Pacific Spiny Dogfish, Squalus suckleyi
The Pacific Spiny Dogfish, Squalus suckleyi, whose common Spanish name is cazón espinoso común, is a species in the Dogfish Sharks or Squalidae Family, known collectively as cazónes aguijones in Mexico. Globally, there are only nine species in the genus Squalus, three of which are found in Mexican waters, two in the Atlantic and one in the Pacific.
The Pacific Spiny Dogfish have slender cylindrical bodies. They are gray dorsally and white ventrally and usually have conspicuous white spots on their sides. Their head has a narrow pointed snout, eyes midway between the tip of the snout and the first of five gill slits, a short nasal flap with the inner corners of the nostrils being closer to the snout tip than to the mouth, and modest sized spiracles just behind the eyes. The teeth on their upper and lower jaws are low, blade-like, and of similar size with strongly oblique tips. They do not have anal fins. Their caudal fin has a pair of keels and an angular notch separating the two lobes, but does not have a notched lower lobe. They have two dorsal fins, the first originating behind the pectoral fins; both fins have a single spine with the second dorsal spine being longer than the first dorsal spine. Their pectoral fins are narrow and sickle-shaped. Their skin is covered with small denticles that have three-points.
The Pacific Spiny Dogfish are found both near the surface in bays and estuaries and on the bottom in the open ocean at depths up to 4,500 feet. They reach a maximum length of 1.6 meters (just over 5 feet). They prefer waters between 7oC (45oF) and 15oC (59oF) and will make longitudinal and depth migrations to follow this temperature preference. Reproduction is ovoviviparous with offspring developing from eggs hatched within the female’s body and released alive into the ocean without placental attachment. They are a poorly studied and rather obscure species.
In Mexican waters the Pacific Spiny Dogfish have a limited distribution being found only along the west coast of the Baja.
The Pacific Spiny Dogfish cannot be confused with any other species due to the unique configuration of the spines of its two dorsal fins.
The Pacific Spiny Dogfish are considered edible but are in very low demand. Larger individuals are reported to contain high levels of mercury. From a conservation perspective, they have not been evaluated and their long-term viability is unknown.
Pacific Spiny Dogfish, Squalus suckleyi. Fish caught from coastal waters off Redondo Beach, California, November 2016. Length: 1.12 meters (3 feet 8 inches). Catch, photo, and identification courtesy of Ben Cantrell, Peoria, IL.