Black Axillary Mojarra, Eugerres axillaris
The Black Axillary Mojarra, Eugerres axillaris, whose common Spanish name is mojarra malacapala, is a species in the Mojarra or Gerreidae Family, known as collectively mojarras in Mexico. Globally, there are only seven species in the genus Eugerres, six of which are found in Mexican waters, three in the Atlantic and three in the Pacific.
The Black Axillary Mojarra has a rhomboidal, deep compressed body that has a depth that is 48 – 52% of standard length. The bodies are silvery in color being darker on the back with thin dark lines along the scale rows on the upper half of the body. They have dark fins and the spiny dorsal has a thin black margin and the inside of the pectoral fin base is dark (for which they are named). The head has a steep straight upper and a concave lower profile, the mouth ends under the front edge of the pupil and the mouth is highly extensible, pointing downward when protruded. The head and body are covered with rough scales. The anal fin has 3 spines and 8 rays and the second spine is long and thick; the caudal fin is forked; the dorsal fin has 9 spines and 9 or 10 rays and is elevated at the front; the pectoral fins are long reaching past the anal fin origin. They have 14 to 16 lower gill rakers and the gill covers are serrated.
The Black Axillary Mojarra reside in shallow coastal areas and lagoons at depths up to 100 feet. They have a maximum length of 25 cm (9.8 inches). They are a poorly studied species and as such very limited information is available about their behavioral patterns.
In Mexican waters the Black Axillary Mojarra have a limited distribution being found from Magdalena Bay southward along the southwest coast of Baja, in the southern half of the Sea of Cortez and along the coast of the mainland south to Guatemala.
The Black Axillary Mojarra can be confused with the Shortnose Mojarra, Diapterus brevirostris (yellow anal and pelvic fins), the Streaked Mojarra, Eugerres lineatus (pectoral fin not reaching anal origin; 11 to 12 gill rakers) and the Striped Mojarra, Eugerres plumieri (Atlantic Ocean, straight head profile; lacks black spot at pectoral base).
The Black Axillary Mojarra, although small, is sold commercially and although small is stature is deemed to be an excellent food fish.
Black Axillary Mojarra, Eugerres axillaris. Fish caught within the coastal waters of Magdalena Bay, Baja California Sur, April 2016. Length: 20 cm (7.9 inches).
Black Axillary Mojarra, Eugerres axillaris. Fish caught with a cast net off a pier at Puerto Adolfo Lopez Mateos, Baja California Sur, December 2017. Length: 21 cm (8.3 inches). Catch courtesy of Ruben Duran, Puerto Adolfo Lopez Mateos, Baja California Sur. Photo and identification courtesy of Brad Murakami, Surrey, British Columbia, Canada.