Silver Jenny

Silver Jenny, Eucinostomus gula

Silver Jenny, Eucinostomus gula. Fish caught from coastal waters off Key Largo, Florida, November 2020. Length: 15.2 cm (6.0 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

Silver Jenny, Eucinostomus gula. Fish caught from within the Phil Foster Park, Riviera Beach, Florida, June 2023. Length: 11.5 cm (4.5 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

Silver Jenny, Eucinostomus gula. Fish caught from coastal waters off the Silver Palm Park, Boca Raton, Florida, January 2017. Length: 16.5 cm (6.5 inches). Catch, photograph, and identification courtesy of George Brinkman, Guelph, Ontario, Canada.

The Silver Jenny, Eucinostomus gula, is a member of the Mojarra or Gerreidae Family, and is known in Mexico as mojarra española. Globally, there are eleven species in the genus Eucinostomus, all of which are found in Mexican waters with seven in the Atlantic and four in the Pacific Ocean.

The Silver Jenny has an oval, compressed, and fusiform body with a depth that is 38% to 42% of standard length. They are silvery with light pigmentation on their snout. Their head has as strongly concave lower profile, a pointed snout, and a highly extensible mouth that points downward. Their anal fin has 3 spines, the second of which is the longest, and 7 rays; their caudal fin is deeply forked; and, their dorsal fin has 9 spines and 10 rays. They have 7 or 8 gill rakers on the lower arch. Their body is covered with large rough scales.

The Silver Jenny is an abundant schooling species found seasonally in shallow coastal waters over muddy bottoms in mangrove-lined lagoons and creeks at depths up to 53 m (175 feet) and in waters that range in temperature between 11oC (52oF) and 28oC (82oF). Juveniles are found in seagrass beds. They are also known to enter freshwater. They reach a maximum of 23.0 cm (9.1 inches) in length. They are known to make seasonal migrations to warmer offshore waters during cooler months for wintering and hibernation and return to coastal waters in the spring for breeding. They are benthic feeders that probe the bottom with their protrusible mouth and consume bivalves, crustaceans, detritus and ostracods. The Silver Jenny 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 Silver Jenny is found in all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the Caribbean. They are very abundant on a seasonal basis within the Ria Lagartos National Wildlife Refuge on the northern tip of the Yucatán Peninsula.

The Silver Jenny is fairly similar to a series of other mojarras including the Mottled Mojarra, Eucinostomus lefroyi, the Slender Mojarra, Eucinostomus jonesii, the Spotfin Mojarra, Eucinostomus argenteus, and the Tidewater Mojarra, Eucinostomus harengulus, but these all have significantly thinner bodies. The Yellowfin Mojarra, Gerres cinereus has a similar body depth but has seven or eight dark bars on its sides.

From a conservation perspective the Silver Jenny is currently considered to be of Least Concern with stable, widely distributed populations, however, the loss of estuaries and seagrass beds from coastal environments is of concern in the long-term. They are small in stature and of limited interest to most. They are marketed fresh in some South American countries but are not in high demand. They are used on a limited basis as live bait.

NOTE.  There are eighteen members of the Mojarra or Gerreidae Family currently Included in this website, ten are from Mexican waters of the Pacific and eight from the Atlantic. They are all very similar in appearance and difficult to identify.  As an aide to this challenge I have assembled a Mojarra Body Depth Chart that presents these seventeen mojarras from thin bodied to deep bodied which is useful in identification work. In addition, I have also assembled a Mojarra Maximum Length Chart which I have also helpful in the identification work for these eighteen mojarras. Both charts can be found at the end of the Mojarra Family Page.