|Scientific Name:||Hippoglossus hippoglossus (Linnaeus, 1758)|
Pleuronectes hippoglossus Linnaeus, 1758
|Red List Category & Criteria:||Vulnerable A2ce (Regional assessment) ver 3.1|
|Assessor(s):||Munroe, T., Costa, M., Nielsen, J., Herrera, J., de Sola, L., Rijnsdorp, A.D. & Keskin, Ç.|
European Regional Assessment: Vulnerable (VU)
Hippoglossus hippoglossus has a wide distribution in the North Atlantic and can reach depths of up to 700 m. It is a commercially-valued species with a high market price. Hippoglossus hippoglossus has been a targeted species in the western Atlantic since at least the early 1800s. We infer that it has also been a targeted species in the eastern Atlantic since at least the early 1800s. Longevity has been estimated at a minimum of 50 years. Age at first reproduction varies from 4 to 18 years. The Norwegian National Red List calculated a generation length of 15 years for this species. Although it is possible that the generation length for this species is longer than 15 years, prolonged exploitation of this species is likely to have resulted in some truncation of life history, e.g. early maturation at smaller sizes. The working group accepted the generation length of 15 years, and examined population trends over the last 3 generation lengths or 45 years. In Norwegian waters/the North Sea, landing trends have been similar over the 3 generation length time frame, and have been consistently increasing since the mid-2000s. In Icelandic waters there has been a >90% decrease in the biomass index of this species from 1985 to 2013 (28 years). It is inferred that this rate of decline reflects trends over a 45 year/3 generation length time period. Given that the size of the Icelandic stock is considered approximately the same size as the Norwegian stock, there has been an estimated 38 to 45% decline in this species' population in the assessment region. There are no stock assessments available from the region and this species is not managed by ICES. In recent years it has been landed in low numbers in parts of its ranges. Stock levels are so low that the species is nowhere abundant and is uncommonly seen in fish markets. The population is considered relatively stable at low biomass. This species has undergone population declines of approximately 38–45% over three generation lengths. Therefore, it is listed as Vulnerable under Criterion A2bd.
|Range Description:||Hippoglossus hippoglossus occurs from Greenland, Iceland, Barents Sea to Novaja Semlya, the Norwegian coast, Faroe Islands, Great Britain, and Ireland to the North Sea, the western Baltic Sea, and south to the Bay of Biscay (Haug 1990). This species lives at depths from 50 m to 2,000 m (Møller et al. 2010). Elsewhere it occurs from Cape Cod to middle part of western Greenland (Nielsen 1986). This species is found at depths ranging from 50 to 200 m.|
Native:Belgium; Denmark; Faroe Islands; France (France (mainland)); Germany; Guernsey; Iceland; Ireland; Jersey; Netherlands; Norway; Russian Federation (European Russia); Svalbard and Jan Mayen; Sweden; United Kingdom (Great Britain, Northern Ireland)
|FAO Marine Fishing Areas:|
Atlantic – northeast
|Population:||Stock levels are so low that the species is nowhere abundant and is uncommonly seen in fish markets. Within the assessment zone, the population trend is considered stable at low biomass compared to historical levels.|
FAO landing statistics summary
The overall trend in landings of H. hippoglossus declared from the Northeast Atlantic fishing zone from 1950 to 2011 is one of nearly continuous decline. Landings declined by approximately 80% from 1950 to 2011.
Regional population information
This species is still fished in the northeastern Atlantic, however it is landed in low numbers. Total landings north of 62°N have increased in the last year, and catches in Norway are still low (Høines et al. 2009). There has been a slight increase in landings and in the abundance of recruits in recent years. Over the past 3 generation lengths (45 years), the current catch in Norway is similar to that historically observed (e.g., no trend)(K. Nedreaas pers. comm. 2013).
Hippoglossus hippoglossus biomass index in Icelandic waters has declined by >90% from 1985 to 2013 (28 years). It is assumed that over the past 3 generation lengths (1968–2012), biomass in Iceland has declined by at least the same, if not a greater, percentage (Marine Research Institute 2014).
Given that the size of the Icelandic stock is considered approximately the same size as the Norwegian stock, there has been an estimated 38 to 45% decline in this species' regional European population.
Baltic Sea/HELCOM Region: This species was assessed as Not Applicable in the HELCOM Region - less than 2% of the European population can be found in this region. It is rarely found in the Skagerrak. It is occasionally observed in the Belt Sea and the Sound. There was no evidence of regular reproduction within the HELCOM area from 1800-present (2013 HELCOM Red List Assessment).
This species was formerly an important commercial species in the western Atlantic, where directed fishing began in the early 1800s and continued into the early 20th century, when stocks reached the point of collapse. The fishery began to decline by the 1880s. Records are available from 1893 to 2005, with 29 mt recorded from 2001–2005. Record low landings were recorded in the late 1990s (Brodziak and Col 2006). Stocks in the western Atlantic were driven to severely low abundances due to overfishing. Biomass was driven to about 1% of Bmsy and remained there for about a century before rebuilding began. Estimated 50% recovery time is highly uncertain, and is likely around 25 years (Neubauer et al. 2013).
|Current Population Trend:||Stable|
|Habitat and Ecology:||The maximum size for males is 470 cm TL and for females 300 cm TL. The species reaches a maximum weight of approximately 320 kg (Robins and Ray 1986). In Greenland waters this species could reach length of 250 cm (Møller et al. 2010). This species reaches sexual maturity between the ages of four and 18 years and at lengths of 55 cm to 110 cm for males and 110 cm to 135 cm for females (2013 HELCOM Red List Assessment). |
Hippoglossus hippoglossus spawns in deep water from 300 m to 700 m over soft bottom in Norwegian waters (Devold 1938). In the Baltic Sea, this species spawns from December to April from 200 m to 300 m depth. The diet of H. hippoglossus primarily consists of other fish species including cod, haddock, sand-eels, capelin, and herring, but it also feeds on cephalopods, large crustaceans and other benthic species (2013 HELCOM Red List Assessment). Males and females have similar growth rates until they reach sexual maturity when the females have accelerated growth rates and attain a greater maximum size. Hippoglossus hippoglossus can reach at least 50 years of age, and longevity estimates may be underestimated (Muus and Dahstrom 1974, Armsworthy and Campana 2010, Karlson et al. 2013).
Hippoglossus hippoglossus is the largest flatfish occurring in the North Atlantic. It is a benthic species that occasionally is taken off bottom in the water column.
As larvae, this species strongly avoid light and then change at the commencement of exogenous feeding as they become more attracted to light. Light plays a major role in the early life stages of this species (Mangor-Jensen and Naas 1993, Meeren et al. 2013). Newly hatches larvae range from 6 mm to 7 mm SL (Pittman et al. 1990).
A generation length of 15 years was used to assess this species for the Norwegian National Red List. Although the generation length of this species may be longer, because populations have been exploited for a long period of time it is likely that some truncation of the life history has occurred. The working group accepts the generation length estimate of 15 years used by the Norwegian National Red List.
|Generation Length (years):||15|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||Hippoglossus hippoglossus is a commercially valuable species. It has been considered to be an excellent candidate for fish farming (Bjornsson 1994, Bjornsson and Tryggvadottir 1995).|
|Major Threat(s):||Hippoglossus hippoglossus is threatened by overexploitation. It has slow growth rates and matures relatively late in life. It is vulnerable to over exploitation as individuals are harvested before ever reproducing (Sigourney et al. 2006, 2013 HELCOM Red List Assessment). This species aggregates to spawn making it more vulnerable to over exploitation (Høines et al 2009).|
The range of this species overlaps with marine protected areas (IUCN and UNEP 2013). There are no fisheries management plans for this species on a region wide basis. In Swedish waters there is a ban on fishing for this species during the spawning season (December to March).
Recent increases in stock size in Norwegian waters may result from two factors: In Norwegian waters and the Skagerrak there is a closed season during the spawning season. In Swedish and Norwegian waters, trawlers have been outfitted with selection grids and escape panels which have increased the survivorship of Halibut in taken as bycatch in other trawl fisheries.
|Citation:||Munroe, T., Costa, M., Nielsen, J., Herrera, J., de Sola, L., Rijnsdorp, A.D. & Keskin, Ç. 2015. Hippoglossus hippoglossus. The IUCN Red List of Threatened Species 2015: e.T10097A45790126.Downloaded on 23 April 2018.|
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