Opaleye, Girella nigricans
Opaleye, Girella nigricans, Juvenile. Fish caught from coastal waters off San Diego, California, August 2018. Length: 10.6 cm (4.2 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.
Opaleye, Girella nigricans. Fish caught off the beach at La Bocana, Baja California Sur, April 2016. Length: 15 cm (5.9 inches). Catch, photograph and identification courtesy of George Brinkman, Guelph, Ontario, Canada.
Opaleye, Girella nigricans. Fish caught from within the Oceanside Harbor, Oceanside, California, January 2020. Length: 17.5 cm (6.9 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.
Opaleye, Girella nigricans. Fish caught from within the Oceanside Harbor, Oceanside, California, January 2020. Length: 17.5 cm (6.9 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.
Opaleye, Girella nigricans. Underwater photograph taken in coastal waters off San Diego, California, August 2018. Fish enjoying a French Fry. Photograph and identification courtesy of Ben Cantrell, San Diego, California.
The Opaleye, Girella nigricans, is a member of the Sea Chub or Kyphosidae Family, that is also known as the California Opaleye and in Mexico as chopa verde. Globally, there are eighteen species in the genus Girella, of which two are found in Mexican waters, both in the Pacific Ocean.
The Opaleye has an elongated oval compressed body that have a depth that is 38% to 42% of standard length. They are olive-green to gray-green with 2 pale spots on their upper back below the mid-dorsal fin that are absent in mature adults. Most have a white bar across their snout between the eyes. They have bright blue-green eyes for which they are named. Their coloring transitions to a uniform dark brown upon death. They have a short blunt head and a small mouth with thick lips opening at the front that is equipped with small incisiform teeth set horizontally in the mouth with flattened three-pointed tips and a curved hockey-stick shape. Their anal fin has 3 spines and 10 to 13 rays; their caudal fin is concave; their dorsal fin is continuous with 12 to 14 spines folding down into a scaly grove and 12 to 15 rays; and, their pectoral and pelvic fins are relatively short. With the exception of the caudal fin, all their fins are blunt to rounded. Their body is covered with small, thick, and rough scales.
The Opaleye is found in large schools, normally demersal, within rocky areas with an abundance of algae growth at depths up to 32 m (105 feet); they will occasionally enter estuaries. Juveniles are pelagic and found near the surface often within floating debris. They reach a maximum length of 66 cm (2 feet 2 inches). As of January 1, 2024, the International Game Fish Association world record stood at 2.27 kg (5 lbs 0 oz) with the fish caught in coastal waters off Monterey, California, December 2023. They are an eurythermal species being able to tolerate water temperatures as low as 8oC (46oF) and as high as 35oC (95oF). They are diurnal omnivores grazing on algae and preying on invertebrates. The Opaleye 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 Opaleye is a resident of Mexican waters of the Pacific Ocean but have a limited range being found along the entire west coast of Baja and in isolated populations throughout the Sea of Cortez. They are absent from Mazatlán, Sinaloa southward along the central and southwest coasts of the mainland.
The Opaleye is most likely confused with the Halfmoon, Medialuna californiensis (black blotch at top of gill cover), the Gulf Opaleye, Girella simplicidens (pointed anal and dorsal fins; 3 to 4 white spots; bright blue eyes), and the Zebraperch, Hermosilla azurea (8 faint bars on sides; black spot at pectoral fin base).
From a conservation perspective the Opaleye is currently considered to be of Least Concern with stable, widely distributed populations. They are considered to be marginal table fare and only retained by subsistence fishermen.