Pitcher Silverside, Atherinella nepenthe
Pitcher Silverside, Atherinella nepenthe. Fish provided by the commercial bait salesmen of the greater Los Cabos area, Baja California Sur, January 2011. Length: 8.0 cm (3.1 inches).
The Pitcher Silverside, Atherinella nepenthe, is a member of the New World Silverside or Atherinopsidae Family, and is known in Mexico as plateadito marino. Globally, there are thirty-six species in the genus Atherinella, of which seven are found in Mexican waters, two in the Atlantic and five in the Pacific Ocean.
The Pitcher Silverside has an elongated and relatively deep body with a rounded cross section. They are translucent and silvery in color with a silver stripe on their sides that is narrower than the eyes and reaches the caudal fin. Their head has a straight profile with large eyes, a small terminal mouth that opens in the front, and a non-extendible top jaw. Their anal fin has 1 spine and 24 to 30 rays; their caudal fin is forked; their first dorsal fin has 3 to 6 spines and originates over the anal fin origin; their second dorsal fin has 9 to 11 rays and the last dorsal ray is over the last anal fin ray; their pectoral fins reach the pelvic fin tips; and, their pelvic fins are short and do not reach the anus. They are covered with smooth scales.
The Pitcher Silverside is a schooling pelagic species found in shallow intertidal waters, coastal bays, and near coastal reefs from the surface to depths up to 11 m (35 feet). They reach a maximum of 10.0 cm (3.9 inches) in length. They are active daytime feeders that consume algae, small crustaceans, pelagic fish eggs, and pelagic fish larvae. Reproduction is oviparous with large masses of sticky eggs released by females several times per year. These eggs attach themselves to shallow water seaweed via means of long filaments and are then fertilized by males. The larvae are planktonic. The Pitcher Silverside 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 Pitcher Silverside can be confused with the Broadstripe Silverside, Atherinella nesiotes (broad side stripe wider than eye diameter) and the Longfin Silverside, Atherinella eriarcha (side stripe ends in hourglass shape at tail base).
The Pitcher Silverside is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Magdalena Bay, Baja California Sur, southward along the southwest coast of the Baja, from Loreto, Baja California Sur, southward along the southeast coast of the Baja, and along the coast of the mainland from Mazatlán, Sinaloa, southward to Guatemala.
From a conservation perspective the Pitcher Silverside is currently considered to be of Least Concern with stable, widely distributed populations. They are small in stature and of limited interest to most. They are, however, an important food source for a wide variety of fish, marine mammals, and sea birds.