|Scientific Name:||Galeorhinus galeus (Linnaeus, 1758)|
|Red List Category & Criteria:||Vulnerable A2bd (Regional assessment) ver 3.1|
|Assessor(s):||McCully, S., Dureuil, M. & Farrell, E.|
|Reviewer(s):||Simpfendorfer, C. & Dulvy, N.|
|Contributor(s):||Walker, T.I., Cavanagh, R.D., Stevens, J., Carlisle, A.B., Chiaramonte, G.E., Domingo, A., Ebert, D.A., Mancusi, C., Massa, A., McCord, M., Morey, G, Lawrence, J., Serena, F. & Vooren, C.M.|
|Facilitator/Compiler(s):||Walls, R., Pardo, S.A. & Dulvy, N.|
European regional assessment: Vulnerable (VU)
Tope (Galeorhinus galeus) is a widespread, mainly coastal, temperate demersal shark that is fished throughout its range. It is caught as bycatch in mixed demersal and pelagic fisheries especially by French vessels fishing in the English Channel, Western Approaches and northern Bay of Biscay. In Europe, this species is important in recreational fisheries. Trends from 19 years of survey data of various parts from the Northeast Atlantic suggest this species is declining at a rate that would be consistent with a 38% decline over three generation spans (90 years), and even though little is known of this species in Mediterranean waters, the same decline is inferred to have occurred throughout its whole European distribution. Therefore, based on the estimated decline and the low productivity of this shark, it is assessed as Vulnerable in European waters under criterion A2bd.
There is believed to be a single stock of Tope (Galeorhinus galeus) in the Northeast Atlantic, extending from southern Norway and Scotland, southwards to the coast of northwest Africa and the Mediterranean Sea (ICES 2012). Within this range, the North Sea, waters west of Scotland, the Celtic Sea, English Channel, Bay of Biscay region, Iberian waters and the Azores are believed to be important habitat for the species; whereas the Norwegian Sea, Baltic waters, Iceland and the Faroe Islands are considered areas where it is only an occasional vagrant. It is suggested that the Northeast Atlantic and Mediterranean stock is isolated from other stocks around the world, with little to no gene flow between them (Chabot and Allen 2009).
Tagging studies (Central Fisheries Board, Ireland) have shown movements between the Northeast Atlantic and Mediterranean Sea, also with wide ranging movements tagged off southwest Ireland to the Azores and Canary Islands (ICES 2007). Therefore this species is considered as one stock.
Native:Albania; Algeria; Belgium; Bosnia and Herzegovina; Croatia; Cyprus; Denmark; Egypt (Egypt (African part), Sinai); Faroe Islands; France (Corsica, France (mainland)); Germany; Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Iceland; Isle of Man; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Malta; Monaco; Montenegro; Morocco; Netherlands; Norway; Palestinian Territory, Occupied; Portugal (Azores, Portugal (mainland)); Slovenia; Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Sweden; Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); United Kingdom (Great Britain, Northern Ireland)
|FAO Marine Fishing Areas:|
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
In the Northeast Atlantic, research vessel survey data reveal a decline in abundance indices by 38% since 1993 (Dureuil 2013), which is also suspected to have occurred over three generation spans (90 years). The relative exploitation rates are at levels that, on average, have been greater than that which is sustainable since 1997. In accordance, the fishing mortality from 1992 to 2012 for the central North Sea may have been two to four times greater than sustainable levels. Therefore, the spawning stock size of a cohort would have been reduced to approximately 15% of its exploited spawning stock biomass (Dureuil 2013). Within the English Channel there has been a decline in survey catch per unit effort (CPUE) of approximately 66.6% over the period 1988 to 2008 (Martin et al. 2010).
Tope landings throughout the Northeast Atlantic region have decreased by 83% in the past twenty years from a peak of 1,754 tonnes (t) in 1983 to the lowest record in the time series of 301 t in 2011 (ICES 2011). In the Baltic and North Sea region, landings steadily decreased between 1978 and 2011 (ICES 2012). Landings from waters off west Scotland, the Celtic Seas and the English Channel are relatively high, but also highly variable, with an overall decreasing trend since 1978 (ICES 2012).
This species is now rare in the Mediterranean Sea, and while formerly common in the Adriatic Sea, it has not been captured there in the past half century. The analysis of the MEDITS program data from 1994-1999 shows a very low frequency of occurrence for this shark in the Mediterranean Sea (only five positive hauls or 0.05 %). Its overall biomass was estimated to be 0.2 kg/km2 for the Mediterranean Sea. The standing stock biomass was estimated at 126 t (0.23%) (Baino et al. 2001). Off Italy, Relini et al. (2000) reported catch in only one of the 11 zones studied as part of the Italian national project (9,281 hauls in total, around the Italian coast, from 1985-1998), although data on biomass for this species were not provided. Tuna trap data from the Northern Tyrrhenian Sea from 1898 to 1992 shows a steep decrease in abundance of catches (80 individuals between 1898 and 1905; only eight for the 1906 to 1913 period and zero from 1914 to 1922) (Vacchi et al. 2002). Data from the MEDITS program for the Adriatic Sea were compared with those from the survey Hvar, carried out in 1948 (Jukic-Peladic 2001). Although no data on individual species captured biomass are reported, Tope appeared in the 1948 survey, but not in the MEDITS program. In Tunisian waters, where there exists a lower fishing pressure than off the northern Mediterranean coasts, the species is considered to be very rare (Bradai 2000).
Ferretti et al. (2013) noted that although offshore grounds of the Adriatic Sea remained almost unexploited until the end of World War II, the elasmobranch community surveyed was characterized by small, productive elasmobranchs. Larger, less resilient meso-predatory species such as Tope, which used to be common or seasonally abundant throughout the basin in the 19th and early 20th century (Marchesetti 1882, Ninni 1912, Paolucci 1901, Fortibuoni et al. 2010), were already scarce or under detectable levels (present in less than 5% of tows) likely due to decades of directed and incidental coastal fishing (Marchesetti 1882, Fortibuoni 2010). The Hvar and Zupanovic surveys operating in the Mediterranean Sea between 1948 and 1957 caught 18 Tope specimens in the Adriatic Sea, while the corresponding surveys since 1957 have never encountered the species again (Ferretti et al. 2013).
No species-specific catch data for the Mediterranean Sea and off northwest Africa were available in 2012 (ICES 2012). Overall, available landings appear relatively stable between 1982 and 2003 at around 500 t per year and at 400 t per year since 2004, with a drop to 300 t in 2011. However, the absence of some recent national data restricts the interpretation of recent trends. These older survey data suggest early depletion of Tope at least in shallow waters in this area, which could also have occurred in other Mediterranean areas where similar practices historically operated.
Considering that the stock of Tope is continuous throughout European waters, it is inferred that a similar decline to that of Northeast Atlantic waters is true for the Mediterranean Sea, therefore the species is inferred to have undergone a decline of 38% over the three-generation period through its European distribution.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Tope is most abundant in cold to warm temperate continental seas, from very shallow water to well offshore (Ebert and Stehmann 2013), being primarily found near the bottom but ranges through the water column even into the pelagic zone. In the English Channel, Tope were most abundant in the west, particularly in the deeper waters of the ‘narrows’, between the Cherbourg Peninsula and Isle of Wight, where the seabed is pebbly and tidal currents strong (Martin et al. 2010). These species also showed patches of lower density in some shallower coastal waters in the eastern part of the English Channel.
The maximum size varies considerably: the maximum size recorded is ~ 200 cm total length (TL) for females in the Mediterranean Sea (Capape and Mellinger 1988) and 169 cm TL for a female in the North Sea (McCully et al. 2013) but can be somewhat smaller in other areas (e.g., the Southwest Atlantic with a maximum size of 155 cm for females and 148 cm for males (Peres and Vooren 1991)). Differences are also apparent in the size at maturity in different regions. Size at sexual maturity ranges between 120 and 135 cm TL for males and 134 to 140 cm TL for females (Olsen 1954, Capape and Mellinger 1988, Peres and Vooren 1991, Freer 1992), although Ripley (1946) noted the onset of maturity at 150 cm TL for females and McCord (2005) reports that 50% of males are mature at 101 cm TL. The size at maturity of females in the Northeast Atlantic was suggested to be 155 cm TL for females and 121 cm TL for males (Dureuil 2013), based on data from the Azores, Madeira (Couto 2013) and the Mediterranean Sea (Capape and Mellinger 1988).
This shark is live bearing without placenta, with average litters of 20 to 35 pups; as few as six and as many as 52 observed with an average of 35 in the Northeast Pacific (Ripley 1946, Ebert 2003). Parturition occurs in spring or early summer after a gestation period of ~ 12 months; the young vary in length at birth between 26 and 40 cm TL, depending on the region. The litter size increases in larger females. These may reflect real differences or may be due to the difficulties of sampling a species, which shows marked temporal and spatial sexual and size segregation, and which makes extensive movements. The generation length of this species is estimated to be around 30 years.
The annual rate of population increase (λ) has been estimated by Cortes (2002) at 1.077 (95% C.I. 1.037 to 1.128) and the natural mortality by Smith et al. (1998) at 0.113 year-1. The intrinsic rate of population increase for the Northeast Atlantic population was estimated at 0.062 year-1 and the natural mortality at 0.094 year-1 (Dureuil 2013).
This species makes extensive migrations, for example, animals tagged in the United Kingdom and Ireland showing mixing throughout their Northeast Atlantic distribution and being recaptured as far away as to the north of Iceland (2,461 km), the Canary Islands (2,526 km) and the Azores (1,610 km off the coast of Portugal) (Fitzmaurice 1979, Holden and Horrod 1979, Stevens 1990).
Little is known regarding critical habitats but nursery areas may occur off Portugal and around the Canary Islands (Muñoz-Chápuli 1984), in the southern North Sea, especially along the Frisian Islands (Dureuil 2013) and possibly in the Bristol Channel, United Kingdom (see Walker 1999 for further details). Greater abundances of mature individuals have been found off the northern Irish coast, the southern Irish Sea and the east coast of England (Dureuil 2013).
|Generation Length (years):||30|
|Use and Trade:||Tope has a long history of exploitation in target fisheries in most parts of its range where the species has been in demand for liver oil, meat and fins.|
There is accidental capture of pups on nursery grounds in gillnets of small mesh size and recreational fishers operating in inshore shallow areas. Habitat degradation in potential nursery areas due to development and siltation may also negatively affect recruitment to populations of this species. Other threats are habitat degradation by the effects of trawling through disturbance of substrates (Walker 1998).
Currently, Tope is typically a bycatch of mixed demersal and pelagic fisheries, especially French vessels fishing in the English Channel, Western Approaches and northern Bay of Biscay. Landings data are unreliable as many nations that land tope will report an unknown proportion of landings in aggregated landings categories, for example, ‘Dogfish and Hounds’ (ICES 2012). However, species-specific landings of Tope are available from 1975, with regularly reported catches from France, Portugal and the UK. Overall, reported Tope landings have varied around 500 t through 1990-2000s, but have slowly decreased from 713 t in 2000 to 333 t in 2012. The main proportion of Tope landings are made by France and the UK from the north and along the west coast of the British Isles, with landings ranging from 155-394 t from France and from 98 t to 15 t (2000-2012). In the late 1980s, Tope was among the most important species in commercial shark catches of France and catches were declining (Bonfil 1994). Similar declines in landings have been seen from Iberian waters with Portuguese landings decreasing from 142 t to 47 t (2000-2012).
In demersal trawl fisheries, Tope of 50 to 94 centimetres TL are generally discarded, while those over 94 centimetres are often retained. In drift and fixed net fisheries, Tope are mostly retained and ranged mainly from 70 to 124 centimetres (ICES 2012). Tope is also an important target species in recreational sea angling and charter boat in several areas, with most anglers and angling clubs following catch and release protocols.
Although no direct fisheries for Tope exist in the Mediterranean Sea, it was traditionally caught as bycatch in gillnets and trammel nets in the northern Adriatic Sea, also as bycatch of semi-industrial (Adriatic Sea and Sicily) and artisanal fisheries in pelagic and demersal nets, deep longlines, drift lines and troll lines (Fischer et al. 1987). A small directed gillnet fishery targeting Mustelus spp. and Squalus spp. operated off the Balearic Islands in the past which reported catches of Tope. In recent times, only bottom trawl and longline fisheries have reported continuous bycatch of Tope, and such reports are very rare nowadays. The development of the bottom trawl fisheries in the Mediterranean Sea over the first half of the 20th century in the northern range, and during the latter half in the southern range, is considered as one of the principal factors responsible of the decline of many demersal elasmobranch species. In this sense, both overfishing and habitat degradation must be considered as factors potentially responsible for declines.
In Italian fish markets, the product labeled “palombo” is an umbrella term for numerous shark species, one of which has been identified as Tope by Barbuto et al. (2010). Out of the Triakidae species, only Common Smoothhound (Mustelus mustelus) is distinguishable from the others, raising concern as to how much Tope is being sold under the label “palombo”. The grouping of species under one name in this manner makes it impossible to deduce landings trends, as individual species trends are masked by those they are grouped with.
In 2013, the EU banned removal of shark fins on board vessels (CEC 2013), in line with advice from the International Union for the Conservation of Nature’s Shark Specialist Group and other shark fishery experts, in order to enhance enforcement of the 2003 EU ban on shark finning (CEC 2003) and facilitate improved shark fishery data collection. In terms of UK fisheries Tope is prohibited other than using rod and line (with anglers fishing using rod and line from boats not allowed to land their catch) and a Tope bycatch limit of 45 kilograms per day for commercial fisheries targeting other species was established (Statutory Instrument Number 2008/691, ICES 2012).
Tope is listed in Appendix II of the Barcelona Convention, affording it protection from fishing activities taking place in the Mediterranean region. Contracting Parties and Cooperating non-contracting Parties shall ensure that catches of Tope taken with bottom-set nets, longlines and in tuna traps shall be promptly released unharmed and alive to the extent possible, therefore cannot be retained on board, transshipped, landed, transferred, stored, sold, displayed or offered for sale (Recommendation GFCM/36/2012/1). All vessels encountering these species must record information on fishing activities, catch data, incidental taking, release and/or discarding events in a logbook or similar document, then all logged information must be reported to national authorities. Finally, additional measures should be taken to improve such data gathering in view of scientific monitoring of the species.
|Citation:||McCully, S., Dureuil, M. & Farrell, E. 2015. Galeorhinus galeus. The IUCN Red List of Threatened Species 2015: e.T39352A48938136.Downloaded on 22 November 2017.|
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