Dusky Damselfish, Stegastes adustus
Dusky Damselfish, Stegastes adustus. Fish caught from coastal waters off Islamorada, Florida, April 2018. Length: 8.5 cm (3.3 inches). Catch, photograph and identification courtesy of Marc Eberlein, Grand Rapids, Michigan.
Dusky Damselfish, Stegastes adustus. Fish caught from coastal waters off Pompano Beach Largo, Florida, December 2016. Length: 10 cm (3.9 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
Dusky Damselfish, Stegastes adustus. Fish caught Fish caught off the Channel 5 Bridge (MM 71.4), Florida Keys, Florida, January 2014. Length: 11.6 cm (4.6 inches). Catch, photograph and identification courtesy of Ryan Crutchfield, Tampa, Florida.
Dusky Damselfish, Stegastes adustus. Fish caught from coastal waters off Sugarloaf, Key, Florida, August 2014. Length: 12.2 cm (4.8 inches). Catch, photograph and identification courtesy of Dean Kimberly, Atlanta, Georgia.
Dusky Damselfish, Stegastes adustus. Fish caught from coastal waters off Big Pine Key, Florida, April 2019. Length: 13.1 cm (5.2 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
The Dusky Damselfish have oval robust compressed bodies with a depth that is 44% to 52% of standard length becoming deeper with maturity, thus similar in nature to freshwater bluegills. Adults are uniformly gray-brown in color including their body and fins. Juveniles are similarly colored but with a red-brown cap on the nape of their neck and upper edge of their body, blue spotted lines on their head and upper front of their body, a large black-blue ringed ocellus on the lower part of their dorsal fin and upper body adjacent to their dorsal spines, and a small black spot bordered by blue on their upper caudal fin base. Their head has a small protrusible mouth that opens in the front with a single row of teeth. Their anal fin has 2 spines and 13 to 15 rays; their caudal fin is bluntly forked with bluntly rounded lobes; and their dorsal fin has 12 spines and 14 to 17 rays. Their anal and dorsal fins are short and blunt and do not reach past the caudal fin base. They have 9 or 10 gill rakers on their lower arch. Their body is covered with large rough scales, Their lateral line is incomplete and ends under the edge of their dorsal fin base.The Dusky Damselfish, Stegastes adustus, is a member of in the Damselfish or Pomacentridae Family, and is known in Mexico as jaqueta prieta. 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 Ocean.
The Dusky Damselfish are found in shallow reefs within the surge zone at depths up to 20 m (65 feet) but normally at depths of less than 6 m (20 feet). They reach a maximum of 10.5 cm (4.1 inches) in length. They are diurnal feeders consuming primarily algae, benthic invertebrates and plankton. Reproduction is oviparous with pairing of individuals; eggs are distributed demersal and adhere to the substrate due to their stickiness. The Dusky Damselfish The Downy Blenny 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 Dusky Damselfish is a resident of Mexican waters of the Atlantic Ocean being found throughout the Gulf of Mexico; they are absent from along the east coast of the Yucatán Peninsula in the Caribbean.
The Dusky Damselfish can be confused with a series of other Damselfish including the Beaugregory, Stegastes leucostictus (blue dorsally and yellow ventrally), the Bicolor Damselfish, Stegastes partitus (white on the rear half of body), the Cocoa Damselfish, Stegastes variabilis (yellow caudal and pectoral fins), the Freshwater Gregory, Stegastes otophorous (yellow anal, caudal, dorsal, and pectoral fin tips), the Longfin Damselfish, Stegastes diencaeus (blue line at anal fin margin; blue pectoral fins), the Purple Reeffish, Chromis scotti (blue and gray color), and the Yellowtail Damselfish, Microspathodon chrysurus (blue spotting on upper body).
From a conservation perspective the Dusky Damselfish is currently considered to be of Least Concern with stable, widely distributed populations. They are exceedingly small in stature and of limited interest to most. They are classic nibblers, thus difficult to catch by hook and line.