White Croaker, Genyonemus lineatus
The White Croaker, Genyonemus lineatus, whose common Spanish name is corvineta blanca, is a member of the Croaker or Sciaenidae Family, known collectively as berrugatas or corvinas in Mexico. Globally, this is the only species in the genus Genyonemus and it is found only in Mexican waters of the Pacific.
The White Croakers have elongated, oblong, and compressed bodies. They are silvery with tinges of yellow-bronze dorsally, a small dark spot at the base of their pectoral fin, and white or yellow fins. Their head is oblong and bluntly rounded with a recessed mouth. Adults have no barbels. Their anal fin has two spines and 10 to 12 rays; their caudal fin has a straight margin; their first dorsal fin has 12 to 15 spines and their second dorsal fin has one spine and 18 to 25 rays with a deep notch between both fins; and their pectoral fins are long reaching past the tip of the pelvic fins. They have 27 to 33 gill rakers. Their body is covered with rough scales.
Adult White Croakers are epibenthic and found in loose schools over sandy bottoms in turbid water normally at depths up to 100 feet but they have also been seen at depths up to 660 feet. They reach a maximum length of 41 cm (16 inches) and are dymorphic with females being larger than males. They are known to migrate to deeper waters during the winter. Their diet consists of smaller fish and epibenthic and benthic invertebrates, including polychaetes, clams, shrimp, and crabs. In turn they are preyed upon by numerous larger fish, various marine mammals, and sea birds. Reproduction is oviparous with each female spawning multiple times throughout the year and releasing between 8,000 to 37,000 eggs. They have a lifespan of up to fifteen years.
In Mexican waters the White Croaker has a limited distribution in being found from Magdalena Bay northward along the central and northwest coasts of Baja.
The White Croaker is very similar to the California Corbina, Menticirrhus undulatus (barbel at tip of snout; 10 to 12 dorsal spines) and the Yellowfin Croaker, Umbrina roncador (barbel at tip of snout; ten dorsal spines).
The White Croakers are a mainstay of the year-round California pier fishery and small party vessels and can become pests at times. Commercially they were a very important species in California in the early 19th century, then the fishery declined, resurfaced in the 1970s, and declined again with the implementation of a ban on gill nets from near shore waters. As a food fish, they suffer from a bad reputation being soft, mushy, and parasite-ridden. Commercial fish are used as an ingredient of crab sticks and are normally only retained by subsistence fishermen. They are also used on a limited basis as a live bait targeting California Halibut and Kelp Bass. From a conservation perspective, they are currently considered Near Threatened with landing rates in California decreasing from 150,000 to 30,000 pounds annually over the last 20 years. These declines are attributed to fishing pressure and high levels of pollution including PCBs and DDT from agricultural runoffs. They date to the Late Pliocene Period, 2.6 million years ago and were an important food fish for Native Americans.
White Croaker, Genyonemus lineatus. Fish caught in coastal waters off Long Beach, California, June 2016. Length: 31 cm (12 inches). Catch and photo courtesy of Chris Wheaton, Loreto, Baja California Sur. Identification reconfirmed by H.J. Walker, Scripps Institution of Oceanography, La Jolla, CA.