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Psammobatis bergi

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES ARHYNCHOBATIDAE

Scientific Name: Psammobatis bergi
Species Authority: Marini, 1932
Common Name(s):
English Blotched Sandskate
Spanish Raya Reticulada

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2004
Date Assessed: 2004-04-30
Assessor(s): Chiaramonte, G.E.
Reviewer(s): Kyne, P.M., Cavanagh, R.D. & Fowler, S.L. (Shark Red List Authority)
Justification:
Endemic to the Southwest Atlantic from Rio de Janeiro, Brazil (23°S) to Patagonia, Argentina (41°S). It is known to be an abundant small skate (to 60.5 cm total length (TL)) in the coastal waters of Uruguay and Argentina. This skate has very recently become a target species in the multi-species coastal bottom trawl fishery operating in Buenos Aires province (Argentina). Previously it was commonly caught and discarded in this fishery. It is also taken as bycatch and discarded in other fisheries off Argentina, including those for hake and shrimp, and Patagonian bottom trawl fisheries. Females are assumed to be able to breed throughout the entire year. Due to its apparent abundance and probable high reproductive output (for a chondrichthyan) the species is assessed as Least Concern. However, given increasing fisheries pressure across its range, and the recent shift to targeting this species off Buenos Aires Province, careful monitoring needs to be undertaken. Further information is required from Brazil.

Geographic Range [top]

Range Description: Endemic to the Southwest Atlantic from Rio de Janeiro, Brazil (23°S) to Patagonia, Argentina (41°S) (McEachran 1983).
Countries:
Native:
Argentina; Brazil (Rio de Janeiro); Uruguay
FAO Marine Fishing Areas:
Native:
Atlantic – southwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: It is an abundant small skate in Uruguayan and Argentinean coastal waters. San Martín (2003) suggested that the fishing grounds off Puerto Quequén, Argentina are pupping areas for this species.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Off Puerto Quequén the species is found at 36 to 56 m depth and is present during all seasons with a peak in summer. Around 70% of P. bergi sampled in the area are adults. The species did not show sexual differences in size frequency distribution for the whole sample period but some differences were detected seasonally. P. bergi shows a pattern of sexual segregation by season.

San Martín (2003) found that the minimum total length (TL) of free swimming females and males were 29.5 cm and 28.1 cm, respectively, and that the size at 50% of maturity were 44.16 cm TL (580 g) and 45.76 cm TL (584 g) for females and males respectively, which represented 79.1% and 75.6% of the largest females and males measured (55.8 and 60.5 cm TL respectively). This author also concluded that the evidence suggested a continuous reproductive cycle during the year, with a maximum number of females carrying eggcases in spring to summer seasons. 31% of adult females sampled carried one eggcase per oviduct (single oviparity). The number of egg produced per year and the hatching time remains unknown.

This skate feeds mainly on Brachyuran crabs (91.64%, H = 0.11) (San Martín et al. 2003).
Systems: Marine

Threats [top]

Major Threat(s): This skate is commonly caught by the coastal bottom trawlers operating in Buenos Aires Province (Argentina) and has very recently become a target species in this multi-species trawl fishery where previously it was discarded (Tamini 2001). Tamini et al. (2006) found in the Puerto Quequén area that the CPUE of the total batoid catch didn't change in the three years studied. However, species-specific trends are not available, and this fact, combined with the short time frame of the study cannot provide suitable catch trend information for P. bergi. It is also taken as bycatch and discarded in other fisheries off Argentina, including those for hake and shrimp, and Patagonian bottom trawl fisheries.

The increase in fishing pressure along the entire range and over the pupping areas of P. bergi, along with the loss of reproductive areas due to disturbance and destruction of the seabed by the coastal fleet of bottom trawlers could potentially push the species towards the Near Threatened category within the next 3-5 years. Careful monitoring as well as further information from Brazil is required.

Conservation Actions [top]

Conservation Actions: Since 1995, there are a Permitted Maximum Catch (PMC) for coastal skates and rays in Argentina with a peak of 12,000 tonnes in 1997, and a drop to 4,000 tonnes in 2001 and 2002 (Massa et al. 2003). However, as this species was until very recently always discarded, the PMC is not an accurate tool for the conservation of this and other small skates.

Citation: Chiaramonte, G.E. 2004. Psammobatis bergi. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 26 October 2014.
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