White croaker (Genyonemus lineatus)

Also known as: croaker, king croaker, kingfish, king-fish, roncador, tomcod
Synonyms: Leiostomus lineatus
  
French: Courbine Blanche, Maigre Argenté
Spanish: Corvineta Blanca, Roncador Blanco
KingdomAnimalia
PhylumChordata
ClassActinopterygii
OrderPerciformes
FamilySciaenidae
GenusGenyonemus (1)
SizeMaximum length: 41 cm (2)

The white croaker is classified as Near Threatened (NT) on the IUCN Red List (1).

The white croaker (Genyonemus lineatus) is a small, rather plain-looking fish with an elongated body, a rounded, oblong head (4) and a protruding upper jaw (3). The upperside of the white croaker is yellow-brown and the underside is silver with faint, wavy lines (4) (6). The fins are yellow or white (3) (4) (6) and there is usually a black spot at the base of the pectoral fins and black edges to the caudal fin (3) (5). A deep groove separates the two dorsal fins (4).

The underside of the white croaker’s chin has small, whisker-like barbels, which are more conspicuous in some individuals than in others and are different from the larger, single barbels seen in species in the Genyonemus genus (5).

The white croaker gains its common name from the distinctive croaking noise which is made when muscles contract around its swim bladder, amplifying the sound. This noise can travel over long distances (4). 

The range of the white croaker extends from British Colombia in Canada south through the United States to Baja California and Mexico (1) (2) (3) (4) (5) (6). Populations of this species are generally less abundant in areas north of California (2) (3) (4) (5). 

A marine species, the white croaker inhabits areas close to the sandy seabed in both inshore and offshore areas where the current is calm, including shallow bays and lagoons. It is generally found at depths between 3 and 30 metres, although on rare occasions it may be found to depths of 180 metres (4). 

The white croaker is a schooling fish (3) (5), and is often found swimming with queenfishes (Scomberoides spp.) and other species in shallow water (5). This fish consumes a wide variety of fish, squid, shrimp, crabs, molluscs and worms (2) (4).

An oviparous species, the white croaker spawns multiple clutches of eggs in the open ocean (2). Little other information is available on the biology of this species. 

The white croaker is of very little commercial value in the fishing industry, although it is under threat from fishing as it is still frequently caught as bycatch (1) (4). Living in inshore polluted waters also poses a threat to this species, as the pollutants can negatively affect its reproductive behaviour and increase the probability of liver disease (1). 

There are not currently any specific conservation measures known to be in place for the white croaker. It has been advised that this species should not be eaten when caught from certain areas, due to it carrying trace amounts of certain harmful pollutants (5). Monitoring of its populations and the levels of harvest are needed to provide effective conservation measures for the white croaker (1). 

More information on the white croaker:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
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  1.  IUCN Red List (April, 2012)
    http://www.iucnredlist.org/
  2. FishBase - White croaker (April, 2012)
    http://fishbase.org/summary/Genyonemus-lineatus.html
  3. Eschmeyer, W.N., Herald, O.W., Mammann, H. and Gnagy, J. (1983) A Field Guide to Pacific Coast Fishes of North America. Houghton Mifflin Company, New York.
  4. Schultz, K. (2004) Ken Schultz’s Guide to Saltwater Fish. John Wiley and Sons, Inc, New Jersey.
  5. Goodson, G. (1988) Fishes of the Pacific Coast: Alaska to Peru, including the Gulf of California and the Galapagos Islands. Stanford University Press, Stanford.
  6. Miller, D.J. and Lea, R.N. (1976) Guide to the Coastal Marine Fishes of California. ANR Publications, California.