Giant Jawfish or Bigmouth Bastard
Bocón Grande
(Opistognathus rhomaleus)

Giant Jawfish, Opistognathus rhomaleus: The Giant Jawfish or Bigmouth Bastard (its official name) has a light grey tan coloration with numerous black spots covering the head and upper back and along the base of the dorsal fin. Characteristically the sides are devoid of markings.

The Giant Jawfish's bulbous head with enormous mouth with a straight rear jaw that extends well beyond the eyes is truly noteworthy. The Giant Jawfish has a short blunt tail and non-distinct, large, tan pectoral fins. The Giant Jawfish can be confused with the Fine Spotted Jawfish, Opistognathus punctatus (body covered with small spots and large spots and blotches), and the Mexican Jawfish, Opistognathus mexicanus (body covered with brown spots, white lines on anal, caudal and dorsal fins, maximum length 5 inches).

This fish species is reported to reach up to 20 inches in length and is found in the first 60 feet of the water column within sand rubble bottoms.

Distribution in Mexico fishing areas

In Mexican fishing waters, the Giant Jawfish can be found on the Pacific side of Baja California peninsula south from Magdalena Bay, throughout the Sea of Cortez, and around the Revillagigedo Islands. It is absent along the coast of the mainland and around the southern oceanic islands.

The Giant Jawfish is the largest member of the Opistognathidae family of Jawfishes which are curious-looking, small to medium-sized burrowing fish with large bulbous heads, large mouths, big eyes on top and elongated, compressed, tapering bodies. They construct an elaborate burrow network in sandy substrate, that they line with pebbles and shells which undergoes constant renovation. The openings of their burrows are often surrounded by remarkable rings of pebbles or small stones. They are normally are found between 20 and 60 feet deep in the water column and they avoid areas of surge.

The jawfish have long anal and dorsal fin bases, a continuous dorsal fin, and pelvic fins that originate before the pectoral fins. The lateral line is high on the body and stops at midbody. The jawfish are voracious predators feeding on small fish and benthic and planktonic invertebrates. Globally there are 95 known members of the family from three genera of which about one-third have not been described in the literature. Within the Opistognathus genus there are 36 global members of which five are known in Mexican waters.

Giant Jawfish or Bigmouth Bastard fish picture 1

Giant Jawfish, Bigmouth Bastard, Opistognathus punctatus: Caught while fishing with Capt. Pata in panga Salome, in October 2007, in 100-foot deep, 83-degree water, utilizing traditional bottom gear on cut squid bait, 15 miles north of La Playita, San Jose del Cabo, Baja California Sur, Mexico. Size, approximately 12 inches. Description and photo courtesy of John Snow.

Giant Jawfish or Bigmouth Bastard fish picture 2

Giant Jawfish, Bigmouth Bastard, Opistognathus punctatus: Juvenile.  Caught with Capt. Pata in the panga Salome in March 2008, in 100-foot deep, 72-degree water, utilizing traditional bottom gear, 10 miles north of La Playita, San Jose del Cabo, Mexico. Size approximately 10 inches. Descriptiona and photo courtesy of John Snow.

Giant Jawfish or Bigmouth Bastard fish pictureo 3

Giant Jawfish or Bigmouth Bastard fish picture 4

Giant Jawfish, Bigmouth Bastard, Opistognathus punctatus: Caught during a fishing trip in the Midriff Islands south of Bahia de los Angeles, Sea of Cortez, Mexico. Photos courtesy Gene Kira.

Mexico Fishing Home Page < Fish Photo List < Giant Jawfish

Copyright ©