Apron Ray, Apron Numbfish.
A large electric ray with a teardrop-shaped body and a short, rounded snout. Anterior margins of disc weakly convex. Pectoral fin apices broadly rounded. Eyes weakly protruding, very small; smaller than spiracles. Spiracles oval-shaped and smooth edged; without papillae on posterior margin. Nasal curtain wider than long with a pronounced central lobe. Nostrils small and circular.
Pelvic fins broad and long with rounded apices. Tail moderately wide at base, with well developed lateral keels. Dorsal fins closely spaced, large, and angled backwards, with broadly to narrowly rounded apices and broadly convex posterior margins. First dorsal origin over pelvic fin posterior margin. Caudal fin large, dorsal margin mildly convex, posterior/ventral margin broadly rounded.
Dorsum light to dark brown, pinkish grey, or olive brown, occasionally with darker blotches. Lateral line pores conspicuously white. Disc margin, lateral keels, and posterior margins of dorsal and caudal fins may also be white. Ventrum white, occasionally with darker blotches around electric organs.
Maximum length ~55cm. Size at birth 8-9cm.
Temperate seas. Benthic on soft substrates, often around rocky reefs. From 10 to 181m.
Southeast Pacific and southwest Atlantic. Found from Peru, southward around Cape Horn and northward to Rio Grande do Sul in Brazil.
The Apron Numbfish is captured in demersal trawl and inshore artisanal gillnet fisheries. In Chile, it is occasionally captured in the deep-water crustacean trawl and the inshore artisanal gillnet fishery and is discarded (Acuña et al. 2002, Hernández et al. 2010). In Buenos Aires, Argentina, this species is the most frequently captured elasmobranch in inshore trawl catches targeting gastropods, flatfishes, and the Narrownose Smoothhound (Mustelus schmitti), but is always discarded and is likely to have high survivorship (Tamini et al. 2006, Chiaramonte et al. 2011). In the Argentine and Uruguayan Common Fishery Zone, this species is discarded and survival post- capture is still unknown (Massa et al. 2004, Tamini et al. 2006, Estalles et al. 2011).
Dulvy, N.K., Acuña, E., Bustamante, C., Cuevas, J.M., Herman, K. & Velez-Zuazo, X. 2020. Discopyge tschudii. The IUCN Red List of Threatened Species 2020: e.T44993A2999889. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T44993A2999889.en. Downloaded on 30 May 2021.
Aplacental viviparous. Litter size 1-12, usually 4-5.
Feeds mostly on polychaete worms and amphipods.
Segregates by sex.
Reaction to divers
Easy to approach. Usually remains completely motionless but may try to deliver a shock and then relocate when threatened.
Aparently more common in Argentina but I have only seen this ray in Zapallar Bay (about 2 hours north of Santiago, Chile) but other divers report sightings along the central coast so it is obviously quite widespread and relatively easy to find in the Pacific.
Sightings are usually on sand or mixed rocks and sand so if you would like to see this ray, shore-diving in sandy bays close to Santiago would be an ideal place to start. Most bays are exposed to surge but the bay at Zapallar is protected from some of the swells. Park your vehicle on the public beach in the centre of the bay and swim to the left (south) before submerging. This is also a good spot to locate ‘Pinta roca’ aka. Redspotted catsharks.
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Castello’s Apron Ray Distinguishable by deep concavities in anterior margins of pectoral fins.