Blunthead Triggerfish

Blunthead Triggerfish, Pseudobalistes naufragium

Blunthead Triggerfish, Pseudobalistes naufragium. Fish caught from coastal waters off Mazatlán, Sinaloa, March 2016. Length: 36 cm (14 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Blunthead Triggerfish, Pseudobalistes naufragium. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2009. Length: 63 cm (2 feet 1 inch).

Blunthead Triggerfish, Pseudobalistes naufragium. Underwater photograph taken in Zihuantanejo Bay, Guerrero, March 2018. Photograph courtesy of Ron Woheau, Zihuantanejo.

Blunthead Triggerfish, Pseudobalistes naufragium. Underwater photograph taken in coastal waters of the greater Los Cabos area, Baja California Sur, May 2018. Photograph courtesy of Bob Hillis, Ivins, Utah.

Blunthead Triggerfish, Pseudobalistes naufragium. Underwater photographs taken in coastal waters off Puerto Vallarta, Jalisco, July 2023. Photograph courtesy of Kevin Erwin, Seattle, Washington.

The Blunthead Triggerfish, Pseudobalistes naufragium, is a member of the Triggerfish or Balistidae Family, that is known in Mexico as cochito bota. They are also known in Central America as “Chancos,” There are only three global members of the genus Pseudobalistes, one of which is found in Mexican waters, this fish from the Pacific Ocean.

The Blunthead Triggerfish have robust, compressed, oblong, deep bodies that are 49 to 53% of standard length. They are pale blue to brownish gray with several alternating light and dark wide bars on their sides; these bars fade quickly after collection. Most have a visible white gill opening. In mature adults, the head has a blunt profile with disproportionately small beady eyes, a small mouth that opens at the front, powerful jaws with eight heavy human-like teeth on the upper and lower jaws, and a deep groove in front of the eyes. Their anal and second dorsal fins are of similar size and location and are exceedingly long in younger fish; their caudal fin varies from fish to fish being doubly concave with pointed lobes to rounded with small lobes; their dorsal fin has three spines, the first of which can be locked erect, the second being one-half the size of the first, and the third being closer to the first dorsal spine than to the second dorsal fin; and the pelvic fins are minute. They have thick leathery skin.

The Blunthead Triggerfish are found in and around rocky coral reefs and close to boulders adjacent to sand at depths up to 100 m (330 feet) of the water column. They reach a maximum of 1.0 cm (3 feet 3 inches) in length and 9.0 kg (19 lbs 13 oz) in weight. As of January 1, 2024, the International Game Fish Association world record stood at 6.6 kg (14 lbs 9 oz) with the fish caught in coastal waters off La Paz, Baja California Sur, in August 2005. The Blunthead Triggerfish 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.

The Blunthead Triggerfish is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Magdalena Bay, Baja California Sur southward along the southwest coast of the Baja, in the southern two thirds of the Sea of Cortez, and along the coast of the mainland south to Guatemala.

The Blunthead Triggerfish can be confused with the Rough Triggerfish, Canthidermis maculata (body depth 43-45% of standard length; long anal and dorsal fins) and the Finescale Triggerfish, Balistes polylepis (body depth 55-57% of standard length; shorter anal and dorsal fins).

From a conservation perspective the Blunthead Triggerfish is currently considered to be of Least Concern with stable, widely distributed populations. They are exceedingly rare and therefore of limited interest. Based on my extensive experiences with their smaller brothers the Blunthead Triggerfish might be THE toughest foe in the sea pound for pound.