Surf croaker

Umbrina xanti is a bony fish of the family Sciaenidae, the drums and croakers, described by Gill in 1862 and accepted as a valid species ^[1]. It lives over shallow sandy bottoms in the eastern Pacific, from the Gulf of California to Peru ^[2]. In Peru it is called "polla", "polla rayada", "verrugato polla", "cachicato" or "cebra" ^[2]. It is caught with nets in Mexico and is not threatened globally ^[3],[4].

The genus name Umbrina derives from Latin umbra (shadow), in the sense of a phantom; it refers to the speed of the fish's movements ^[2].

The body is oblong and compressed, of moderate depth, with an arched back and a prominent snout ^[2]. The mouth is small and inferior, the lower jaw is enclosed by the upper one, and the chin carries a stiff barbel ^[2].

The second dorsal fin is short, bearing 20 soft rays, and each pectoral has 19 rays ^[2]. The colour is dark and silvery, with no stripes on the flanks, the fins are dark, and the prolonged first pelvic ray is white ^[2]. Usual total length is 22 cm and the recorded maximum is 40 cm ^[2]; Mexican catches included fish between 17.9 and 42.3 cm ^[3].

The species occurs in the eastern Pacific, from the Gulf of California to Peru ^[2]. A Mexican study places it from Baja California to northern Peru ^[3].

It is a demersal fish found between 0 and 35 m depth over sandy bottoms, and juveniles also turn up in shore pools ^[2]. It can enter coastal lagoons and estuaries ^[3].

At Bahía de Navidad (Jalisco, Mexico), 1202 fish caught in gill nets between 1998 and 2008 were examined; 80 % measured between 28 and 32 cm total length ^[3]. Females outnumbered males, at a ratio of 1 to 0.88 ^[3].

Mean length at maturity was 27.37 cm in females and 28.78 cm in males, so more than half of the catch had already spawned at least once ^[3]. The gonadosomatic index of females peaked in March (4.75) and April (4.62), and that of males in April ^[3]; mature ovaries were recorded from January to June ^[3].

Oocytes within one ovary mature asynchronously, which points to multiple spawnings; 7 stages of oocyte development were distinguished in females ^[3].

It feeds on fishes, crustaceans and bivalves ^[2]. At Tumbes, the gill monogenean Euryhaliotrema sagmatum, a flatworm parasite, was recorded from a specimen ^[5].

The IUCN Red List classifies Umbrina xanti as Least Concern (LC) globally, based on the 2020 assessment ^[4].

In the Mexican Pacific it is a commercially important species for artisanal fisheries, and in Jalisco it is frequently caught ^[3]. In the Bahía de Navidad catches, fish of 28 to 32 cm predominated ^[3]. FishBase lists it as a commercial fishery resource and as harmless to people ^[2].

The Peruvian literature consulted records the species at Tumbes, in the far north of the country: the monogenean checklist published in 2024 cites there, from the gills of a marine specimen of Umbrina xanti, its parasite Euryhaliotrema sagmatum ^[5]. The checklist says nothing about access to the place or about where to watch the fish ^[5].