Rasptail Skate

Rasptail Skate, Raja velezi

The Rasptail Skate, Raja velezi, whose common Spanish name is raya chillona, is a species in the Skate or Rajidae Family, known collectively as rayas in Mexico. Globally, there are thirty-two species in the genus Raja, eight of which are found in Mexican waters, three in the Atlantic and five in the Pacific.

The Rasptail Skakes are shaped as large flattened rhomboid discs that include the head, body, and pectoral fins. The disc has a concave margin that is more pronounced in males and is approximately 20 to 30% wider than it is long. They have a gray-brown coloration with a white underside. They have a pointed head and pointed “wings”. A key to identification are two well-defined ocelli (eye-like spots) which are equally spaced in the center of each pectoral fin (pictured below). Their eyes are on top of the head with spiracles immediately behind. Their nostrils are a little in front of the mouth (which is found on the underside) and the lobes from the nostrils form a curtain between them and the mouth. They have slender tails, which are well demarcated from the body, and these are slightly longer than one-half the disc length. They have two small dorsal fins near the rear of the tail with the caudal fin existing as a fold behind the second dorsal fin. Their pelvic fins have two lobes separated by a notch, with the rear lobe being much larger than the front lobe. The upper surface of the body is covered with small thick spines and there are rows of lethal thorns along the mid-line, located behind the eyes to the first dorsal fin, and two rows along the sides of the tail after which it is named.

The Rasptail Skates are found over sandy bottoms at depths between 100 and 900 feet. They reach a maximum length of 1.0 meter (3 feet 3 inches). They consume shrimp, polychaete worms, and small benthic fish. Reproduction is oviparous with the large eggs laid in black or dark green leathery shells, known as Mermaid’s Purses, which have an oblong outline with a hollow tendril at each corner which is used to attach to marine objects. They are produced in pairs with each case containing up to seven embryos. This species is fairly rare with a limited distribution, thus very little is known about its behavioral patterns. Note: I have reports that this species can be well over a meter in length along the southwest coast of Baja indicative that a new world record is possible.

In Mexican waters the Rasptail Skates have a limited distribution being found throughout the Sea of Cortez, except the extreme northern and southern regions, and along the coast of the mainland south to Guatemala. The fish photographed below documents the presence of the species along the southwest coast of Baja.

Due to the ocelli spots and the two rows of thorns on its tail the Rasptail Skate cannot be confused with any other species.

The Rasptail Skates are taken primarily as a by-catch of deep water shrimp trawls and by shark fishermen on hook and line. They are rare and not considered an important commercial species but are an excellent food fish and are sold predominantly in fish tacos.

Rasptail Skate (1)Rasptail Skate (2)Rasptail Skate (3)

Rasptail Skate, Raja velezi.  Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, June 2007. Total Length: 100 cm (39 inches); Disc Length: 62 cm (24 inches); Disc Width: 76 cm (30 inches); Tail: 38 cm (15 inches).