Acapulco Damselfish, Stegastes acapulcoensis
The Acapulco Damselfish, Stegastes acapulcoensis, whose common Spanish name is jaqueta acapulqueña, is a species in the Damselfish or Pomacentridae Family, known collectively as castañetas and jaquetas in Mexico. Globally, there are forty species in the genus Stegastes, eleven of which are found in Mexican waters, seven in the Atlantic and four in the Pacific.
The Acapulco Damselfish have oval compressed bodies that has a depth that is 42 to 46% of standard length, thus similar in nature to freshwater bluegills. Adults are gray-brown and lighter on the head and first half of the body. Their scales have black margins and their pectoral fins have a prominent white spot at their base. Juveniles are bright blue with a prominent ocellus at the base of their soft dorsal fin and an ocellated black spot on the dorsal edge of their caudal peduncle. Their head has a small protrusible mouth that opens in the front with a single row of long and closely set teeth. Their gill covers are serrated. Their anal fin has 2 spines and 13 rays; their caudal fin is bluntly forked; their dorsal fin is singular and continuous with 12 spines and 15 or 16 rays; and their pectoral fins have 20 to 23 rays. They have 17 to 21 long and close-set gill rakers on their lower arch. Their lateral line is incomplete and ends under the edge of the dorsal fin base. Their body is covered with large rough scales.
The Acapulco Damselfish are found in shallow rocky areas within the surge zone at depths up to 55 feet. They reach a maximum length of 18.0 cm (7.1 inches). They are diurnal feeders consuming primarily algae, plankton, and benthic invertebrates. They are very aggressive when feeding or when when defending their territory. Reproduction is oviparous with pairing of individuals; sticky eggs are distributed demersal and adhere to the substrate.
The Acapulco Damselfish have a limited and poorly documented range being found along the east coast of Baja from Loreto southward to the East Cape, along the southwest coast of the Baja into the Pacific (as documented by the fish photographed below), and from Mazatlán southward along the coast of the mainland to Guatemala.
The Acapulco Damselfish is most likely confused with the Cortez Damselfish, Stegastes rectifraenum (uniform reddish brown color) and the Giant Damselfish, Microspathodon dorsalis (extended, elongated, and pointed anal and dorsal fins).
The Acapulco Damselfish are small, poorly documented, and poorly studied, therefore of limited interest to most. They are classic nibblers, and difficult to catch via hook and line.
Acapulco Damselfish, Stegastes acapulcoensis. Fish caught from coastal waters off Mazatlán, Sinaloa, October 2017. Length: 12.5 cm (5.0 inches). Catch, photo and identification courtesy of George Brinkman, Guelph, Ontario, Canada.
Acapulco Damselfish, Stegastes acapulcoensis. Fish caught from coastal waters off Puerto Escondido, Oaxaca, October 2009. Length: 15.0 cm (5.9 inches). Catch, photo and identification courtesy of Josh Leisen (lifelistfishing.com), Gaylord, MI.
Acapulco Damselfish, Stegastes acapulcoensis. Underwater photograph taken in coastal waters of Bahia Tenacatita, Jalisco. Length: 17 cm (6.7 inches). Photo and identification courtesy of Jeff Cross, Albuquerque, NM.