Eastern Pacific Black Ghostshark, Hydrolagus melanophasma
Eastern Pacific Black Ghostshark, Hydrolagus melanophasma, male. Fish collected alive off the surface with a bait net by Pesces Sportfishing 19 km (12 miles) south of Cabo San Lucas, Baja California Sur, May 2009. Length: 90 cm (2 feet 11 inches). A female was also collected by the same fleet in the same location, April 2010.
The Eastern Pacific Black Ghostshark, Hydrolagus melanophasma, that is also known as the Black Ratfish and in Mexico as quimera negra is a species in the family the Shortnose Chimaeridae or Chimaera Family, known collectively as quimeras in Mexico. The species is very newly discovered with only a handful of fish being collected and introduced to science in 2009. Globally, there are forty-eight members of the family that have been placed in three genera, and five species in the genus Hydrolagus, of which four are found in Mexican waters, all in the Pacific Ocean.
The Eastern Pacific Black Ghostsharks have compressed rounded elongated bodies that taper into a filamentous tail, which is almost one-half the length of the fish. They are uniformly black with a lighter band across their snout. Their head is very large and “rabbit-like” with a short rounded broad duckbill-shaped snout, large eyes, and large nostrils. Their mouth is on the underside with two pairs of plates on the top jaw and one pair on the bottom jaw. They do not have an anal fin; their caudal fin is elongated with 2 equal sized lobes and a whip-like rear filament; their first dorsal fin is large and triangular in shape with the front edge having a prominent venomous spine that is slightly taller than the fin itself; the second dorsal fin has a long base with a low undulating profile of uniform height; their pectoral fins are well developed, broad and triangle-shaped and reach past the pelvic fin origin; and, their pelvic fins are also broad and triangle-shaped. They are scaleless with smooth skin. They have prominent lateral line canals. Males have a spiny and club-shaped process located on their head (pictured above).
The Eastern Pacific Black Ghostshark is found over and within muddy and rocky bottom habitats at depths between 30 m (100 feet) and 1,720 m (5,640 feet). They reach a maximum of 1.2 m (3 feet 11 inches) in lenght with the fish photographed above establishing this record. They are feeble swimmers and locate prey primarily through electroreception and smell consuming clams, crabs, small benthic fish, shrimps, and polychaete worms. In turn they are preyed upon by larger sharks. Reproduction is oviparous with females releasing spoon-shaped egg cases every ten to fourteen days over a period of several months. The Eastern Pacific Black Ghostshark 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 Eastern Pacific Black Ghostshark is a resident of the Pacific but has a limited range in being found only along the west coast of Baja.
The Eastern Pacific Black Ghostshark can be confused with the smaller cold water Spotted Ratfish, Hydrolagus colliei (maximum length of 1 m / 3 feet 3 inches); covered with white spots).
From a conservation perspective the Eastern Pacific Black Ghostshark has not been formally evaluated. They are exceedingly rare, of limited value to humans, but of great interest to the scientific community.