Roughbar Frogfish

Fowlerichthys avalonis is a frogfish (family Antennariidae, order Lophiiformes) of the eastern Pacific, described in 1907 by Jordan and Starks, which Sielfeld (2010) still treated as Antennarius avalonis ^[1], and now accepted in the genus Fowlerichthys ^[2]. It lives on rocky bottoms, from the intertidal zone down to about 300 m, and reaches 33 cm in total length ^[3]. Its known range runs from southern California to Peru, with one record farther south, in northern Chile ^[1].

The two specimens studied in northern Chile (collected on 15 February 2000), of 264 and 193 mm total length, had a large, short head that was deeper than long, a long and slender caudal peduncle, a lower jaw that barely projects, and small teeth in narrow bands on the jaws, the vomer and the palatines ^[1]. The soft dorsal fin had 12 to 13 rays, the anal fin 8 and the pectorals 13 branched rays; 21 to 23 very distinct lateral-line pores were counted between the eyes and the base of the tail ^[1]. As in the rest of the family, the gill opening is very small and sits below the base of the pectoral fin, and the first dorsal spine ends in a bait ^[4].

The first dorsal spine is very slender, 66 % to 76 % as long as the second, and is inserted behind the groove of the maxilla; it carries a simple esca made of short appendages set vertically, whose length does not exceed 40 % of that of the illicium ^[1]. The second spine is joined to the head, and the third to the back, by a reduced membrane ^[1].

The body is brown with brown and black blotches; the belly and the upper side of the pectoral fin bear many diffuse dark blotches, and the fins are dark with irregular brown spots ^[1]. At the base of the dorsal fin there is a black blotch ringed by a narrow orange band, and both specimens also showed two pale blotches on the flanks, in line with it ^[1].

Similar species

• Antennarius sanguineus: This is the frogfish that Hildebrand first recorded in Peru; its skin is covered with prickles, nearly all of them forked, and the bait on its first spine is made up mostly of folds of skin ^[4], whereas in Fowlerichthys avalonis the esca is a series of short vertical appendages ^[1].
• Antennarius pauciradiatus: An illicium shorter than the second spine leads to this species in the key, but it is set apart by the number of branched pectoral rays, the absence of appendages on the second spine and the pocket for the esca ^[1].

It is known from the eastern Pacific, from Santa Catalina Island in southern California to Peru, and includes the Galápagos Islands and Cocos Island ^[1].

The first record for the continental coast of northern Chile was published in 2010: two specimens taken in a rocky sublittoral area at Iquique, at 20°12' S, which extended the known southern limit by about 8° of latitude from the 12° S of Peru ^[1].

Adults live on rocky ground, including the intertidal zone, and are also found on sand and mud; the depth range is 0 to 300 m and usually 0 to 95 m ^[3].

It reaches 33 cm in total length, although 15 cm is the usual size ^[3]. The 264 and 193 mm fish from Iquique were large compared with the much smaller ones of earlier studies, and their author puts the differences in illicium length down to that difference in size ^[1].

The species is oviparous; young fish feed mainly on crustaceans, while larger individuals eat more fish, sometimes fish of their own size ^[3].

Because its diet shifts from crustaceans to fish, FishBase estimates a trophic level of 4.0, typical of a consumer of fish and crustaceans ^[3].

Sielfeld considers its presence at Iquique, at 20°12' S, to be probably a non-permanent southern limit, one that would fluctuate with the faunal displacements tied to El Niño events, and writes that the specimens were taken during the 1997/98 event; the collection date given in the same paper is 15 February 2000, so that coincidence is unclear ^[1].

The IUCN classifies it globally as Least Concern, in its 2008 assessment ^[5]. FishBase gives a low vulnerability to fishing, 18 out of 100, and a high resilience, and treats it as harmless to people ^[3].