Yellow snake eel

Ophichthus zophochir is a snake-eel of the family Ophichthidae, order Anguilliformes, described by Jordan and Gilbert in 1882 ^[1]. In Peru it is recorded under the names anguila amarilla and culebra marina ^[2]. Its global IUCN Red List category is Least Concern ^[3].

It is a bottom-dwelling species of the continental margin of the tropical eastern Pacific, from Eureka in California to Paita in the northern Peruvian transition zone; at Huacho and Callao in central Peru it turns up only occasionally, perhaps because of El Niño events. The authors doubt that the northeastern Pacific records reflect a self-sustaining population, and note that larvae of ophichthid eels have never been caught north of Punta San Juanico in Baja California (26°N) ^[4].

It has not been recorded from the Galápagos or from any other island area ^[4]. A study of shorefish larvae likewise places it along the continental margin from California to Peru, and lists a maximum depth of 100 m for the species ^[5].

Like other eels, it passes through a larval stage called a leptocephalus. In March 1985, 8 larvae of this species were caught over the Galápagos Rift, with standard lengths between 93.5 and 161.0 mm; they were identified by their DNA barcode ^[5].

In an analysis of the mitochondrial COI gene from 177 samples of rocky-reef fishes in northern Peru, individuals of Ophichthus zophochir showed a divergence of 2.19 %, above 2 %. When compared with sequences from elsewhere in the eastern Pacific, the authors separated 4 lineages, three from the tropical eastern Pacific and one from the northeastern Pacific, and suggest they could represent more than one species, something other studies must confirm ^[4].

The larvae of most shorefishes stay close to shore, but eel leptocephali, including those of shelf-dwelling ophichthids, are a known exception because they can turn up far out at sea. The catch of 1338 shorefish larvae over the Galápagos Rift, at a single site on the equator, included larvae of 77 species or more, many of continental origin ^[5].

For the two Ophichthus zophochir larvae found in the open ocean, the authors of the genetic study consider that currents may have carried them from Baja California, since the adult has not been recorded on islands ^[4].

The IUCN places the species in the global category Least Concern ^[3]. The distinct genetic lineages found in 2025 do not yet change its taxonomic treatment; the authors indicate that other markers and approaches are needed to confirm whether they are species complexes ^[4].

The Peruvian specimens of this species known from the literature come from scuba sampling on rocky reefs of northern Peru, under a permit from the Ministry of Production, at Isla Foca, along the stretch between Cabo Blanco and Los Órganos and at Punta Sal. In total 226 fishes of 82 species were collected, and the study does not say at which of those places each specimen was found, nor does it document sightings by divers ^[4].