Beaubrummel, Stegastes flavilatus
The Beaubrummel, Stegastes flavilatus, whose common Spanish name is jaqueta de dos colores, is a species in the family Pomacentridae, the Damselfish, which are known as castañetas and jaquetas in Mexico. This fish is also known as Beaubrummel Major. Globally, there are forty species in the genus Stegastes, of which eleven are found in Mexican waters, seven in the Atlantic and four in the Pacific.
The Beaubrummels have oval compressed bodies with a depth that is 46 – 50% of standard length, thus similar in nature to freshwater bluegills. Adults are light brown to gray-brown in color and have scales with black outlines. Their head has violet markings and the rear portions of their anal, dorsal, pectoral, and pelvic fins are yellowish. Juveniles are bright yellow with a broad blue area on their back and upper part of their head and a black ocellated spot at the junction of their spiny and soft dorsal fins. Their head has a small protrusible mouth that opens in the front with a single row of teeth. Their anal fin has two spines and 12 rays; their caudal fin is bluntly forked; and their dorsal fin is singular and continuous with 12 spines and 14 or 15 rays. They have 11 or 12 gill rakers on their lower arch. Their lateral line is incomplete and ends under the edge of their dorsal fin base. Their body is covered with large rough scales.
The Beaubrummels are found in shallow reefs within the surge zone at depths up to 125 feet but are normally located at depths of less than 50 feet. They reach a maximum length of 16.0 cm (6.3 inches), with this maximum established by a fish I caught. They are diurnal feeders consuming primarily algae, plankton, and benthic invertebrates. They are very aggressive with their feeding habits and when defending their territory. Reproduction is oviparous with pairing of individuals; eggs are distributed demersal and adhere to the substrate due to their stickiness. They are found in all Mexican waters of the Pacific with the exception of north of Guerrero Negro on the northwest coast of Baja and in the northern 30% of the Sea of Cortez.
The Beaubrummel can easily be confused with Cortez Damselfish, Stegastes rectifraenum (uniform brown coloration, 14 to 18 gill rakers on lower arch). It is also somewhat similar to the Bumphead Damselfish, Microspathodon bairdii (large hump on forehead) and the Whitetail Damselfish, Stegastes leucorus (yellow pectoral fin border).
The Beaubrummels are small and of limited interest to most. They are classic nibblers, thus difficult to catch by hook and line.