Cortez Halibut, Paralichthys aestuarius
The Cortez Halibut, Paralichthys aestuarius, whose common Spanish name is lenguado de Cortés, is a member of the Sand Flounder or Paralichthyidae Family, known collectively as lenguados areneros in Mexico. Globally, there are twenty one species in the genus Paralichthys, six of which are found in Mexican waters, three in the Atlantic and three in the Pacific. All family members are left-eyed fish and have an arched lateral line.
The Cortez Halibuts have elongated oval deep bodies with a depth that is 42 to 45% of standard length. They are left-eyed flat fish with a small percentage being right-eyed fish. Their eyed-side is pale chocolate brown with mixed light and dark spotting that is more predominant at the margins of their disk. Their fins have the same color as the body. Their blind side is off-white to tan. They have a short pointed head and parallel eyes with a flat space in between. They have one row of teeth on both jaws with large canines in the front. They have 57 to 67 anal rays and 72 to 85 dorsal rays. Their dorsal fin begins over the upper eye. Their caudal fin is small, short, and wide with straight margins. They have 24 to 31 gill rakers. Both sides of their body are covered with smooth scales. The lateral ine is arched and extends onto their head and branches toward their top eye and below their lower eye.
The Cortez Halibuts are bottom dwellers found near structures over and within sandy and muddy bottoms at depths up to 180 feet. They are also known to enter brackish waters. They reach a maximum length of 58 cm (23 inches). They are opportunistic and well-camouflaged ambush predators that lie in wait half-submerged on the ocean floor. They consume crustaceans, anchovies, grunions, sardines, and other small fish. They are a relatively obscure and poorly studied species with very little known about their behavioral patterns.
In Mexican waters the Cortez Halibuts have a limited distribution being found from Guerrero Negro southward along the central and southwest coasts of Baja, throughout the Sea of Cortez, and along the coast of the mainland south to Acapulco.
The Cortez Halibut is most likely confused with the California Halibut, Paralichthys californicus (doubly concave caudal fin) and the Dappled Flounder, Paralichthys woolmani (less than 20 gill rakers).
The Cortez Halibuts are a quality food fish but not abundant. They are caught primarily as a by-catch of deep water shrimp trawlers.
Cortez Halibut, Paralichthys aestuarius, right eyed. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Length: 31 cm (12 inches). Photo courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.