to return the spawning stock to levels which are safe, ideally based on a knowledge of how growth and survival vary under different environmental conditions.
Where the data are inadequate to define the state of the stock, advice may be still possible on the extent of likely gains and losses that will result from changes in fishing effort and, at the least, precautionary levels of catch or effort which would sustain the stock and its fishery.
Clearly, the objectives setting process is not satisfactory from the point of view of conservation of elasmobranch stocks, but a lack of objectives may be seen as a benefit by many stakeholders who's fishing activities have been increasingly restricted by direct catch and effort controls on other species taken in their fisheries. Within the Northeast Atlantic, the issues of resource rent and notions of equity and efficiency do not appear to arise with respect to elasmobranch fisheries.