Sciaena callaensis

Sciaena callaensis is a fish of the family Sciaenidae that Hildebrand described in 1946 from just two specimens, both from Callao Bay ^[1]. The World Register of Marine Species (WoRMS) lists it as an accepted name ^[2]. The IUCN Red List classifies it as Critically Endangered ^[3].

Its body is moderately elongate and compressed, with a moderately high back and a rather strongly convex nape ^[1]. The snout is long and conical and juts out ahead of the mouth, which is large, slightly oblique and opens underneath, with the lower jaw shorter than the upper; the lips, maxilla and chin bear papillae ^[1]. In the two specimens of the original description, the dorsal fin has 10 spines followed by 1 spine and 21 to 23 soft rays, the anal fin 2 spines and 9 rays, the pectoral fin 18 rays, and there are 56 to 57 scales in a lateral series ^[1].

The pectoral fin is long, reaching past the tip of the pelvic fin by more than one eye diameter, and the tail fin is distinctly crescent-shaped ^[1]. The old preserved specimens are greyish above with bluish metallic reflections and pale silvery below; dark streaks run along the rows of scales, the pectoral axil is black, and all fins except the pelvics are more or less dusky ^[1].

The type specimen measures 340 mm in total length (270 mm to the base of the tail fin) and the other specimen 230 mm (185 mm) ^[1]. The larger specimen, designated as the type, is number 36934 of the United States National Museum (U.S.N.M.) ^[1].

Similar species

• Sciaena deliciosa: It is very similar and differs mainly in its teeth: in Sciaena callaensis those of the upper jaw form a narrower band with an outer row of large, close-set teeth, and those of the lower jaw sit in 2 main rows, the inner one with enlarged teeth, whereas in Sciaena deliciosa they form broad bands; it also has a straight or slightly concave profile above the eyes, a slightly longer maxilla, somewhat fewer scales and a longer pectoral fin, although the paratype overlaps slightly with Sciaena deliciosa in everything except the teeth and the maxilla ^[1].

When it was described, the species was known only from the type material from Callao Bay, gathered by W. H. Jones in 1884 ^[1]. In the World Register of Marine Species (WoRMS) it is listed as the accepted name of a marine species ^[2].

In Peru it has been recorded as a host of larval stages (metacestodes) of tapeworms of the family Diphyllobothriidae: larvae of Adenocephalus pacificus on the peritoneum and the surface of the stomach, reported by Tantaleán in 1975, and larvae of Diphyllobothrium sp. on the peritoneum, the stomach surface and the body cavity, reported by Escalante in 1983 ^[4].

Its global category on the IUCN Red List is Critically Endangered ^[3].

Its identity calls for caution: Hildebrand himself noted that it is very close to Sciaena deliciosa and that the small specimen overlaps slightly with it in every character except the teeth and the length of the maxilla ^[1]. Even so, WoRMS keeps it as an accepted name ^[2].

Not medical advice. For a sting, a poisoning or an allergy, seek medical care.

Adenocephalus pacificus, one of the tapeworms whose larvae have been found in this species ^[4], is the main cause of diphyllobothriosis in South America, a zoonosis people catch by eating fish ^[5]. A molecular study of plerocercoid larvae in 9 commercially fished species from Peru examined 6999 fish, 6 of them Sciaena callaensis; the combined prevalence across all species was 2.61 % ^[5].

That same 2024 study included it among the 9 commercially important Peruvian fishes that it analysed ^[5].

The literature on the species in Peru points to Callao Bay, where the 2 type specimens were collected in 1884 ^[1]; the records of its parasites, from 1975 and 1983, also come from Peru ^[4].