Habitat and Ecology
Aplacental yolksac viviparous with one functional ovary. Reproduction begins in both males and females at about 70 to 80 cm TL (Cousseau 1973, Vooren and Silva 1991, Compagno in prep). Maximum size is 91 to 92 cm TL (Compagno in prep., Silva 1996). Number of embryos per litter is 3 to 8 (Vooren and Silva 1991, Compagno in prep). The breeding cycle of the female lasts at least two years. S. punctata migrates in spring to shallow coastal waters where the females give birth and where small juveniles occur all year round (Vooren and Silva 1991).
Life History and Behavior
IUCN Red List Assessment
Red List Category
Red List Criteria
Squatina punctata is endemic to the Southwest Atlantic from Rio de Janeiro, Brazil (24°S) through Uruguay to northern Patagonia, Argentina (43°S) on the shelf at 10 to 150 m depth. The species' low reproductive potential (litter size of 3 to 9 and triennial female breeding cycle) together with its vulnerability to both trawl and gillnet gear makes it highly susceptible to population depletion. Angel sharks are heavily fished in southern Brazil and significant declines have been documented there. An angel shark bottom gillnet fishery commenced around 1990 and at present large amounts of angel shark is caught this way. Research trawl surveys of the outer shelf in the years 1986/87 and 2001/02 confirmed that in southern Brazil the abundance of angel shark had decreased by ~85%, which was attributed to recruitment overfishing. In Argentina, landings of angel shark have shown a negative trend since 1998 after the catch peaked. Catches there consist apparently almost entirely of S. guggenheim. Given that intensive fisheries occur throughout the species' range, together with its vulnerability to depletion, and the evidence that off Brazil, fishing has reduced previously abundant stocks of angel sharks to 15% of original levels, S. punctata is assessed as Endangered. In the first instance, the resolution of taxonomic and nomenclatural issues, in order to accurately define the occurrence, distribution and declines of individual species, is paramount to the conservation of Southwest Atlantic angel sharks.
Gravid angel shark females have been observed to abort embryos easily upon capture, further reducing the reproductive capacity (Vooren and Klippel 2005). A low rate of dispersal between populations also makes them especially prone to local depletion and means that recolonisation will be extremely low. Furthermore, pupping and nursery areas in Brazil occur in shallow inshore waters at depths of
Fishery landing statistics of "angel shark" in southern Brazil refer to Squatina species combined. Annual catches of angel shark from the continental shelf peaked at about 2,000 t in 1986 to 1989 and again in 1993, and then decreased to 900 t in 2003. Angel shark CPUE by otter trawl and pair trawl on the continental shelf decreased by about 85% from 1984 to 2002 (Miranda and Vooren 2003, CEPERG 2003, GEP/CTTMar 2003, Vooren and Klippel 2005).
Additionally, an angel shark bottom gillnet fishery on the outer shelf commenced around 1990 and at present large amounts of angel shark are caught this way (Miranda and Vooren 2003). Research trawl surveys of the outer shelf in the years 1986/87 and 2001/02 confirmed that in southern Brazil the abundance of angel shark has decreased to 15% of its original level and this is attributed to recruitment overfishing primarily due to the bottom gillnet fishery (Vooren and Lamónaca 2002, Vooren and Klippel 2005).
In Argentina, the shark bycatch from gillnet and bottom trawl fleets targeting species such as school shark, croakers and flatfishes is poorly known. However, Cousseau (1973), based on Nani and Gonzalez Alberdi (1966), estimated Squatina as 6% of the total weight of the catches of the coastal bottom trawling fleet. The predominant size in these catches was about 70 to 80 cm TL; small sizes (25 to 45 cm TL) were uncommon. Cousseau (1973), based on García Cabrejos and Malaret (1969) calculated the total landings of angel shark in Mar del Plata harbour in 1964 to be 1,074 MT and 2,355 MT in 1965. Otero et al. (1982) considered the angel sharks to be species with a low concentration on the Buenos Aires coast, with an annual biomass for 1981/2 estimated at 4,050 tons. However, in 1991 as much as 4,167 MT were taken, and 4,281 MT in 1996. Chiaramonte (1998) stated that the angel sharks were the second most important fish landed by the gillnet fleet of Puerto Quequen. Total captures of angel sharks in Argentina oscillated around 1,000 MT between 1979 and 1984 then increased to maximums of over 4,000 MT in the 1990s. Catches consist almost entirely of S. guggenheim. Peaks were reached in 1997 and 1998, before landings dropped in 2002 to 2,000 MT, rising again in 2003 to 3,550 MT (Massa et al. 2004). Thus there has been an overall negative trend in landings during the period 1998 to 2003 (Massa et al. 2004). Furthermore, Vooren and Klippel (2005) (citing Massa and Hozbor 2003) suggested a 58% decline in the CPUE of angel shark in the coastal bottom trawl fleet.
In Uruguay there is little direct fishing for angel sharks, but they are taken as bycatch in industrial and artisanal fisheries. The estimated capture has been 300 to 400 MT per year since 1997. There are no statistics by species, but largest captures probably correspond to S. guggenheim and S. argentina (A. Domingo pers. comm).
Vooren and Klippel (2005) recommend the protection of the coastal nursery grounds in southern Brazil (waters south of 32°30'S) from fishing as an essential measure for the conservation of this species.
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