|Scientific Name:||Amblyraja doellojuradoi|
|Species Authority:||(Pozzi, 1935)|
Raja doellojuradoi Pozzi, 1935
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||McCormack, C., San Martín, M.J., Stehmann, M.F.W. & Lamilla, J.|
|Reviewer(s):||Kyne, P.M. & Valenti, S.V. (Shark Red List Authority)|
A medium-sized skate (to 69 cm TL) apparently common in Magellanic waters in the Southwest Atlantic off Argentina and the Falkland/Malvinas Islands. Has also been recorded off Chile in the Southeast Pacific. Reported at a wide depth range from 51 to 642 m. Taken in the Dipturus chilensis directed longline skate fishery off Argentina, where it was observed to comprise usually only a few percent of the processed catch but around 8% on one particular haul. The quantity discarded in this fishery has not been reported. It is also a regular bycatch of deeper water benthic trawl fisheries targeting Merluccius hubbsi and Dissostichus eleginoides off Argentina. There are no species-specific bycatch estimates available for these fisheries, however, fishing pressure has increased significantly over the past decade. Around the Falkland/Malvinas Islands the species is a small component in the multispecies skate fishery. There was a gradual decrease in the size of specimens taken between 1993 and 1997 although the data were often sparse. Following fishery declines in the early 1990s, the area south of the Islands was closed to the commercial ray fleet and fishing now occurs north of 52°S. A more recent assessment of the northern ray population has indicated that the CPUE of A. doellojuradoi has increased from 1992 to 2001. There have been no assessments of the population to the south of the Islands since the fishery closure and the species may still be subject to bycatch pressure by deepwater teleost trawlers in this area. The population trends are unknown for the rest of the species' distribution. This species is assessed as Least Concern because there is no evidence of declines and some evidence of increases in CPUE over some of the species' range, although the magnitude of these increases is difficult to assess. Off Argentina, the wide depth distribution of the species offers it some refuge beyond the depth of current fishing pressure, however, especially as fisheries expand into greater depths, there is a need for close monitoring and the collection of species-specific catch and bycatch data where none currently exists.
|Range Description:||Off Argentina from 37°S including the Falkland/Malvinas Islands and the Burdwood Bank, mainly on the shelf edge and slope (Menni and Stehmann 2000). Has also been recorded once off Chile (Bigelow and Schroeder 1965).|
Native:Argentina; Falkland Islands (Malvinas)
|FAO Marine Fishing Areas:|
Atlantic – southwest; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Rather common species in Magellanic waters (Menni and Stehmann 2000).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Medium-sized benthic species distributed in deep temperate waters of the continental shelf and slope. Reported at depths from 51 to 642 m in bottom temperatures ranging from 2.5°C to 6.8°C (Menni and Stehmann 2000), and off Punta Arenas, Chile at 185 m depth. Size at birth has been estimated from 9cm TL and the species has been reported to reach a maximum size of 69 cm TL (FIFD unpubl. data).|
Throughout this section the term rajid refers to skates of both the families Rajidae and Arhynchobatidae.
Skate landings have been increasing considerably in Argentina due to international demand. Prior to 1994, skate captures were less than 1,000 t, however, since that year skate landings increased considerably, reaching >15,000 t in 2001 and 17,465 t in 2003 (Massa et al. 2004).
Amblyraja doellojuradoi is a regular bycatch in bottom trawl fisheries for bony fishes. It has been captured during fishery-independent investigations for hake and other species (García de la Rosa et al. 2000). During 1999, there was a decrease in the captures of rays by the deep sea fishing fleet of around 15% with regard to 1998 (García de la Rosa et al. 2000). There are no species-specific estimates of bycatch for these trawl fisheries and the quantity of A. doellojuradoi taken is unknown.
The species is also taken in the Dipturus chilensis directed skate fishery off Argentina which currently comprises a single vessel. Onboard observation of the fishing operation in 2000 and 2001 indicated that the vessel fished from 37° to 44°S off Argentina in two regions; around 50 m of depth and along the 100m isobath (Colonello et al. 2002). The processed catch composition varied between trips and usually comprised only a few percent of A. doellojuradoi but one haul was comprised around 8% by the species (Colonello et al. 2002). Species-specific data on the discarded portion of the catch was not collected and remains a priority for this and the trawl fisheries.
Since 1989, rajids have been targeted by a Korean fleet utilizing demersal trawls around the Falkland/Malvinas Islands. The fishery initially operated over two main areas, one located on the shelf edge to the north of the Islands, and the other to the south of the Islands. Following declines in CPUE in the early 1990s, the southern area was closed to the fleet in 1996 and the fishery now concentrates in the northern area.
Observer data for the species showed no significant trends in abundance between 1993 and 1997 (Agnew et al. 2000). Mean disc width gradually decreased from 1993 to 1997 although the data were often sparse (Agnew et al. 2000). A more recent assessment of the northern ray population, based on observer data, has indicated that the CPUE of A. doellojuradoi has increased from 1992 to 2001 (Wakeford et al. 2004). Amblyraja doellojuradoi comprised 2.4% of the catch from the northern area of the fishery between 1993 and 2002 (Wakeford et al. 2004). The Falkland/Malvinas Islands have in place a precautionary management system for the skate fishery (see Conservation Actions below), and together with the recovery of biomass (Agnew et al. 2000), what this means is that the fishery will continue into the future, because overall stocks are stable or recovering.
There have been no studies to determine the abundance of this species in the southern area since the rajid fishery closure. However, this species may also be caught as bycatch by finfish trawlers around the Falkland/Malvinas Islands and within the southern rajid closure. While vessels fishing under general finfish licenses are prohibited from targeting rajids, a small bycatch (below 10%) is allowed, therefore rajids to the south of the Islands are continuing to face bycatch fishing pressure.
There are theoretically TACs, minimum sizes and overall annual quotas for quite a number of elasmobranch species in Argentina, however, little attention is paid to these and there is no regular monitoring by authorities (M. Stehmann pers. obs. 2006). Species-specific assessments of direct and indirect catches are a priority.
The following information is taken from Agnew et al. (1999 and 2000) unless otherwise specified.
The Falkland/Malvinas Islands multispecies skate fishery is managed by limiting fishing effort. The effort that each vessel is likely to exert is calculated (based on size, duration of license and past fishing history) and since 1994 only a limited number of licenses are granted to ensure that the total allowable effort (determined from assessments of stock status) is not exceeded. Stock status assessments are not, however, species-specific and a sustainable total allowable effort for the entire stock may not translate to sustainable levels of effort for individual species.
Following declines in CPUE in the early 1990s, in 1996, the southern area (below 52°S) was closed to rajid fishing and the fishery is now resticted to the area north of the Islands. This closure is extended to 50°30´S (between 56°30W and 58°W) during the second season of each year to exclude the skate fishing fleet from Loligo gahi fishing grounds.
All licensed vessels are required to provide daily catch and effort details, including discards of commercial and non-commercial species to the Falkland Island Fisheries Department. There is, however, no requirement to report species-specific information. Scientific observers are deployed onboard skate vessels in order to quantify the catch composition by species and to obtain detailed biological data on individual species.
Agnew, D.J., Nolan, C.P. and Pompert, J. 1999. Management of the Falkland Islands skate and ray fishery. In: R. Shotton (ed.). Case Studies of the Management of Elasmobranch Fisheries. FAO Fisheries Technical Paper 378(1): 268-284.
Agnew, D.J., Nolan, C.P., Beddington, J.R. and Baranowski, R. 2000. Approaches to the assessment and management of multispecies skate and ray fisheries using the Falkland Islands fishery as an example. Canadian Journal of Fisheries and Aquatic Science 57: 429-440.
Colonello, J.H., Massa, A.M. and Lucifora, L.O. 2002. Composición de la captura de rayas del buque palangrero "Sureste 501" en el norte del Mar Argentino. Inf. Téc. DNI Nº 107.
García de la Rosa, S.B., Sánchez, F. and Prenski, B.L. 1999. Rayas, pesca de altura. In: J. Cajal and L.B. Prensky (eds). Diagnóstico de los recursos pesqueros. INIDEP.
IUCN. 2007. 2007 IUCN Red List of Threatened Species. Available at: www.iucnredlist.org. (Accessed: 12th September 2007).
IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.
Menni, R.C. and Stehmann, M.F.W. 2000. Distribution, environment and biology of batoid fishes off Argentina, Uruguay and Brazil, a review. Revista del Museo Argentino de Ciencias Naturales (Nueva Serie) 2(1): 69-109.
Pequeño, G.R and Lamilla, J.G. 1993. Batoideos comunes a las costas de Chile y Argentina-Uruguay (Pisces: Chondrichthyes). Revista Biología Marina, Valparaíso 28(2): 203-217.
Sánchez, M.F. and Mabragaña, E. 2002. Características biológicas de algunas rayas de la región Sudpatagónica. INIDEP Informe Técnico 48.
Wakeford, R.C., Agnew, D.J., Middleton, D.A.J., Pomport, J.H.W. and Laptikhovsky, V.V. 2005. Management of the Falkland Islands Multispecies ray fishery: Is species specific management required? Symposium, 11-13 September 2001: Elasmobranch fisheries: Managing for sustainable use and biodiversity conservation. Journal of Northwest Atlantic Fisheries Science 35: 309-324.
|Citation:||McCormack, C., San Martín, M.J., Stehmann, M.F.W. & Lamilla, J. 2007. Amblyraja doellojuradoi. The IUCN Red List of Threatened Species 2007: e.T63122A12615746.Downloaded on 22 August 2017.|