The Sargassum Fish (Histrio histrio) is a member of the frogfish family (Antennariidae), a group of small, globular fishes with stalked, grasping, limb-like pectoral fins with small gill openings behind the base, a trapdoor-like mouth high on the head, and a "fishing lure" (formed by the first dorsal spine) on the snout. The Sargassum Fish occurs worldwide in tropical and warm-temperate waters. It typically lives in open waters in close association with floating Sargassum Weed (Sargassum natans and S. fluitans), but is frequently blown into nearshore and bay waters during storms. (Boschung et al. 1983; Robins and Ray 1986) Although the Sargassum Fish is capable of swimming quite rapidly, it often crawls through the Sargassum Weed, using its pectoral fins like arms (Rothschild 2004).
The Sargassum Fish (Histrio histrio) occurs worldwide in tropical and warm-temperate waters. In the western Atlantic, it is found from Massachusetts, Bermuda, and the northern Gulf of Mexico and West Indies to southeastern Brazil. (Boschung et al. 1983; Robins and Ray 1986) A small number of specimens have been collected on several occasions off the Kona coast of Hawaii. The discovery of two small juveniles (both about 10 mm SL) here indicates that these specimens are the products of a breeding population rather than migrants from the west. (Pietsch et al. 1992).
The Sargassum Fish has the broadest longitudinal and latitudinal range of any frogfish. Its distribution largely coincides with that of floating Sargassum Weed, with which it is apparently an obligate associate. In the western Atlantic, this species extends from the Gulf of Maine to the mouth of the Rio de la Plata, Uruguay. On the eastern side of the Atlantic, it is apparently quite rare; Pietsch and Grobecker (1987) reported specimens only from the Azores and off West Africa. An old record from Vardo, northern Norway, is likely based on a straggler carried northward by the North Atlantic and Norwegian currents. In the Indian Ocean, the Sargassum Fish is known from the tip of South Africa eastward to India and Sri Lanka, with verified records from the Red Sea, Madagascar, Reunion, and Mauritius. In the western Pacific and on the western margin of the Pacific plate, it occurs from Hokkaido, Japan, to tropical Australia (about as far south as Perth in the west and Sydney in the east), including Taiwan, the Philippines and Moluccas, and the southern coast of Papua New Guinea. There are rare but verified records from Guam, Tonga, New Caledonia, and the North Island of New Zealand. (Pietsch and Grobecker 1987; Pietsch et al. 1992 and references therein)
The Sargassum Fish is unscaled and (unusually for a frogfish) as a consequence has skin that is smooth rather than sandpapery. Its color is variable and changeable, depending on the amount of light and the mood of the fish. It is typically boldly patterned with mahogany brown on a yellowish to olive background, its mottled pattern helping it blend in with the Sargassum Weed in which it lives, but it may be almost black or predominantly yellow with dark spots and blotches. It has many fleshy tabs, the largest on the chin and belly. Its "lure" is a fleshy bulb with filaments attached to a short "pole". The lure is formed by the first dorsal spine; the second and third dorsal spines are large, depressible, and covered with skin bearing fleshy cirri (fingerlike protuberances). (Robins and Ray 1986).
The Sargassum Fish may reach a length of 20 cm, but rarely exceeds about half this size (Robins and Ray 1986).
The only commercial value of the Sargassum Fish is in the aquarium trade (Boschung et al. 1983).
The sargassum fish, anglerfish, or frog fish (Histrio histrio)[3] is a frogfish of the family Antennariidae, the only species in its genus. It lives among Sargassum seaweed which floats in subtropical oceans.[4] The scientific name comes from the Latin histrio meaning a stage player or actor and refers to the fish's feeding behaviour.[5]
Histrio histrio, a strange-looking fish, blends well with its surroundings in its seaweed habitat. It is laterally compressed and its length can reach 20 cm (7.9 in). The colour of the body and the large oral cavity is very variable but is usually mottled and spotted yellow, green, and brown on a paler background, and the fins often have several dark streaks or bands. The fish can change colour rapidly, from light to dark and back again.[3] The body and the fins are covered with many weed-like protrusions, but other than these, the skin is smooth without dermal spines. The dorsal fin has three spines and 11–13 soft rays. The front spine is modified into a slender growth on the upper lip known as an illicium, which is tipped by a fleshy lump, the esca. The junction between the head and body is indistinct because no gill slits are present; the gills open as pores near the base of the pectoral fins.[6] The anal fin has no spines and seven to 13 soft rays. The pelvic fins are large and the pectoral fins have 9-11 rays and are stalked and able to grip objects. The outer rays of the tail fin are simple, but the central rays are forked.[3][7][8]
The sargassum fish has a cosmopolitan distribution in tropical and subtropical seas down to a depth of around 10 m (33 ft). It is found in parts of the Atlantic Ocean and the Indo-Pacific Ocean, where drifting seaweed accumulates. In the western Atlantic, it ranges from the Gulf of Maine south to Uruguay. It has been reported from northern Norway, but that sighting is likely to be as a result of its having been carried along by the North Atlantic Current.[2][3]
The sargassum fish is a voracious ambush predator that is also a cannibal.[3] One individual was dissected and found to have 16 juveniles in its stomach.[8] It stalks its prey among the tangled weeds, relying on its cryptic camouflage for concealment. It can clamber through and cling to the seaweed stalks with its prehensile pectoral fins. It dangles its esca as a fishing lure to attract small fish, shrimp, and other invertebrates. It is able to dart forward to grab its prey by expelling water forcibly through its gill openings. It can expand its mouth to many times its original size in a fraction of a second, drawing prey in via suction, and can swallow prey larger than itself.[8]
It is dioecious. At breeding time, the male courts the female by following her around closely. When ready to spawn, the female ascends rapidly to the surface, where she lays a mass of eggs stuck together by gelatinous mucus. This egg raft adheres to the seaweed, where it is fertilised by the male. On hatching, each larva is surrounded by an integumentary envelope and has a large, rounded head, fully formed fins, and eyes with double notches. As the larva develops into a juvenile, this envelope fuses with the skin.[6]
This fish is preyed on by larger fish and sea birds. To avoid underwater threats, it can leap above the surface onto mats of weed. It can survive for some time out of water.[6]
The sargassum fish, anglerfish, or frog fish (Histrio histrio) is a frogfish of the family Antennariidae, the only species in its genus. It lives among Sargassum seaweed which floats in subtropical oceans. The scientific name comes from the Latin histrio meaning a stage player or actor and refers to the fish's feeding behaviour.
