Whitenose Shark, Nasolamia velox
Whitenose Shark, Nasolamia velox. Fish caught in coastal waters north of Puerto Los Cabos, Baja California Sur, June 2007. Length: 1.07 m (3 feet 6 inches). Identification courtesy of Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama.
The Whitenose Shark, Nasolamia velox, is a member of the Requiem Shark or Carcharhinidae Family, and is known in Mexico as tiburón coyotito. Globally, this fish is the only species in the genus Nasolamia and it is found in Mexican oceanic waters of the Pacific Ocean.
The Whitenose Shark has a slender body with a very long conical snout. They are uniformly brownish-gray with metallic hues dorsally and transition to white ventrally. Their second dorsal fin has a dusky tip. Their anal fin is slightly larger than their second dorsal fin and has a deeply notched posterior margin; their caudal fin is asymmetrical and curved with an upper lobe that is notched under the tip and a large lower lobe; their first dorsal fin originates over the free tips at the rear of the pectoral fins; their second dorsal fin is smaller than the first with a height that is about one-third the height of the first dorsal fin and originates over the anal fin; and, their pectoral fins are broad, triangular, and slightly falcate and originate over the third gill slit. Their head is very narrow and conical with a pointed snout this is much longer that the width of the mouth. They have large eyes with a small vertical pupil. Their nostrils are very large, transverse, oval, and close set and are located midway between the tip of the snout and the front of the mouth. Their upper jaw has 27 to 30 strongly oblique cusps with a strong notch on the outer margins, finely serrated edges, and overlapping bases. Their lower jaw has 25 to 27 slender, narrow, finely serrated, non-protruding teeth set it rows. They lack the traditional ridge between the dorsal fins or keels on the caudal peduncle that are found in other similar sharks. They have 5 gill slits with the last two being over the pectoral fins.
The Whitenose Shark is uncommon and found demersal both inshore and offshore over the continental shelf at depths between 24 m (80 feet) and 183 m (600 feet). They reach a maximum of 1.65 m (5 feet 5 inches) in length. As of January 1, 2023, the International Game Fish Association world record stood at 167 kg (369 lbs) with the fish caught in coastal waters off the Bahamas in January 1998. They feed on small fish such as anchovies and invertebrates such as crabs. Reproduction is viviparous with litter sizes between 5 and 6 with the pups being 50 cm (20 inches) to 55 cm (22 inches) in length. The Whitenose Shark is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
In Mexican waters the Whitenose Shark is found in all waters of the Pacific with the exception that they are absent from Guerrero Negro, Baja California, northward along the central and northwest coasts of Baja. They are infrequent visitors to the Baja and only found during warm water episodes; they are known to congregate at certain times of the year in coastal waters off Puerto Madero, Chiapas.
The Whitenose Shark is most likely confused with the Blue Shark, Prionace glauca (dorsal fin posterior originating well behind free tips of pectoral fins) and the Pacific Sharpnose Shark, Rhizoprionodon longurio (pronounced labial furrows; more widely spaced nostrils; second dorsal fin originating well behind anal fin origin).
From a conservation perspective the Whitenose Shark is currently considered to be Data Deficient due to their rarity. Of concern is the inshore fishing pressure, human destructive trawling practices, water pollution, and coastal sedimentation that all have an adverse effect on their coastal nursery grounds. They are not currently protected by any form of management measures. They are caught on a limited basis as a by-catch of artisanal fishermen utilizing longlines and gill nets. They are used as food for local consumption and in fish meal. Their fins are exported to Asia. There have been no documented attacks on humans by Whitenose Sharks.