Bairdiella, Bairdiella icistia
Bairdiella, Bairdiella icistia, Juvenile. Fish caught with a cast net off the pier in Puerto Adolfo Lopez Mateos, Baja California Sur, October 2016. Length: 2.5 cm (1.0 inch).
Bairdiella, Bairdiella icistia, Juvenile. Fish caught with a cast net off the pier in Puerto Adolfo Lopez Mateos, Baja California Sur, August 2018. Length: 5.0 cm (2.0 inches). Note the significant change in fin coloration and enhanced lateral line versus the fish photographed immediately above.
Bairdiella, Bairdiella icistia. Fish caught within Magdalena Bay, Baja California Sur, July 2016. Length: 22.0 cm (8.7 inches).
The Bairdiella, Bairdiella icistia, is a member of the Croaker or Sciaenidae Family, and is known in Mexico as ronco roncacho. Globally, there are five species in the genus Bairdiella, and all five are found in Mexican waters, two in the Atlantic and three in the Pacific Ocean.
The Bairdiella has an elongated, oblong, and compressed body. They are silvery with yellowish fins and a dark spot at the base of their pectoral fins. Their upper lip and the tip of their lower jaw are dusky. Their head is narrow with a short blunt snout. They have a large slightly oblique mouth that opens in the front, reaches the middle of the eyes, and is equipped with conical teeth in narrow rows. They have no barbels. Their anal fin has 2 spines and 7 or 8 rays with the second anal spine being long and similar in length to the first anal ray; their caudal fin is straight to slightly convex and does not reach the caudal fin; their first dorsal fin has 10 to 12 spines; their second dorsal fin has 1 or 2 spines and 24 to 28 rays; and, their pectoral fin is short and extends to the second dorsal fin. Their gill covers have 8 or 9 spines including 2 to 4 spines at an angle. They have 23 to 27 gill rakers. They are covered with rough scales. Their lateral line extends to the center of the caudal fin.
The Bairdiella is a demersal species that is found in inshore waters including estuaries at depths up to 18 m (60 feet). They reach a maximum of 30 cm (12 inches) in length. They feed on crustacean larvae, shrimp, and small fish. They are preyed upon by a variety of larger fish and various sea mammals. The Bairdiella 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 Bairdiella is a resident of all waters of Mexican waters of the Pacific with the exception that that it is absent from Punta Abreojos, Baja California Sur, northward along the central and northwest coasts of Baja.
The Bairdiella is can be confused with the Armed Croaker, Bairdiella armata (21 to 23 dorsal rays; rounded caudal fin) and the Swordspine Croaker, Bairdiella ensifera (second anal spine reaches caudal fin; 24 to 26 dorsal rays).
From a conservation perspective the Bairdiella is currently considered to be of Least Concern with stable, widely distributed populations. They are a small in stature and of limited interest to most. They were introduced to the Salton Sea in Southern California in 1950; although they thrived for several years they were eventually extirpated due to the erosion of water quality caused by increased levels of salt and related pollution. They were also introduced to New Mexico waters but suffered the same fate.