Redtail Surfperch, Amphistichus rhodoterus
Redtail Surfperch, Amphistichus rhodoterus. Fish off the beach at Astoria, Oregon, September 2013. Length: 28 cm (11 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
Redtail Surfperch, Amphistichus rhodoterus. Fish off the beach at Bookings, Oregon, October 2008. Length: 30 cm (12 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
The Redtail Surfperch, Amphistichus rhodoterus, is a member of the Surfperch or Embiotocidae Family, that are also known as porgie and the rosy surf fish and in Mexico as mojarra cola roja. Globally, there are three species in the genus Amphistichus, and all three are found in Mexican waters of the Pacific Ocean and all three are found within this website.
The Redtail Surfperch have highly compressed deep oval body with a depth that is 48% to 52% of standard length and an upper head profile that is nearly straight. They are predominantly a whitish-silver color with a brassy cast with green mottling and 9 to 11 narrow vertical bars on their sides that posteriorly are broken and staggered along the lateral line. Their anal, caudal and dorsal fins and red or pink. As they mature the males develop a distinctive permanent shortening of some anal fins rays as they mature that appear as a notch in profile. The juveniles are more colored than the adults with the bars on the sides transitioning to olive-red brown with maturity. Their head has a small upturned mouth. Their anal fin has 3 spines and 28 to 31 rays; their caudal fin is moderately forked; their dorsal fin is continuous with 9 or 10 spines and 25 to 28 soft rays; and their pectoral fins are of moderate size. They have 16 to 22 gill rakers. Their lateral line is high on the body and extends from the pectoral fins to the caudal fin. Their body is covered with small scales.
The Redtail Surfperch is a common schooling species that are common along sandy ocean beaches, jetties, and shorelines year-round from the intertidal zone to depths up to 7 m (24 feet). They enter estuaries during the spring. They are known to form mixed schools with Pacific Sand Lance, Ammodytes hexapterus, Pacific Staghorn Sculpin, Leptocottus armatus, Shiner Perch, Cymatogaster aggregate, and Silver Surfperch, Hyperprosopon ellipticum. They reach a maximum of 41 cm (16 inches) in length and 2.1 kg (4.5 lbs) in weight with females growing faster and becoming larger than males. They have lifespans of fourteen years. As of January 1, 2023, the International Game Fish Association world record stood at 0.57 kg (1 lb 4 oz) with the fish caught in coastal waters off Orick, California in August 2013. They primarily consume small crabs, shrimp and small fishes and other crustaceans including mussels and marine worms. In turn they are heavily preyed upon by humans, harbor seals and sea lions. Reproduction is viviparous with each female giving birth to between three and forty live young in annual cycles and is iteroparous, with each female reproducing multiple times during her life. They have gestation periods of eight months with females migrating many miles up into estuaries in the spring to give birth.
The Redtail Surfperch is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found only from Punta Baja in the greater El Rosario area of Baja California, northward along the northwest coasts of Baja.
The Redtail Surfperch is most likely confused with the Barred Surfperch, Amphistichus argenteus (pale fins; longer dorsal rays than dorsal spines), the Calico Surfperch, Amphistichus rhodoterus (longer dorsal rays than dorsal spines), and the Silver Surfperch, Hyperprosopon ellipticum (pink caudal fin).
From a conservation perspective the Redtail Surfperch has not been formally evaluated. They are a popular fish with recreational anglers and heavily pursued off the beach, piers, jetties and in estuaries in the Pacific Northwest of the United States. In some parts of their range they are also fished commercial. They are also utilized by the aquarium trade at a modest level. They have been dated to 100,000 years ago.