Salmonide

salmon species rivers fish trout lakes eggs loch water time

SALMONIDE - gallivensis, Gunther. An anadromous species from Galway, distinguished by the acutely pointed but not elongate snout, broad convex head, small eye, feeble teeth, feeble maxillary and mandible, and by extremely thin and short pyloric appendages, which are not longer than one inch nor thicker than a pigeon's quill. According to Day a variety of S. fario.

S. fcrox, Jard. and Selby (Edinb. New Philos. Journal, 1835, xviii.). A non-migratory species inhabiting the large lochs of the north of Scotland and several lakes of the north of England, Wales, and Ireland. Pmoperculuna crescent-shaped, the hinder and lower margins passing into each other without forming an angle. According to Day a variety of S. Janie.

S. orcadensis, Giinther, from Loch Stennis in Orkney.

S. stomachicus, Gunther (the Gillaroo). From lakes of Ireland. Thick stomach. Feeds on shells (Limnmus, Ancylus).

S. nigripinnis, Gunther. Non-migratory species inhabiting mountain pools of Wales, also Lough Melvin, Ireland.

Day mentions also the following varieties of S. fario : - S. cornubiensis, Walb., Artedi ; Swaledale trout, from Swaledale, Yorkshire ; and Crassapuill trout, from Loch Crassapuill, SutheHandshire.

Many species of Salmo exist which are confined to limited areas in the continent of Europe. An account of these is given in the Brit. Mus. Catalogue, which also contains references to the literature. Oue of these, S. nwtcrostigma, Dumeril, is a non-migratory form occurring in Algeria, and is the southernmost species of the Old World. Three non-migratory species exist in the rivers belonging to the basin of the Adriatic. In the Alpine lakes of central Europe five species are known, which resemble in habits the forms found in British lakes, ascending the streams which feed the lakes, in order to spawn. Two of these species inhabit the Lake of Constance, one the Lake of Geneva. Earl° argenteus, env. and Val., found in the Atlantic rivers of France, is considered by Dr Gunther a distinct species, by Mr Day as a synonym of S. trutta. One migratory species is known from the Eidfjord river in Norway ; two land-locked species from Lake Wener in Sweden.

The species of Salmo belonging to the Pacific Coast of North America have been described by Richards in Faun. Bor. Amer., by Suelley in Nat. Hist. Washington Territory, and by Girard in Proc. Acad. Nat. Sc. Philacl. Only one species need be mentioned here, and that on account of the importance it has acquired in connexion with the work of the United States Fish Commission : - Salmo irideus, Gibbons (Proc. Cal. Ac. Nat. Sc., 1855, p. 36); Salar iridca, Girard (Proc. Acad. Nat. Sc. Philad., 1856, p. 220 and U. S. Pac. B. B. Explor. - Fish, p. 321, pl. 73,1.5, and pl. 74) (the Californian, Mountain, or Rainbow Trout). B. 10 ; D. 14 ; A. 14 ; L. lat. 140. Caudal deeply marginate. Body and dorsal and caudal fins with numerous small black spots. A non-migratory species in rivers of Upper California.

For the same reason as in the preceding case, the following-species of the eastern slope of the North American continent is introduced :- Salmo namayeash, Penn (Arct. Zool., ii. p. 139), Cuv. and Val. (xxi. p. 348) (Lake Trout). B. 11-12 ; D. 13-14 ; A. 12 ; V. 9 ; L. lat. 220. PrteopercnIum very short, without lower limb ; head very large. Teeth strong ; those on the vorner persistent throughout life, and in single series. Inhabits all the great lakes of the northern part of North America.

B. Subgenus SALVELINITS : - Salmo alpinus, L. (the Charr, Yarnell, Brit. Fishes, 3d ed.).

D. 13 ; A. 12 ; P. 13 ; V. 10 ; L. lat. 195-200 ; Vert. 59-62 ; Crec. pyl. 36-42. Body slightly compressed and elongate. Length of head equal to height of body in mature specimens and two-ninths or one-fifth of total length ; maxillary extends but little beyond the orbit in the fully adult fish. Eye one-half, or less than one-half, of the width of the interorbital space. Teeth of moderate size. Inhabits lakes of Scandinavia, Scotland (Helier Lake, Hoy Island, Orkneys ; Sutherlandshire ; Loch Roy, Inverness-shire), and probably Iceland.

S. killinensis, Giinther (Proc. Zool. Soc., 1865, p. 699). D. 1415 ; A. 13 ; P. 13 ; V. 9 ; L. lat. 180 ; Vert. 62 ; Ctec. pyl. 4452. Head, upper parts, and fins brownish black ; lower parts with an orange-coloured tinge in the male ; sides with very small, light, inconspicuous spots. Anterior margins of the lower fins white or light-orange-coloured. Loch Killin, Inverness-shire. Considered by Mr Day as a variety of S. alpinus.

S. willughbii, Gunther (Proc. Zool. Soc., 1862, p. 46, pl. 5) ; Charr, Willughby (Hist. Pisc., p. 196), Penn (Brit. Zool. ), and Yarrell (Brit. Fish., 3d ed.) (the Charr of Windermere). D. 1213 ; A. 12 ; P. 13-14 ; V. 9-10 ; L. lat. 165 ; Vert. 59-62 ; Ceec. pyl. 32-44. Sides with red dots ; belly red ; pectoral, ventral, and anal with white margins. Lake of Windermere ; Loch Bruiach (Scotland). Considered by Mr Day as a variety of S. alpinus.

S. perisii, Giinther (Ann. and Mag. Nat. Hist., 1865, p. 75); Torgoch, Willughby (Hist. Pisc.) and Penn (Brit. Zool.) (the Torgoch or Red Charr). D. 13 ; A. 12 ; P. 12 ; V. 9 ; L. lat. 170 ; Vert. 61 ; Care. pyl. 36. Sides with numerous red dots ; belly red in the mature fish ; pectoral, ventral, and anal with white margins. Lakes of North Wales (Llanbcrris). Considered by Mr Day as a variety of S. alpinus.

S. grayi, Giinther (Proc. Zool. Soc., 1862, p. 51). D. 13 ; A. 12 ; P. 13-14 ; V. 9 ; L. lat. 125 ; Vert. 60 ; Ca c. pyl. 37. Sides with scattered light-orange-coloured dots ; belly uniform silvery whitish, or with a light-red shade ; fins blackish. Lough Melvin, Ireland. Considered by Mr Day as a variety of S. alpinus.

S. colii, Gfinther (Proc. Zool. Soc., 1863) (Cole's Charr, Couch, Fish. Brit. Isles). D. 14 ; A. 12 ; P. 13 ; V. 9 ; L. lat. 160 ; Vert. 63 ; Czec. pyl. 42. Bluish black above ; sides silvery with scattered light-salmon-coloured dots ; belly reddish ; fins black, the anal and the paired fins with a reddish tinge, the anal and ventrals with a narrow whitish margin. A small species 7 to 8 inches long from Loughs Eske and Dan, Ireland. Considered by Mr Day as a variety of S. alpinus.

The above are all the British species.

S. umbla, L. (Syst. Nat.), Cuv. and Val. D. 12 ; A. 12-13 ; P. 14 ; Y. 9 ; L. lat. 200 ; Vert. 65 ; Case. pyl. 36. Commonly called in French Ombre Chevalier. Lower parts whitish or but slightly tinged with red. Lakes of Constance, Neuchatel, and Geneva. Considered by Mr Day as identical with S. alpinus. Other species have been described from lakes in Europe and Asia, but are imperfectly known ; for an account of them see Giinther's Catalogue.

The following American species of Charr is one of those cultivated by the American Fish Commission :- S. (Salvelinus) fontinalis, Mitch. (Trans. Lit. and Phil. Soc., New York, i. p. 435), Cuv. and Val. (xxi. p. 266) (Brook Trout). B. 12; D. 12; A. 10; L. lat. 200; Case. pyl. 34. No median series of teeth along the hyoid bone. Preeoperculum short in longitudinal direction, with the lower limb very indistinct. Rivers and lakes of British North America, and of the northern parts of the United States. Introduced in Britain.

Of the genus Osmerus only three species are described in the Brit. lltus. Cat., one of which is British : - Osmerus cperlanus, Lacep., Linn. (the Smelt ; Fr., Eperlan ; Scotch, Sparling or Spirling). B. 8 ; D. 11 ; A. 13-16 ; P. 11 ; V. 8 ; L. lat. 60-62 ; L. transverseirr ; Czec. pyl. 2-6 ; Vert. 60-62. Height of body much less than length of the head, which is a quarter or two-ninths of the total length to base of caudal fin. Snout produced. Vornerine teeth and anterior lingual teeth large, fang-like ; posterior mandibular teeth larger than the anterior ones, which form a double series, the inner series containing stronger teeth than the outer one. Back transparent, greenish ; sides silvery. Adult size 10 or 12 inches. Coasts and numerous fresh waters of northern and central Europe.

Osmerus viridescens, Lesueur, another species scarcely distinct from 0. eperlanus, but with scales a little smaller, occurring on the Atlantic side of the United States.

Osmerus thaleichthys, Ayres, occurs abundantly in the Bay of San Francisco.

Of Coregonus forty-one species are described in the Brit. Illus. Cat. Four species are found in Britain :- C. oxyrhynchus, Kroyer, Linn., Cuv. and Val. (xxi.). Called the Routing in Holland. B. 9 ; D. 14 ; A. 14-15 ; L. lat. 75-81 ; L transverse 9.1.12° ; Vert. 58. Snout produced, with the upper jaw protruding beyond the lower, and in adult specimens produced into a fleshy cone. Length of the lower limb of operculum 1 to lf times that of the upper. Pectoral as long as the head without snout. Found on coasts and in estuaries of Holland, Germany, Denmark, and Sweden. Captured recently (three specimens only) in Lincolnshire, near Chichester, and at the mouth of the Medway.

C. clupeoides, Lacepede ; C. pennantii, Cuv. and Val. (the Gwyniad of Lake Bala, Schelly of Ullswater, Powan of Loch Lomond; sometimes called the Freshwater Herring). B. 9 ; D. 14-15; A. 13- 16 ; L. lat. 73-90; L. transverse 1-9- ; Czec. pyl. 120; Vert. 38/20. Snout with upper jaw not produced. Pectoral larger than the head. Fins black or nearly so. Lakes of Great Britain.

C. vandesius, Richards (Faun. Bor. Amer.); C. albula, Cuv. and Val. (the Veudace). D. 11 ; A. 13 ; V. 11 ; L. lat. 68-71 • L. transverse /97r; Vert. 56. Castle Loch, Lochmaben in Dumfriesshire.

C. pollan, Thompson (Proc. Zool. Soc., 1835), Cuv. and Val. (the Pollan). D. 13-14 ; A. 12-13 ; V. lt ; L. lat. 80-86; L. transverse 19r ; Vert. 60-61. Two jaws of same length. Teeth if present very minute. Bluish along the back, silvery along the sides and beneath. Usual length of adults 10 to 11 inches, maximum 13 inches. Ireland, in Loughs Neagh, Erne, Derg, Comb, and the Shannon.

Thirty-seven species of Coregonus have been distinguished besides these four. Some are migratory ; but the greater number are inhabitants of large lakes. The anadromous species are confined to the Arctic Sea, and the greater number belong to the coast and rivers of Siberia. Several distinct species occur in the lakes of Sweden ; a few are found in the lakes of Switzerland and central Europe. C. hicmulis is peculiar to the Lake of Constance. Several species inhabit the great freshwater lakes connected with the river St Lawrence of North America, and the lakes farther to the north. One of these is cultivated by the American Fish Commission : - Coregenus dupe(formis, Mitchell, Dekay (New York Fauna, Fish), Cuv. and Val., Agassiz (Lake Superior) (the Shad Salmon, Freshwater Herring, Whitefish). D. 12 ; A. 14 ; L. lat. 76-77 ; L. transverse A. The snout ispointed, and there is an appendage te the ventral fin which is half as long as the fin itself. Length of adult 11 to 13 inches. Lakes Erie and Ontario.

Only one species of Thymallus occurs in the British Islands : - Thyniallus rulgaris, Nilsson ; Thymallus ucxillifer, Cuv. and Val. (the Grayling ; French, L'Onibre ; Italian, Temelo). B. 7-8 ; D. 20-23 ; A. 13-16 ; P. 16 ; V. 10-11 ; L. lat. 75-85 ; L. transverse 14-1 ; Ctee. pyl. 22; Vert. 39/22. Length of head two-ninths or one-fifth of total length to base of caudal ; posterior dorsal rays somewhat produced in adult. Grows to 15 inches in length. A freshwater fish, common in many of the rivers of England, introduced into some of those of southern Scotland ; absent from Ireland. It is widely distributed in central and northern Europe, occurring in Lapland, Sweden, Lake of Constance, the Isar, and the Danube. Adult size about 15 inches.

Thymallus mliani, Cuv. and Val. (04toaos, eEl., xiv. 22), occurs in Lago Maggiore. One species has been described from Siberia, and two are known inhabiting Lake Michigan and the waters of British North America.

Of Argentina four species are described in the Brit. Mus. Cat., namely : - Argentina silus, Nilsson, occurring off the north-west coast of Norway, Argentina sphymna, L., from the Mediterranean, Argentina hebridica, Nilsson, found on the coasts of Norway and Scotland, and Argentina lioglossa, Cuv. and Val. According to Mr Day, two of these, A. sphyrrena and A. hebridica are identical, the species ranging from the coast of Norway and east and west shores of Scotland to the Mediterranean. The following is the formula of A. hebridica, Nilsson, according to Giinther : - D. 9-11 ; A. 13 (12) ; P. 13-14 ; V. 11 ; L. lat. 52-53 ; Cree. pyl. 14-20 ; Vert. 52. The scales with minute spines.

The species of Oncorhynehns are all anadromous, and are confined to American and Asiatic rivers flowing into the Pacific. 0. quinnat, Richardson a 0. choiticluz occurs in the river Sacramento, and is cultivated by the American Fish Commission.

Plecoglossus comprises small aberrant freshwater species abundant in Japan and the island of Formosa.

Retropinna contains but one species, R. riehardsonii, which is known as the New Zealand Smelt. It is common on the coasts of New Zealand, ascending estuaries. Like Osmerus eperlanus, it is landlocked in fresh water in some localities.

Of Mallotus only one species is described by Gunther: - Ma/lotus rillosus, Cuv. and Val., Mull. (the Capelin ; French, Capelan). B. 8-10 ; D. 13-14 ; A. 21-23 ; P. 18-20 ; V. 8 ; Ctec. pyl. 6 ; Vert. 68. Brownish on the back, silvery on the sides. Operculum silvery with minute brown dots. Shores of Arctic North America and of Kamchatka.

Of the genus Salanx two species are known: - Salanx chinensis, Gunther, Osbeck, which is common on the coast of China and called " Whitebait" at Macao, and Salanx microdon, Bleeker, from the rivers of Jcddo.

Microstoma. - M. rotundatum, Risso, is marine and occurs in the Mediterranean ; it is not anadromous. It is the only species of the genus known, unless the Microstomits grtinlanclicus, described by Reinhardt, from the Sea of Greenland, really belongs to this genus.

For Bathylagus, see p. 222 above.

Up to a period not many years past, when our knowledge of the breeding and life history of the salmon and kindred species was based entirely on desultory observations of the fish in their natural conditions, there existed a great deal of uncertainty and diversity of opinion on the subject. Within the last twenty or thirty years the extensive practice of salmon-culture has removed nearly all obscurity from the phenomena, and the history of Salmonoids is now more accurately known than that of most other fishes.

The salmon proper, Salmo salar, breeds in the shallow running waters of the upper streams of the rivers it ascends. The female, when about to deposit her eggs, scoops out a trough in the gravel of the bed of the stream. This she effects by lying on her side and ploughing into the gravel by energetic motions of her body. She then deposits her eggs in the trough ; while she is engaged in these operations she is attended by a male, who sheds milt over the eggs as the female extrudes them, fertilization being, as in the great majority of Teleostel, external. The parent fish then fill up the trough and heap up the gravel over the eggs until these are covered to a depth of some feet. The gravel heap thus formed is called a "redd." The period of the year at which spawning takes place in the British Isles, and in similar latitudes of the northern hemisphere, varies to a certain extent with the locality, and in a given locality may vary in different years ; but, with rare exceptions, spawning is confined to the period between the beginning of September and the middle of January.

The eggs of Salmo salar are spherical and non-adhesive ; they are heavier than water, and are moderately tough and elastic. The size varies slightly with the age of the parent fish, those from full-sized females beinig slightly larger than those from very young fish. According to rough calculations made at salmon-breeding establish ments, there arc 25,000 eggs to a gallon ; the diameter is about a quarter of an inch. It is usually estimated that a female salmon produces about 900 eggs for each pound of her own weight ; but this average is often exceeded.

The time between fertilization and hatching, or the escape of the young fish from the egg-membrane, varies considerably with the temperature to which the eggs are exposed. It has been found that at a constant temperature of 41° F. the period is 97 days ; but the period may be as short as 70 days and as long as 150 days without injury to the health of the embryo. It follows therefore that in the natural conditions eggs deposited in the autumn are hatched in the early spring. The newly hatched fish, or " alcvin," is provided, with a very large yolk-sac, and by the absorption of the yolk contained in this the young creature is nourished for some time ; although its mouth is fully formed and open, it takes no food. The alevin stage lasts for about six weeks, and at the end of it the young fish is about inches long. During the next period of its life the young salmon is called a "parr," and is distinguished by the possession of a number of dark transverse marks along the sides, known as "parr marks." These marks occur in the young stage of many species among the Salmonidx. The parr doubles its length in about four months.

The great majority of parr remain in fresh water for two years after hatching, at the end of which time they are about 8 inches in length. The second spring after they are hatched they develop a coating of bright silvery scales which completely conceals the parr marks, and they pass into a stage in which they are known as "smelts." The smolt is similar to the adult salmon in all respects except size, and the young salmon, as soon as the smolt stage is reached, migrates down the rivers to the sea.

The above facts have been established within recent years by accurate observation and experiment. Not very long ago it was a disputed question whether the parr was the young salmon or a distinct species of fish. That the former view was correct was first experimentally proved by Mr John Shaw, gamekeeper to the duke of Buceleuch, Drumlanrig, Dumfriesshire, who in 1833 isolated several parrs in a pond, and found that in April 1834 they changed into smolts ; an account of this experiment was published in the Transactions of the Royal Society of Edinburgh. The question is now of merely historical interest, for at the present time large numbers of parr are hatched at various fish-hatching establishments every season. By observation at these establishments, the knowledge of the history of the parr and the migration of the smolt which had been gained by the study of the fish in their natural conditions has been rendered more accurate and complete.' It has been conclusively ascertained that some parr become smelts and migrate to the sea in the spring following that in which they were hatched, while the great majority remain in the parr stage until the second spring, and a few do not attain to the smolt condition until the third year. The male parr when only 7 or 8 inches in length is often sexually mature, the milt being capable of fertilizing the ova of an adult female salmon.

The migration of smelts to the sea takes place in all rivers at about the same time of the year, viz., between March and June. Sometimes the smelts are observed descending in large shoals. Formerly angling for the descending smelts was a recognized sport, but their capture is now illegal. It is the opinion of the most competent authorities that the smelts increase with wonderful rapidity in size and weight when they reach the sea, and then return to the rivers after a few months, during the same year, as "grilse," which name is given to sexually mature salmon up to a little over 5 lb in weight. It is surprising that a smolt weighing only a few ounces should increase to 3 or 4 or even 6 lb in about three months. Nevertheless it has been proved by actual experiment that this is the fact. At Stormontfield, in May 1855, 1300 smelts were marked by cutting off the adipose fin, and 22 of these were recaptured the same summer as grilse, weighing from 3 lb upwards. It might be supposed that some smelts do not return as grilse till the summer following the year of their descent, the time of their stay in the sea being variable, as is the period spent by parr in the rivers. But all the evidence is against this supposition; grilse never commence ascending till late in summer ; if they had been more than a year in the sea, some would probably ascend early in the season, as do the larger salmon. At the same time it must be borne in mind that a fish which remained in the sea a year after descending as a smolt might not be recognized as a grilse, having reached the size of a small salmon.

The grilse, after spawning in autumn, return again to the sea in the winter or following spring, and reascend the rivers as mature spawning salmon in the following year. Both salmon and grilse after spawning are called " kelts." The following recorded experiment illustrates the growth of grilse into salmon : - a grilse-kelt of 2 lb was marked on March 31, 1858, and recaptured on August 2 of the same year as a salmon of 8 lb.

The ascent of rivers by adult salmon is not so regular as that of grilse, and the knowledge of the subject is not at the present time complete. Although salmon scarcely ever spawn before the month of September, they do not ascend in shoals just before that season ; the time of ascent extends throughout the spring and summer. A salmon newly arrived in fresh water from the sea is called a clean salmon, on account of its bright, well-fed appearance ; during their stay in the rivers the fish lose the brilliancy of their scales and deteriorate in condition. The time of year at which clean salmon ascend from the sea varies greatly in different rivers ; and rivers are, in relation to this subject, usually denominated early or late. The Scottish rivers flowing into the German Ocean and Pentland Firth are almost all early, while those of the Atlantic slope are late. The Thurso in Caithness and the Naver in Siitherlandshire contain fresh-run salmon in December and January ; the same is the case with the Tay. In Yorkshire salmon commence their ascent in July, August, or September if the season is wet, but if it is dry their migration is delayed till the autumn rains set in. In all rivers more salmon ascend immediately after a spate or flood than when the river is low, and more with the flood tide than during the ebb.

In their ascent salmon are able to pass obstructions, such as waterfalls and weirs of considerable height, and the leaps they make in surmounting such impediments and the persistence of their efforts are very remarkable. In a great many rivers anadromous Salmonoids have been excluded from the upper reaches by artificial obstructions, such as dams and weirs, constructed for the purpose of utilizing the water of the stream, or to obtain water power, or simply to facilitate the capture of the fish. Other rivers have been rendered uninhabitable to salmon by pollutions. The state of the Thames within the boundaries of London has since the beginning of the present century excluded Salmonoids entirely from the river ; but every season salmon and grilse are taken in or near the Thames estuary, and there is no doubt that if the water could again be rendered moderately clear, and if fish-ways were provided at the impassable weirs, the upper waters of the Thames would again be frequented by salmon and migratory trout.

The life history of Salnio trutta and S. cambricus is very similar to that of Salm° solar. The river trout, S. fario, makes a redd in the shallower parts of streams in the same manner as the salmon, the only difference being that the mound of gravel forming the redd is smaller, the egg lying from one to two feet below the surface. The breeding period of the trout varies in different rivers, within the limits of September and March.1 The number of eggs produced by each female is about 800 for every pound of the parent's weight ; about 40,000 of the eggs make a gallon, so that they are considerably smaller than those of S. solar. The trout of Loch Leven, S. levenensis, ascend the streams feeding the loch, in order to spawn, at the end of September and beginning of October. The habits of other species of lake trout are similar to those of S. levenensis.

The charrs differ from lake trout in the fact that they do not ascend streams in order to spawn, but form their redds in the gravelly shallows of the lakes they inhabit. The spawning ri peod of the charr of the Cumberland lake district is from the beginning of November to the beginning of December. The eggs of the charr have been found to hatch in from 60 to 90 days, the great majority in 70 days, at an average temperature of 40° F. The American species, S. fontinalis, breeds at about the same time as S. fario ; its eggs are only half the size of those of the latter.

The smelt, 0. eperlanus, is a gregarious fish and exhibits regular migrations in most estuaries. It is common in the Solway, the Firth of Forth, the rivers of Norfolk, and the estuary of the Thames. In most places where it is found it remains in the fresh and brackish water from August until May, spawning about the month of April, and afterwards descending to the sea for the summer. At Alloa on the Forth smelts are taken in large numbers by seine nets in spring, before and during the spawning period. There is a regular fishery for them at the same season on the Solway Firth and in Norfolk. The food of the smelt consists chiefly of young fish, especially young herrings, and crustaceans. The eggs are small, yellowish in colour, and adhesive, not adhering by the surface merely as is the case with those of the herring, but each egg possessing a short thread the end of which becomes attached to planks, stones, or other solid objects in the water. According to Mr Day the eggs are deposited near the high-water mark of spring-tides, so that they must be exposed to the air during the ebb. The smelt when in the sea is largely eaten by the picked dog-fish (Acanthias vulgaris). The species is absent from the southern coast of England and from Ireland, the smelt recorded as occurring on those coasts being probably the atherine (Atherina), often called the sand-smelt. O. eperlanus is abundant on the coast of Finland, and also is common there in freshwater lakes, in which it remains all the year round. It is also common on the Atlantic coast of France. It is of interest to note that the smelt in Britain and on other coasts, when not confined to fresh water, is, in its migration, intermediate between anadromous Salmonidx, which ascend to near the sources of rivers, and such fish as the herring, which approach the shore to spawn but do not usually enter rivers. The smelt as a rule ascends estuaries only as far as the region of brackish water.

The various species of Coregonus resemble the charr in their habits, spawning in the autumn in the shallows of the lakes they inhabit ; their ova are small, and, as mentioned in PISCICULTURE (q.v.), are non-adhesive and of almost the same specific gravity as fresh water, so that they are semi-buoyant.

The grayling, Thymallus vulgaris, is in Britain exclusively fluviatile ; in Scandinavia it is found also in lakes. It is met with chiefly in clear streams with sandy gravels or loamy beds. It was introduced not many years ago into the Tweed by the marquis of Lothian, and thrives there. It is absent from the . Thames, but is common in most of the rivers of England and Wales - e.g., the rivers of Yorkshire, the Severn, and the Wye. It is absent from Ireland. It feeds on insects and their larva, crustaceans, and small molluscs. It breeds in April and May, depositing its ova on the surface of the gravel in the shallows, not in a redd. The ova are smaller than those of the trout, and vary in colour from white to deep orange, and they hatch from the twelfth to the fourteenth day after extrusion. The fry grow to 4 or 5 inches in length by August, and by the following autumn to 9 or 10 inches.

In England and Wales the common law is that every person has an equal right to fish for salmon in the sea and in navigable tidal rivers, while the proprietors of the soil on the banks of rivers which are not navigable have the exclusive right of fishing in them. The erection of stake-nets, or other fixed engines for the capture of salmon in estuaries or on the sea-coast is necessarily incompatible with the maintenance of the public right of fishing, and has therefore from very early times been regarded as illegitimate. There has consequently been a constant conflict between legislation and private interest over this point. By Magna Charta all fishing weirs were abolished except on the sea-coast, but the object of this seems to have been rather the protection of the freedom of navigation than the advantage of the salmon fisheries or the maintenance of a public right. In later times fixed engines were repeatedly declared illegal and their erection prohibited by statute. Finally in 1861 they were definitively abolished in all cases except where legal right to maintain them could be conclusively proved. The Salmon Fishery Act of 1861, of which the prohibition just referred to was one of the clauses, was based upon the report of a royal commission appointed in 1860 to inquire into the condition of the salmon fisheries, and it forms the basis of the regulations at present in force, all previous legislation being by it expressly abolished and superseded. It prohibited the capture of unclean and unseasonable salmon, made a uniform close season for England and Wales, ordained a weekly close season of forty-two hours, provided for the erection of fish-passes and regulated the use of fishing weirs on non-navigable rivers, vested the central authority of the salmon fisheries in the Home Office, and provided for the appointment of inspectors. In 1863 an Act was passed prohibiting the exportation of salmon during the close time. In 1865, as it was found, useless to legislate without machinery to enforce the law, an Act was passed to constitute fishery districts under the control of local boards of conservators appointed by the magistrates in quarter-sessions. These boards were empowered to enforce a licence duty on fishing implements used in public waters. One or two minor salmon fishery Acts were passed in succeeding years, but the next important piece of legislation on the subject was the Act of 1873, the two most important provisions of which are (1) that fishermen in public waters for every £50 of licence duty which they pay elect a member of the local board of conservators, and (2) that each board of conservators may make bye-laws for the regulation and improvement of the fisheries within its own district The annual close time for salmon in England and Wales at present for nets commences Aug. 14-Sept. 30 and closes Feb. 2-April 1, varying in different districts within the limits given ; for rods the close time is Sept. 30-Nov. 29 to Feb. 1-May 1. The law as regards close time for fixed engines was amended in 1879. The method of fishing followed iu the English and Welsh estuaries is in consequence of the above course of legislation that of sweep-nets worked from shore by boats ; a licence duty has to be paid for each net, and stake-nets along the coast are very rare. An inspector of salmon fisheries appointed by the Home Office reports annually.

In Scotland the salmon fishery customs in one respect differ much from those of England stake nets are the common and universal means of salmon capture in estuaries, although sweep nets are also employed. The reason of this is that originally all the salmon fishings belong to the crown or the grantees of the crown. The principal Acts regulating Scottish salmon fisheries are those of 1862 and 1868, but, as the previous statutes have never been repealed, the law on the subject is somewhat confused. Scotland has been divided into fishery districts managed by district boards. An annual close time of 168 days is enforced, lasting for nets from August 26 to September 14 until February 5 to February 25, and for rods from September 14 to November 20 until January 11 to February 25. The weekly close time lasts thirty-six hours, from Saturday night till Monday morning. The construction of cruives, mill-lades, dams, and water wheels and the size of the meshes of nets are all regulated. In 1882 the management of the salmon fisheries was placed together with that of the sea fisheries under the control of the reconstituted Scottish Fishery Board, to which power was given to appoint an inspector of salmon fisheries; by this official an annual report of the condition of the fisheries is presented through the Fishery Board to the Home Office.

The principal Act relating to Irish fisheries is that of 1863. Special Fishery Commissioners are responsible for tho carrying out of the legal regulations. The country is divided like England and Scotland into fishery districts under the jurisdiction of boards of conservators, by whom clerks and water bailiffs are appointed. A. scale of licensing duties is enforced, and all new fixed engines - that is, any beyond those which legally existed in 1862 - are illegal. The weekly close time in Ireland is of forty-eight hours' duration, from 6 A.M. Saturday to 6 A.M. Monday. The annual close time is for nets from July 16 to September 30 until January 1 to June 1, and for rods from September 14 to November 1 until January 1 to June 1. In Ireland as in England and Scotland an inspectorship of salmon fisheries exists, and the holder of the office makes an annual report to the Home Office on the condition of the fisheries.

Introduction of Species to 11'ew Areas by Human Agency.

Within the past few years, since great activity has been exhibited. in pisciculture generally, and especially in the culture of Salmonidse, various experiments have been made in the transportation of eggs or young fry of valuable species from their native habitats to distant parts of the world. The American so-called brook trout, S. fontinalis, has been imported somewhat largely into Britain by various salmon fishery proprietors. It thrives well in various places in England, Scotland, and Wales where it has been set free, - for example, in Norfolk rivers, near Guildford in Surrey, and in the stock ponds at Howietoun.

In Nature, July 16, 1885, an account was given of the introduction of the fry of the American landlocked salmon (S. salar, var. sebago) to the upper waters of the Thames. Eggs of S. namaycush, S. sebago, S. fontinalis, and Coregonus albus have been successfully forwarded from the hatcheries of the American Fish Commission to the Deutsche Fischerei-Verein in Berlin, and to the Societ6 d'Acclimatation at Paris.

The common trout of Britain, S. facto, was introduced with complete success into Tasmania nearly twenty years ago by Frank Buckland, and is now abundant in the Tasmanian streams, although it is reported to be much less valued as food there than at home. From Tasmania the eggs were transported to the rivers in Otago, New Zealand, where they also thrive and breed (see Trans. of Otago Institute, 1878). In 1866 Mr Francis Day introduced the fry of the same species into the rivers of the table-land of the Nilgiris in the neighbourhood of Madras. The experiment on this occasion failed, but two years later the establishment of the species in the district in question was successfully accomplished by Mr M'Ivor, who imported the fry from Scotland.

Salmon Culture.

For the artificial culture of Salmonoids the reader is referred to the article PISCICULTURE. The following account of the salmon and trout hatcheries in Scotland is abridged from a paper read before the Scottish Fisheries Improvement Association in Edinburgh, 26th November 1884, by J. Barker Duncan, the honorary secretary to the Association.

The principal institntion of Its kind in Scotland at present is the Ilewietoun Fishery, belonging to Sir J. Gibson Maitland, who commenced It in 1873. Howietoun to about four miles from Stirling. The establishment contains thirty-two fish ponds and a large hatching-house; there are also four ponds at Craigend, and one of 9 acres at Goldenhove, where fish are reared to their adult condition. The hatching-boxes are of wood, and the eggs are kept during development on glass grilles. The water supply is abundant, about a million gallons of spring water flowing through the ponds every twenty-four hours. The eggs hatched in greatest numbers are those of the Loch Leven trout, but Saline salar and the common trout (Salmo facto) are also extensively reared. The American brook trout, S. font fnalis, is also cultivated. More than ten millions of ova are annually treated at this hatchery. In 1884 ninety thousand young fish were distributed to various parts of Great Britain and Ireland., and two consignments of trout and one of salmon ova were successfully sent to New Zealand.

The Solway Fishery, belonging to Mr Joseph J. Armistead, was established in 1881, to supersede the Trentdale Fishery near Keswick, Cumberland. It is situated near the Solway in K irkeudbi ightshlre. Various kinds of trout and chary, salmon and sea-trout, grayling, and other h eshwater fish arc bred. The hatching-house is fitted to hatch about a million ova. Small and large quantities of ova are supplied to applicants for purposes of stocking or for experiments in fish culture.

The Stormontfichl Ponds were established in 1853 by proprietors of Tay fisheries. They are situated about 5 miles above Perth on the Tay and occupy about 2 acres of ground. The Slormontfield experiments above referred to were carried out at these ponds under the direction of Mr Robert 13u1st. The establishment Is now almost superseded by the Dupplin Hatchery, but is still used to some extent. The hatching-boxes, 360 In number, are in the open air, and the eggs are placed on gravel at the bottom of the boxes ; a larger percentage of loss occurs with this system than when glass grilles are used. Two of the ponds at Stormontfield are stocked with parr from, the Dupplin Hatchery, about 20,000 being placed in them in 1884 ; the purr are fed with ground liver, and are liberated in the river and its tribMaries when two years old.

The Dupplin Hatchery was instituted in 1882 by the Tay district board at Newmill, Dupplin Castle, on the river Earn, a tributary of the Tay. The hatching-house is supplied with spring water, and contains about 300,000 ova. The gia,a grille system Is adopted here, and the fry are liberated in the Tay and its tributaries when about forty days old.

There is a hatchery for Loch Leven trout erected In 1883 by the Loch Leven Angling Association, situated about 800 yards from the loch, beside a small stream, In the season of 1884-85 about 220,000 eggs were laid down. The fry are turned into the feeders of the loch five or six weeks after hatching. Before the erection of this hatchery Loch Leven was several times stocked with fry from the Howletoun Fishery. The great effect of stocking on the produce of Loch Leven is shown by the following figures 1884 over 15,000 trout were taken in the loch during the season from April to September ; during the preceding ten years the lake had been supplied with some thousands of fry in five several seasons ; previous to 1874 uo attempt at stocking had been made, and In that year the total catch was about 5000, In May 1884 the Linlithgow Palace Loch Hatchery was opened by its proprietor, Mr A. G. Anderson, fish merchant, Edinburgh, who holds a lease of the loch for angling purposes from the crown. The hatchery is intended chiefly to stock the loth, and Is capable of containing about 600,000 ova. Experiments on the cultivation of Salmo solar, var. sebago, from America, are also to be made here.

A private hatchery belonging to the marquis of Alba, capable of hatching about 250,000 ova, is situated at Culzean in Ayrshire. Salmon ova are obtained from the rivers Doon, StInchar, and Minnock, and the fry turned again into those rivers when about six weeks old. Chair, S. fontinalis, and Loch Leven trout are also hatched to stock the hill lochs of the estate of Culzean. According to Mr Young the number of salmon in the Doon has been considerably Increased by the artificial stocking from this establishment.

Another private hatchery, with a capacity of 50,000, is maintained on the Loch-buy estate, Isle of Mull, for the purpose of stocking the rivers and lakes on the property.

The Aberdeen Hatchery was established in Aberdeen by the district boards of the rivers Dee and Don. From 15,000 to 20,000 fry are hatched here every year and are conveyed 10 to 40 miles up the rivers Dee and Don and then liberated.

Various proprietors in Scotland have at various times erected small hatching-houses on the rivers ed their estates for the purpose of stocking, but these have not been maintained. The above-mentioned are the only salmon-rearing establishments of any importance at present in operation in Scotland.

Salmon Disease.

During the last few years salmon in a great many rivers have been observed to be 'Suffering from an epidemic cutaneous disease from which large numbers have died. So far as is known this disease in its epidemic form is quite a new phenomenon ; there can be little doubt that it must have occurred as a sporadic affection in former tinter, but it seems on the other hand probable that such mortality among salmon as has taken place in some recent seasons must have attracted attention if it occurred, even when accurate observation was rare. The disease was first noticed in 1877 in the Esk and the Nith, flowing into the Solway Firth, and since then it has destroyed very largo numbers of salmon in almost every river in Britain. The disease consists in ulcerations of the skin, which begin at one or several spots on the head and body, and ultimately extend to the whole surface of the fish. The diseased parts of the skin are found when examined to be covered with a fungoid growth, with the mycelium of a fungus consisting of plaited hyphw which extend into and ramify through the tissue of the derma and epidermis, causing the cells to die, until the superficial tissues decay and slough off, and inflammation and bleeding are produced in the deeper and surrounding parts. It is certain that the injury to the skin and flesh of the salmon is caused by the fungus. If a section of the edge of an affected spot be made, and examined microscopically, the cells are seen to be perfectly normal and healthy beyond. the region to which the hyphn extend, and the growing points of the hyphae are seen to be penetrating between and distorting these uninjured cells. It is evident therefore that the morbid alteration of the tissues follows the attack of the hyphos and does not precede it. The external superficial part of the mycelium covering a diseased spot of the skin bears the fructification of the fungus. This consists of zoosporangia, which are the enlarged blind terminal parts of certain of the hyphce, that stand out perpendicular to the surface of the mycelium. Each zoosporangium contains a multitude of spherical spores. These spores are of the kind technically called zoospores, each on its escape from the sporangium moving about actively by means of two vibratile cilia. The zoosporangium emits the zoospores by an aperture at its end, and when it has emptied itself the hypha begins to grow again at the base of the empty membrane and sends up through the cavity of the old zoosporangium a new sprout which becomes a second spore capsule. This feature is characteristic of the genus Saprolegnia, belonging to the Oosporex, various kinds of which are well known to botanists ; they usually occur in dead insects or other invertebrate animals in water : the dead bodies of the common house-fly when in a sufficiently moist place almost invariably produce a luxuriant crop of Saprolegnice. The commonest species of Saprolegnia is S. ferax, and the salmon fungus has usually received the same name, as though it were a proved fact that it was identical with that species. But the species of a Saprolegnia can only be ascertained from the characters of its oosporangia, which are quite different from the zoosporangia and are produced much more rarely, and whose contents, the oospores, are fertilized by the contents of simultaneously produced antheridia. Mr Stirling has observed the oosporangia of salmon fungus (see his papers in Proc. Roy. Soc. Ed., 1878 and 1879), but his description is not sufficient to put the identification of the species beyond a doubt. From Prof. Huxley's experiments it is evident that the salmon fungus may reproduce for very many generations without the appearance of oospores. The salmon fungus grows with great luxuriance on other animal substances. In a diseased salmon the fungus seems to be confined to the skin and not to give rise to bacteria-like bodies in the internal organs. What are the conditions which favour the infection of salmon in a river is a question to which at present no answer can be given. Until it is known under what conditions the Saprolegnia exists in a river before infecting the salmon, the conditions which favour or prevent salmon disease cannot be ascertained. The fungus may have its permanent nidus in decaying vegetable substances, but at present it has not been determined whether it is possible to cultivate the salmon Saprolegnia on vegetable matter; or the disease may be propagated sporadically among the fish, Salmonoids and others, which are permanent residents of the rivers ; or its abundance may depend on the amount of dead animal matter that is available for its nutrition. There is probably always some Saprolegnia in every river ; the secondary conditions which determine whether or not the fungus shall multiply on the anadromons salmon to such an extent as to cause an epidemic have pet to be ascertained.

Literature. - Albert Giinther, Catalogue of Fishes in Brit. Ma., London. 1866, vol. vi. ; Id., Introduction to Study of Fishes, Edinburgh, 1880; Francis Day, Fishes of Great Britain and Ireland, London and Edinburgh, 1880 to 1884, vol. ii. The following papers of the Conferences of the International Fisheries Exhibition, London, 1883, also contain valuable information; - " Fish Culture," by Francis Day; "Salmon Fisheries," by Charles S. Folger; " Culture of Salmonidse," by Sir James Maitland ; "Salmon and Salmon Fisheries," by David Milne Home. For a most complete and valuable memoir on the salmon disease see the paper by Prof. Huxley, Quart. Jour. Mk. Sci.,1882. (J. T. C.)

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