Angular Angel Shark aka Spiny Angel Shark. Information and Pictures of Squatina guggenheim

Angular Angelshark

Angular angelshark

View all available Angular Angel Shark Pictures in the Elasmodiver Shark Picture Database

Common Names:

Angular angelshark, spiny angel shark, hidden angelshark.

Latin Name:

Squatina guggenheim. Possibly synonymous with Squatina punctata.

Family:

Squatinidae

Identification:

Row of short spines/thorns (modified denticles) along midline of back. Spines may be indistinct and flattened in females. Dorsum covered in a fine network of tiny dark irregular spots that form an overall grey/brown appearance. A few scattered small to large dark spots on torso, pectoral and pelvic fins.

Forehead (between widely spaced eyes) concave. Terminal mouth with unfringed nasal barbells.

Angular angelshark head and mouth detail

Size:

Maximum recorded size 95cm. Size a maturity 70-80cm. Size at birth 25-30cm.

Habitat:

Continental shelf at a depth of 10-150m. Mostly 10-80m on mixed sand and rock substrates.

Abundance and distribution:

The angular angel shark is restricted to the east coast of South America from Rio de Janeiro in Brazil to Northern Patagonia in Argentina.

Diet:

Mostly bony fishes supplemented by crustaceans and mollusks.

Behavior:

Nocturnal. An ambush predator; the angular angelshark remains motionless for long periods waiting for a fish to swim within striking distance.

Reproduction:

Ovoviviparous with one functional ovary. Litter size 2-10 but usually 5-6. Angular angel sharks mature after 4-5 years.

Conservation Status:

Listed as ENDANGERED by the IUCN. The nocturnal habits of angel sharks render them vulnerable to bottom gillnets, and increases in captures during the 1990s are attributed to the introduction of this gear on the shelf and slope off southern Brazil at that time. Gillnets were reported as six times more effective at catching angel sharks than trawling alone (Vooren and Klippel 2005).
Gravid females of S. guggenheim 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.
Fishery landing statistics of "angel shark" in southern Brazil refer to S. guggenheim, S. occulta and S. argentina combined. The term "angel shark" in the present assessment refers to this assemblage of species. These three species occur on the continental shelf with S. argentina also occurring on the upper slope. Annual catches of angel shark from the continental shelf peaked at about 2,000t in 1986-1989 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). While S. occulta and S. argentina have been significant bycatch species in the trawl and gillnet fishery for monkfish Lophius gastrophysus at the shelf edge and uppermost slope, S.guggenheim occurs shallower than that fishery.
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 S. guggenheim 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, in 1973, Cousseau 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 1998-2003 (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).'

Citation: Chiaramonte, G. & Vooren, C.M. 2007. Squatina guggenheim. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>.

Photographs:

Mar Del Plata, Argentina.

Similar species:

The Angular Angelshark shares its range with the hidden angel shark S.occulta which has no spines along its midline, less obvious and smaller spots with no dark edges. It also shares its range with the Argentine angelshark S.argentina which has a purplish-brown dorsum with many scattered dark brown spots. The deeper dwelling S.argentina is restricted to depths between 51-320m.

Reaction to divers:

Remains motionless relying on camouflage to avoid detection unless very closely approached. The angular angel shark will sometimes tolerate a diver gently wafting the sand off of its back to get a better look. If the shark bolts, it generally does not swim far. It may settle again within view if followed at a distance.

Diving logistics:

Juan Carlos Mattioli from Intersub Buceo in Mar Del Plata may be able to help you find this species. Angular angelsharks inhabit an offshore bank that rises to approximately 15-20m about ten miles from shore.

However, diving in Mar Del Plata and elsewhere in Argentina is difficult because of the weather which is frequently windy offshore. For best results head to Argentina in the summer from December to March and be prepared for long waits if the wind is strong.

HOME LINKS TAXONOMY UNDER THREAT BOOKS CONTACT