Tete sea catfish

Ariopsis seemanni (Günther, 1864) is a sea catfish of the family Ariidae, accepted in WoRMS, that lives in coastal and brackish waters of the American Pacific; a study of its sounds describes it as common from Mexico to Peru ^[1],[2]. It reaches about 44.4 cm total length and sits at a middle trophic level ^[3].

Males brood the eggs in the mouth ^[3]. It is fished for food and, in Colombia, juveniles of 5 to 10 cm are sold as aquarium fish; the IUCN lists it as Least Concern (LC) ^[4],[5].

Among the sea catfishes of the eastern Pacific it differs from Ariopsis guatemalensis by its large eye, 36% to 63% of the distance between the eyes, against a small eye of about 25% in Ariopsis guatemalensis ^[6].

The lower tooth plate of Ariopsis seemanni is thin and split into two sections, whereas Ariopsis guatemalensis has its palate teeth in four patches and three pairs of barbels ^[6]. A species account is no substitute for a regional taxonomic key: the 2017 revision of the genus is the reference FishBase points to for the species ^[3].

FishBase gives the species a latitude range of 24°N to 5°S ^[3]. A study of its sounds describes it as common in coastal marine and brackish waters of Central and South America, from Mexico to Peru ^[2].

It is demersal and can live in marine, brackish and fresh water, ascending medium and large rivers to at least 25 m above sea level ^[3]. In the Mexican Pacific it was caught as bycatch with seine nets in a shallow estuarine zone less than 3 m deep ^[6].

The recorded maximum is 44.4 cm total length and 912.3 g, and the estimated trophic level is 3.6 ^[3]. In a trial in Colombia, the wild females used averaged 263.6 g and 25.3 cm total length ^[4].

Males incubate the eggs in the oral cavity ^[3]. The oocytes of the females averaged 13.2 mm in diameter and, in the 15 females with oocytes in final maturation, the mean was about 30 per female, an apparently low fecundity that the authors relate to the care of eggs and larvae in the male's mouth ^[4].

The ovaries held oocytes at different stages of development, and in a captive hormone trial none of the 24 pairs spawned spontaneously ^[4]. Juveniles of about 7.2 cm reared on diets of 28% to 53% protein survived at over 75%, close to 95% on the 45% diet and to 75% on the 53% one ^[7].

Individuals emit short constant-frequency sounds, with a median duration of 19.5 ms and a fundamental frequency of 148.3 to 249.8 Hz at 24.5 °C ^[2].

In the laboratory, 5 fish chose the arm of a Y-maze with a loudspeaker in 67% of the trials, which suggests the calls may help hold the group together; the authors consider it highly unlikely that they serve for acoustic obstacle detection ^[2].

The IUCN globally classifies Ariopsis seemanni as Least Concern (LC) ^[5]. FishBase rates its vulnerability to fishing as low to moderate, with a score of 34 out of 100 ^[3].

In Colombia, the authors of a breeding trial note heavy fishing pressure over the last two decades on juveniles of 5 to 10 cm for the aquarium trade ^[4].

It is a commercial fish sold fresh or salted ^[3]. On the Colombian Pacific, adults longer than 25 cm are traditionally eaten in coastal communities ^[4].

Juveniles of 5 to 10 cm are sold as ornamental fish at home and abroad, acclimated to fresh water, and this trade is more profitable than selling adults for food ^[4],[7].