Darkspot Mojarra

Darkspot Mojarra, Eucinostomus entomelas

The Darkspot Mojarra, Eucinostomus entomelas, whose common Spanish name is mojarra mancha negra, is a species in the Mojarra or Gerreidae Family, known collectively as mojarras in Mexico. Globally, there are eleven species in the genus Eucinostomus, and all eleven are found in Mexican waters, seven in the Atlantic and four in the Pacific.

The Darkspot Mojarras have elongated oval bodies with a depth that is 33 to 37% of standard length. Their body is silvery white with juveniles having light tan stripes on the upper side. Their dorsal fin has a black margin. They have a black blotch on their body wall inside the upper corner of their gill covers (after which they are named). Their head has an almost straight upper profile and an enhanced concave lower profile. Their mouth is highly extensible, pointing downward when protruded, and their snout is pointed. They have smooth gill covers. Their anal fin has three spines and seven to nine rays with the second spine being thick and shorter than the third and the same length as the snout. Their caudal fin is deeply forked, their dorsal fin has nine spines and ten rays and is elevated at the front, and their pectoral fins are short and pointed and do not reach the anal fin origin. Their lateral line is curved on the front of the body. Their head and body are covered with rough scales.

The Darkspot Mojarras are a schooling species and reside in shallow coastal areas including mangrove estuaries and fresh water lagoons at depths up to 330 feet. They reach a maximum length of 24.0 cm (9.5 inches). They are a poorly studied species and very limited information is available about their behavioral patterns.

In Mexican waters the Darkspot Mojarras are found in all waters of the Pacific with the exception that they are absent from Guerrero Negro northward along the central and northwest coasts of Baja.

The Darkspot Mojarra can be easily confused with the Pacific Spotfin Mojarra, Eucinostomus dowii (thinner body; no black blotch inside gill cover).

The Darkspot Mojarras are too small and too rare to be of interest to most.

Darkspot Mojarra, Eucinostomus entomelas. Fish caught with a cast net off Palmilla Beach, Baja California Sur, March 2015. Length: 14.9 cm (5.9 inches). Catch courtesy of Mauricio Correa, Cabo Real, Baja California Sur. Fish identification courtesy of H.J. Walker, Jr., Scripps Institute of Oceangraphy, La Jolla, CA.

Darkspot Mojarra, Eucinostomus entomelas. Fish caught from shore at Los Barriles, Baja California Sur, January 2017. Length: 16 cm (6.3 inches). Catch and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.

Darkspot Mojarra, Eucinostomus entomelas. Fish caught with a cast net off the pier at Puerto Adolfo Lopez Mateos, Baja California Sur, April 2016. Length: 16 cm (6.3 inches).

f371-darkspot-mojarra-3Darkspot Mojarra, Eucinostomus entomelas. Fish caught with a cast net off the pier at Puerto Adolfo Lopez Mateos, Baja California Sur, April 2016. Length: 18 cm (7.1 inches).

Darkspot Mojarra, Eucinostomus entomelasFish caught within the coastal waters of Magdalena Bay, Baja California Sur, March 2017. Length: 18 cm (7.1 inches).

Darkspot Mojarra, Eucinostomus entomelas. Fish caught from coastal waters within Bahia de Los Angeles, Baja California, November 2017. Length: 19 cm (7.5 inches). Catch and photo courtesy of Chris Wheaton, Fullerton, CA.

Darkspot Mojarra, Eucinostomus entomelas. Fish caught from shore at Los Barriles, Baja California Sur, January 2017. Length: 20 cm (7.9 inches). Catch and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.