Lumptail searobin

Prionotus stephanophrys is a bottom-dwelling fish of the family Triglidae, order Perciformes ^[1]. It was described in 1881 from a single specimen from California ^[2]. The studies we cite place it on the continental shelf of the eastern Pacific, and one of them used fish landed in Peru ^[3]. Its global IUCN Red List category is Least Concern ^[4].

Lockington described the species as new in 1881 from a single specimen, bought in the San Francisco market in October 1880 and caught off Point Reyes ^[2]. The author explains that the species name refers to a serrated, crest-like ridge over each eye ^[2].

In the original description the body is slaty gray above and white on the lower third, and the front dorsal fin carries a black spot between spines 4 and 5 ^[2]. The second dorsal and the tail fin have 3 rows of black spots, and the pectoral fin is black with whitish clouding ^[2].

The snout profile is concave, and the head bears strong spines on the gill cover and the preopercle, in addition to the ridge over each eye ^[2]. Each pectoral fin has 3 very slender free filaments, and the author counts 11 rays in the anal fin of the specimen described ^[2]. Lockington compared it with Prionotus miles from the Galapagos and said it resembles that species most, but with much longer pectoral fins and different colouring ^[2].

According to the authors who study it in Ecuador and Peru, it lives in the eastern Pacific, from southern California to southern Peru (Ilo) or, in another paper, to Chile ^[5],[3]. It is a bottom fish of the continental shelf, with records down to about 220-240 m ^[5],[3].

In the Gulf of Guayaquil it was taken by bottom trawl between 64 and 207 m, in waters where the hake Merluccius gayi is also fished ^[5].

In a sample of 622 individuals from the Ecuadorian trawl fishery, total length ranged from 21 to 36 cm, with a mean of 27.73 cm in females and 26.78 cm in males ^[5]. There were 1.5 females per male, and the mean size at maturity was estimated at 20.22 cm, a value the authors say agrees with what had been found earlier in Peru ^[5]. In 40 fish from Piura and Tumbes the mean total length was 25.16 cm in females and 23.45 cm in males ^[3].

The gonadosomatic index was highest in February 2017 (5.30) and January 2018 (3.46), and lowest in May 2017 (0.88) and August 2018 (0.52), so reproductive activity peaks in the austral summer ^[5]. The species lays eggs, and in Peru spawning has been placed in summer ^[3].

It feeds mostly on crustaceans, and in a Peruvian study reported by the Ecuadorian authors euphausiids made up about 65 % of the diet ^[5]. The rest is fish, annelids and molluscs ^[3].

It shares habitat with the hake and both feed on euphausiids. In Ecuador weight did not increase in the same proportion as length (negative allometric growth), which the authors attribute possibly to food supply and competition with the hake, in a gulf with fewer euphausiids ^[5].

The fish studied in Lima harboured 19 taxa of metazoan parasites, all new records for Peru ^[3]. The most frequent were the monogenean Orbocotyle elmernoblei, in 30 % of the fish, and the nematode of the Anisakis simplex complex, in 22.5 % ^[3].

The IUCN classifies it globally as Least Concern ^[4]. It is not a target species: in Ecuador it comes up as bycatch of trawling and its commercial value is low ^[5].

The authors of that study point out that almost all the individuals caught were above the size at maturity (only 3.86 % were below it) and that the largest catch of females coincides with the peak of reproductive intensity, and they regard studying the species as a priority ^[5].

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

Of the 40 fish examined in Lima, 9 carried larvae of the Anisakis simplex complex and 1 a Phocanema larva ^[3]. The authors consider that the larvae of both genera are potential zoonotic agents, above all if the fish is eaten raw or undercooked, for example in ceviche ^[3].

In Peru it has been used for frozen products such as surimi, according to the authors of the parasite study ^[3]. In Ecuador, by contrast, it is hardly used: it is landed mostly for fishmeal or discarded at sea ^[5].

The fish in the Lima study were caught in 2023 and 2024 with artisanal gear, such as purse seine and hooks, in the ports of Paita (Piura) and Pizarro (Tumbes), and were taken to the Villa María del Triunfo fishing terminal ^[3]. It is a bottom fish of the shelf, and the literature we cite studies it in landings, not underwater ^[3].