Lophius

Members of the genus Lophius, also sometimes called monkfish, fishing-frogs, frog-fish, and sea-devils, are various species of lophiid anglerfishes found in the Atlantic and Indian Oceans. Lophius is known as the "monk" or "monkfish" to the North Sea fishermen, a name which also belongs to Squatina squatina, the angelshark, a type of shark. The North European species is Lophius piscatorius, and the Mediterranean species is Lophius budegassa.

Species
The seven rec­og­nized ex­tant species in this genus are:

Fossils

 * †Lophius brachysomus Agassiz, 1835 (Monte Bolca, or Eocene anglerfish)

Description
The head is large, broad, flat, and de­pressed, with the re­main­der of the body ap­pear­ing merely like an ap­pendage. The wide mouth ex­tends all around 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 to walk on the bot­tom of the sea, where it gen­er­ally hides it­self in the sand or amongst sea­weed. All around 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 their heads; 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 (also re­ferred to as the il­li­cium), and is mov­able in all di­rec­tions; this mod­i­fied fin ray is used as a lure to at­tract other fish, which the monk­fish then seize with their enor­mous jaws, de­vour­ing them whole. 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 fully swal­low prey as large as itself. Monk­fish grow to a length of more than 150 cm (4.9 ft); spec­i­mens of 100 cm (3.3 ft) are common.

Reproduction
The spawn of this genus con­sists of a thin sheet of trans­par­ent gelati­nous ma­te­r­ial 60–100 cm (2.0–3.3 ft) wide and 8–10 m (26–33 ft) 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 along 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 me­tres (2,600 ft) to deeper wa­ters (greater than 1,000 me­tres, 3,300 ft). 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). Also, minor dif­fer­ences in their dis­tri­b­u­tion occur. 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 the Bar­ents Sea to the Strait of Gibral­tar). De­spite these dif­fer­ences, the over­all dis­tri­b­u­tion of the black and white an­gler­fish tend to over­lap greatly. 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 a mix­ing of both north­ern and south­ern species 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 usu­ally caught by trawl and gill­net­ting fleets.

Con­cern is ex­pressed 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.