|Scientific Name:||Chimaera monstrosa Linnaeus,1758|
|Taxonomic Notes:||Chimaera monstrosa is a long established and well-recognized species. Reports of this species from other parts of the world (e.g., South Africa) are misidentifications. A long history of study indicates this species is restricted to the northeast Atlantic, northern part of the Eastern Central Atlantic and the Mediterranean Sea, and the occurrence of populations of C. monstrosa outside this range is highly unlikely.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Dagit,D.D., Hareide, N. & Clò, S.|
|Reviewer(s):||Kyne, P.M., Fowler, S.L., Compagno, L.J.V., Soldo, A. & Valenti, S.V. (Shark Red List Authority)|
This species is widespread throughout the Northeast Atlantic and capture records seem to indicate C. monstrosa is fairly abundant throughout its range. Among chimaeroid fishes this is one of the better known and most studied species, however, data on population structure, biology and ecology is still limited. Appears to prefer upper continental slope habitats at depths of 300 to 500 m with a reported maximum depth of 1,663 m and summer inshore migrations to 40 to 100 m have been observed in some areas. Oviparous with apparent spawning season in spring and summer. This species' unproductive life history characteristics (reaches maturity at 11.2 to 13.4 years; longevity is 26 to 30 years) likely render it vulnerable to exploitation and population depletion, like many deepwater chondrichthyans. Chimaera montrosa is taken in deepwater trawl fisheries in the Northeast Atlantic and is either landed as byproduct or is a component of discarded bycatch. There is a continuing trend of increasing deepwater fishing activities in the North Atlantic, while regulation is often lagging. C. montrosa had the largest discard biomass of all chondrichthyans in a study of the discards of the French bottom trawl fleet from the South Rockall Bank to the northerly slopes of the Wyville-Thomson Ridge and constitutes 13 to 15% of the discards in deepwater trawlers operating off the West Coast of Ireland. Survival rates of discards are likely low given the depths of capture and the fact that many discards are undersized individuals or are unmarketable individuals (suggesting damage). Increasing interest in the production of dietary supplements for human consumption derived from the liver oil of this species suggests that exploitation is likely to increase. Given that this species' preferred depth range is entirely within the range of current fishing activity, its unproductive life history characteristics, and the suspected high rate of mortality to discards, it is assessed as Near Threatened on the basis of a future suspected decline of >20% in three generations, leading to concern that it may soon qualify for Vulnerable A3bd.
Further information is required on deepwater fishing activities (including catch and bycatch levels, effort and trend monitoring). The ban on deepwater trawling below 1,000 m in the Mediterranean may afford this species some protection, but given that its preferred depth range is entirely within the range of fisheries in this region, both present and future fishing pressure is likely unsustainable for C. montrosa.
|Range Description:||Widespread throughout the northeastern Atlantic from the southern Arctic to Morocco (about 80°N to 30°N latitude) including the Mid-Atlantic Ridge and Mediterranean. Common in the western and central Mediterranean, rare in the Eastern Mediterranean, and absent from the North and central Adriatic.|
Native:Albania; Algeria; Cyprus; Denmark; Faroe Islands; France (Corsica); Germany; Gibraltar; Greece; Guernsey; Iceland; Ireland; Isle of Man; Italy (Sardegna, Sicilia); Jersey; Lebanon; Malta; Monaco; Morocco; Norway; Portugal (Azores, Madeira); Spain (Baleares, Canary Is.); Sweden; Tunisia; United Kingdom (Great Britain, Northern Ireland)
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Appears to aggregate in groups and, like other species of chimaeroids, may be segregated by age and sex. Nothing is known of population structure, but this species may be represented by two or more separate subpopulations (e.g., the Mediterranean population may be separate from that found in the North Sea).|
|Current Population Trend:||Stable|
|Habitat and Ecology:||Chimaera monstrosa is a benthopelagic species that prefers upper to middle continental slope habitats at depths of 300 m to 500 m with a reported maximum depth of 1,663 m. Detailed bathymetrical distribution follows: |
Depth distribution according to (Whitehead et al. 1984) is 50 m to 1,000 m and most abundant between 300 and 500 m. Ehrich (1983) however reports that this species is caught at depths of 173 m to 1,663 m to the west of the British Isles. Highest densities were found between 500 m and 700 m. Hareide et al. (1997) reports collection of this species between 630 m and 825 m from the western slope of the Porcupine Bank. No specimens were found between 825 m and 1,400 m. In the Mediterranean Sea this species is abundant in all areas, from 100 m depth, but it is most abundant between 500 m and 800 m (Baino et al. 2001, MEDITS Program). Sion et al. (2004) have also reported several specimens from Balearic Sea at depths of 650 m and from Eastern Ionian Sea at depth of 800 m.
Information from Norwegian exploratory surveys to Hatton Bank (1998-2000) shows a depth distribution of 590 m to 1,230 m in temperatures between 4.7 and 8°C. Additional information on distribution by depth and area, length distributions and CPUE data can be found from Irish and Norwegian trawl and longline survey data to the west of the British Isles and Hatton Bank. Summer inshore migrations to 40-100 m have been observed in some areas.
Provisional and unvalidated, age and growth characteristics determined by Calis et al. (2005), suggest that C. monstrosa is a typical "K-selected" species characterized by a slow growth rate, a long life expectancy, low fecundity, and a high age-at-maturity. In this study, the von Bertalanffy growth parameters were: L∞ = 78.87 (cm), K = 0.0673 per year and t0 = -0.513 (yr). The maximum age estimates observed were 30 years for male and 26 years for female Chimaera monstrosa. However, these ages probably underestimate the true maximum age of this species, owing to the limited sample size examined. Estimated age at first maturity was 13.4 years for males and 11.2 years for females.
Oviparous with an apparent spawning season in spring and summer. Nothing is known of early development. Diet consists mainly of bottom-dwelling invertebrates.
Chimaera montrosa is taken in deepwater trawl fisheries in the Northeast Atlantic and is either landed as byproduct or is a component of discarded bycatch (Crozier in prep.). In a study of discards of the French bottom trawl fleet from the South Rockall Bank to the northerly slopes of the Wyville-Thomson Ridge, C. montrosa had the largest discard biomass of all chondrichthyans (Crozier in prep.). It constitutes 13 to 15% of the discards in deepwater trawlers operating off the West Coast of Ireland (Calis et al. 2005). Survival rates of discards are likely low given the depths of capture, the fact that many discards are undersized individuals or are unmarketable individuals (suggesting damage). There is increasing interest in the production of dietary supplements for human consumption derived from the liver oil of this species, and a directed fishery has the potential to develop in areas of occurrence (Calis et al. 2005).
In ICES Subareas VI and VII the Argentina silus and blue ling landings from directed fisheries increased until 2002, but then declined in 2003. Bycatch species in these areas include bluemouth (Helicolenus actylopterus), greater forkbeard (Phycis blennoides), argentine (Argentina silus), deepwater cardinal fish (Epigonus telescopus), and chimaerids, of which Chimaera monstrosa is the most important (ICES 2005).
Rihan et al. (2005) have also reported this species as a bycatch from bottom gillnets retrieved from 648 nets recovered during a gill net retrieval survey of Rockall and Porcupine Bank at depths of 400 to 1,300 m during August-September 2005. Evidence of significant quantities of lost and abandoned gear in these areas and of excessive discarding in these fisheries due to long soak times lead to serious concerns about the impact of ghost fishing. There is a need for the immediate introduction of effective management measures in these fisheries to control the quantities of gear being fished and soak time (Rihan et al. 2005).
Areas of the Northeast Atlantic, for example the Rockall Trough have been subject to a fairly rapid increase in deepwater fishing activities since the 1990s with overall concern for the sustainability of deepwater fish stocks (Gordon 2003). There is a continuing trend of increasing deepwater fishing activities in the North Atlantic, while regulation is often lagging. Deepwater chimaeroids, like other deepsea chondrichthyans, are potentially at risk from these activities, although little species-specific information is available. Monitoring of deepwater fishing activities, including landings and discards will be essential to ensure that North Atlantic chimaeroid species are not adversely affected. Crozier (in prep.) has shown that high catches of C. montrosa occur between the Rockall Bank to the Wyville-Thomson Ridge, and this likely mirrors catches elsewhere. Further information is required on deepwater fishing activities (including catch and bycatch levels, effort and trend monitoring) in the North Atlantic and the conservation status of this species should be reassessed without delay when such information is available. Both present and future fishing pressure may be shown to be unsustainable for C. montrosa, particularly given its preferred depth range.
The General Fisheries Commission for the Mediterranean (GFCM) banned bottom trawling below depths of 1,000 m in the Mediterranean. This measure was adopted by all members of the GFCM and came into force in September 2005.
Continued monitoring of capture and collection of this species is recommended as well as data collection on locality, size, sex, reproductive condition and depth in order to better understand population structure and trends.
The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and sustainable management of all chondrichthyan species in the region.
|Citation:||Dagit,D.D., Hareide, N. & Clò, S. 2007. Chimaera monstrosa. The IUCN Red List of Threatened Species 2007: e.T63114A12610445.Downloaded on 19 August 2018.|
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