Tidewater Silverside, Menidia peninsulae
The Tidewater Silverside, Menidia peninsulae, whose common Spanish name is plateadito playero, is a member of the New World Silverside or Atherinopsidae Family, known collectively as charales and pejerreyes in Mexico. Globally, there are seven species in the genus Menidia, of which four are found in Mexican waters of the Atlantic.
The Tidewater Silversides have elongated and compressed bodies. They are translucent and pale silvery in color and have a prominent light yellow-green lateral stripe with a black upper margin. The top of their head is dark and their belly has a yellow tinge. Their head has a short snout, large eyes, a small terminal mouth that opens in the front, and an extendible top jaw. Their anal fin has one spine and 11 to 19 rays; their caudal fin is large and deeply forked; their first dorsal fin has four to six spines and originates before the anus (a key to identification); their second dorsal fin is well separated from the first dorsal fin; and their pelvic fins are closer to the pectoral fins than to the anal fin. They are covered with smooth scales.
The Tidewater Silversides are a schooling pelagic species found at depths up to 20 feet in tranquil shallow intertidal waters, coastal bays, estuaries, and ponds, including brackish waters with salinities in excess of 15 ppt. They reach a maximum length of 18.3 cm (7.2 inches). They are active daytime feeders that form large schools with juveniles consuming plankton; as they mature they change their feeding habits and consume copepods and larvae then larval fish and amphipods. Reproduction is oviparous with large masses of eggs released by females several times per year. Larvae are planktonic.
In Mexican waters the Tidewater Silversides have a very limited distribution being found along the coast of Veracruz in the northwest section of the Gulf of Mexico.
The Tidewater Silverside is similar to, and can be confused with, the Inland Silverside, Menidia beryllina (first dorsal fin inserted directly above anus).
The Tidewater Silversides are of limited interest to most due to their small size, however, they are an important food source for a wide variety of fish, marine mammals, and sea birds. From a conservation perspective, they are common and widespread, thus classified as of Least Concern, however, their population status and trends are unknown.
Tidewater Silverside, Menidia peninsulae. Fish caught from the Alligator Creek, Punta Gordo, Florida, March 2017. Length: 9.5 cm (3.7 inches). Catch and photo courtesy of George Brinkman, Guelph, Ontario, Canada. Identification courtesy of Martini Arostegui, Coral Gables, Florida.