The greatest depth reached hitherto by a dredge in which fishes were enclosed is 2900 fathoms. But the specimens thus obtained belong to a species (Gonostoma microdon), which seems to be extremely abundant in upper strata of the Atlantic and Pacific, and were therefore most likely caught by the dredge in its ascent. The next greatest depth, viz., 2750 fathoms, must be accepted as one at which fishes undoubtedly do live; the fish obtained from this depth of the Atlantic, Bathyophis ferox, showing by its whole habit that it is a form living on the bottom of the ocean.
The fish-fauna of the deep sea is composed chiefly of forms or modifications of forms which we find represented at the surface in the cold and temperate zones, or which appear as nocturnal pelagic forms. The Chondropterygians are few in number, not descending to a depth of more than 600 fathoms. The Acanthopterygians, which form the majority of the coast and surface faunas, are also scantily represented; genera identical with surface types are confined to the same inconsiderable depths as the Chondropterygians, whilst those Acanthopterygians which are so much specialised for the life in the deep sea as to deserve generic separation, range from 200 to 2400 fathoms. Three distinct families of Acanthopterygians belong to the deep-sea fauna, viz. Trachypteridæ, Lophotidæ, and Notacanthidæ; they respectively consist of three, one, or two genera only.
Gadidæ, Ophidiidæ, and Macruridæ are very numerous, ranging through all depths; they constitute about one-fourth of the whole deep-sea fauna.
Of Physostomi, the families of Sternoptychidæ, Scopelidæ, Stomiatidæ, Salmonidæ, Bathythrissidæ, Alepocephalidæ, Halosauridæ, and Murænidæ are represented. Of these the Scopeloids are the most numerous, constituting nearly another fourth of the fauna. Salmonidæ are scarce, with three small genera only. Bathythrissidæ include one species only, which is probably confined in its vertical as well as horizontal range; it occurs at a depth of about 350 fathoms in the sea of Japan. The Alepocephalidæ and Halosauridæ, known before the “Challenger” expedition from isolated examples only, prove to be true, widely-spread, deep-sea types. Eels are well represented, and seem to descend to the greatest depths.
Myxine has been obtained from a depth of 345 fathoms.
It will be useful to append a complete list of Deep-sea fishes, with the depths as ascertained by the dredgings of the “Challenger:”—
List of Deep-sea Fishes.
| Fathoms. | |
| Chondropterygians— | |
| Raja | 565 |
| Scyllium | 400 |
| Centroscyllium | 245 |
| Centrophorus | 345–500 |
| Acanthopterygians— | |
| Pomatomus | (? down to) 200 |
| Sebastes | 275 |
| Setarches | 215 |
| Beryx | 345 |
| Melamphaes | (? beyond) 200 |
| Polymixia | 345 |
| Nealotus | |
| Nesiarchus | |
| Aphanopus | |
| Euoxymetopon | |
| Lepidopus | 345 |
| Gempylus | |
| Anomalops | |
| ? Antigonia | |
| Diretmus | |
| Cottus | 565 |
| Bathydraco | 1260 |
| Oneirodes | |
| Melanocetus johnsonii | 1850 |
| „ bispinosus | 360 |
| Himantolophus | |
| Chaunax | 215 |
| Ceratias | 2400 |
| Halieutichthys | |
| Dibranchus | 360 |
| Trachypteridæ | |
| Lophotes | |
| Notacanthus rissoanus | 1875 |
| „ bonapartii | 400 |
| Anacanthini— | |
| Melanonus | 1975 |
| Lotella marginata | 120–345 |
| Physiculus | 345 |
| Uraleptus | |
| Læmonema | |
| Haloporphyrus australis | 55–70 |
| „ lepidion | 345–600 |
| „ rostratus | 600–1375 |
| Chiasmodus niger | 1500 |
| Sirembo grandis | 1875 |
| „ macrops | 375 |
| „ messieri | 345 |
| „ ocellatus | 350 |
| „ brachysoma | 350 |
| Acanthonus armatus | 1075 |
| Typhlonus nasus | 2440 |
| Aphyonus gelatinosus | 1400 |
| Rhinonus ater | 2150 |
| Bathynectes laticeps | 2500 |
| „ compressus | 1075–2500 |
| „ gracilis | 1400 |
| Pteridium | |
| Macrurus (12 species) | 120–700 |
| Coryphænoides norvegicus | |
| „ serratus | |
| „ nasutus | 345–565 |
| „ villosus | 345 |
| „ rudis | 500–650 |
| „ æqualis | 600 |
| „ crassiceps | 520–650 |
| „ microlepis | 215 |
| „ murrayi | 1100 |
| „ serrulatus | 700 |
| „ filicauda | 1800–2650 |
| „ variabilis | 1375–2425 |
| „ affinis | 1900 |
| „ carinatus | 500 |
| „ longifilis | 565 |
| „ altipinnis | 565–1875 |
| „ asper | 500–1875 |
| „ leptolepis | 350–2050 |
| „ sclerorhynchus | 1090 |
| „ denticulatus | 275–520 |
| Malacocephalus | 350 |
| Bathygadus cottoides | 520–700 |
| „ multifilis | 500 |
| Sternoptychidæ— | |
| Argyropelecus | 1127 [?] |
| Sternoptyx | 0–2500 [?] |
| Polyipnus | 255 |
| Gonostoma denudatum | |
| „ microdon | 500–2900 [?] |
| „ elongatum | 360–800 |
| „ gracile | 345–2425 |
| Chauliodus | 565–2560 |
| Scopelidæ— | |
| Bathysaurus ferox | 1100 |
| „ mollis | 1875–2385 |
| Bathypterois longifilis | 520–630 |
| „ longipes | 2650 |
| „ quadrifilis | 500–770 |
| „ longicauda | 2550 |
| Chlorophthalmus agassizii | 215 |
| „ nigripinnis | 120 |
| „ gracilis | 1100–1425 |
| Scopelus engraulis | 255 |
| „ antarcticus | 1950 |
| „ antarcticus | |
| „ mizolepis | 800 |
| „ dumerilii | 215 |
| „ macrolepidotus | 520–630 |
| „ crassiceps | 675–1550 |
| „ macrostoma | 2350–2425 |
| „ microps | 1375 |
| Odontostomus hyalinus | |
| Odontostomus humeralis | 500 |
| Nannobrachium nigrum | 500 |
| Ipnops murrayi | 1600–2150 |
| Paralepis | |
| Sudis | |
| Plagyodus | |
| Stomiatidæ— | |
| Astronesthes niger | 2500 [?] |
| Stomias boa | 450–1800 |
| „ barbatus | |
| „ ferox | |
| Echiostoma barbatum | |
| „ micripnus | 2150 |
| „ microdon | 2440 |
| Malacosteus niger | |
| „ indicus | 500 |
| Bathyophis ferox | 2750 |
| Salmonidæ— | |
| Argentina | |
| Microstoma | |
| Bathylagus antarcticus | 1950 |
| „ atlanticus | 2040 |
| Bathythrissidæ— | |
| Bathythrissa dorsalis | 345 |
| Alepocephalidæ— | |
| Alepocephalus rostratus | |
| „ niger | 1400 |
| Platytroctes apus | 1500 |
| Bathytroctes microlepis | 1090 |
| „ rostratus | 675 |
| „ macrolepis | 2150 |
| Xenodermichthys | 345 |
| Halosauridæ— | |
| Halosaurus owenii | |
| „ affinis | 565 |
| „ macrochir | 1090–1375 |
| „ mediorostris | 700 |
| „ rostratus | 2750 |
| Murænidæ— | |
| Nemichthys scolopacea | |
| „ infans | 500–2500 |
| Cyema atrum | 1500–1800 |
| Saccopharynx | |
| Synaphobranchus pinatus | 345–1200 |
| „ bathybius | 1875–2050 |
| „ brevidorsalis | 1075–1375 |
| „ affinis | 345 |
| Nettastoma parviceps | 345 |
| Cyclostomata— | |
| Myxine australis | 345 |
Fig. 111.—Chiasmodus niger; obtained in the North Atlantic at a depth of 1500 fathoms; the specimen has swallowed a large Scopelus (s); o, ventral fin.