Lophius



Members of the genus Lophius, also sometimes called monkfish, fishing-frogs, frog-fish and sea-devils, are well known off the coasts of Europe generally, the grotesque shape of its body and its singular habits having attracted the attention of naturalists of all ages. To the North Sea fishermen this fish is known as the "monk," or "monkfish", a name which also belongs to Squatina squatina, the angelshark, a fish allied to the skates. The north European species is L. piscatorius, the Mediterranean species L. budegassa.

Species
There are currently seven recognized extant species in this genus:
 * Lophius americanus Valenciennes, 1837 (American angler)
 * Lophius budegassa Spinola, 1807 (Blackbellied angler)
 * Lophius gastrophysus A. Miranda-Ribeiro, 1915 (Blackfin goosefish)
 * Lophius litulon D. S. Jordan, 1902 (Yellow goosefish)
 * Lophius piscatorius Linnaeus, 1758 (Angler)
 * Lophius vaillanti Regan, 1903 (Shortspine African angler)
 * Lophius vomerinus Valenciennes, 1837 (Devil anglerfish)
 * †Lophius brachysomus Agassiz, 1835 (Monte Bolca, or Eocene anglerfish)

Description
The head is of enormous size, broad, flat and depressed, the remainder of the body appearing merely like an appendage. The wide mouth extends all round the anterior circumference of the head; and both jaws are armed with bands of long pointed teeth, which are inclined inwards, and can be temporarily depressed so as to offer no impediment to an object gliding towards the stomach, while still preventing its escape from the mouth. The pectoral and ventral fins are so articulated as to perform the functions of feet, the fish being enabled "walk" on the bottom of the sea, where it generally hides itself in the sand or amongst seaweed. All round its head and also along the body, the skin bears fringed appendages resembling short fronds of seaweed. These structures, combined with the ability to change the colour of the body to match its surroundings, assists the fish greatly in concealing itself in its lurking places, which are selected for their abundance of prey.

Species of Lophius have three long filaments sprouting from the middle of its head; these are the detached and modified three first spines of the anterior dorsal fin. As with all anglerfish species, the longest filament is the first, which terminates in an irregular growth of flesh, the esca, and is movable in all directions; this modified fin ray is used as a lure to attract other fishes, which the monkfish then seizes with its enormous jaws, devouring them whole. Experiments have shown, however, that whether the prey has been attracted to the lure or not is not strictly relevant, as the action of the jaws is an automatic reflex triggered by contact with the esca.

Monkfish, like most anglerfish are also characterised by an enormously distensible stomach, which allows an individual monkfish to swallow prey fully as large as itself. Monkfish grow to a length of more than 150 cm; specimens of 100 cm are common.

Reproduction
The spawn of this genus is very remarkable. It consists of a thin sheet of transparent gelatinous material 60 - 100 cm wide and 8 - 10 m in length. The eggs in this sheet are in a single layer, each in its own little cavity. The spawn is free in the sea. The larvae are free-swimming and have the pelvic fins with elongated filaments.

Habitat
The East Atlantic species is found all round the coasts of Europe but becomes scarce beyond 60° N. latitude; it occurs also on the coasts of the Cape of Good Hope. The species caught on the North American side of the Atlantic is usually Lophius americanus. A third species (Lophius budegassa), inhabits the Mediterranean, and a fourth (L. setigerus) the coasts of China and Japan.

The black (L. budegassa) and white (L. piscatorius) anglerfish both live in shallow, inshore waters from 800 m to deeper waters (greater than 1000 m). These two species are very similar to one another with only a few distinctions between them. These include; the colour of the peritoneum (black for L. budegassa and white for L. piscatorius) and the number of rays in the second dorsal fin (L. budegassa, 9-10 and L. piscatorius, 11-12). There are also minor differences in their distribution. Black anglerfish tend to have a more southern distribution (Mediterranean and Eastern North Atlantic from the British Isles to Senegal) whereas the white anglerfish are distributed further north, (Mediterranean, Black Sea and Eastern North Atlantic from Barents Sea to the Straits of Gibraltar). Despite these differences, the overall distribution of the black and white anglerfish tend to severely overlap. A map of the distribution of anglerfish in the waters surrounding Europe and North Africa can be found in the external links section. The movements of both species of anglerfish indicate that there is a mixing of both northern and southern species which could have strong implications for the geographical boundaries of the stocks from a management perspective. Both species of Lophius are important because they are commercially valuable species that are usually caught by trawl and gillnetting fleets.

There is concern over the sustainability of monkfish fishing. The method most commonly used to catch monkfish, beam trawling, has been described as damaging to seafloor habitats. In February 2007, the British supermarket chain Asda banned monkfish from their stores.