Great Britain Natural History. 97 



NATURAL HISTORY. 



WHEN investigating fisheries, their present uses and the benefits which might be derived 

 from them, the inquirer soon becomes conscious of the necessity of studying many branches 

 of "natural history," both in the vegetable and animal kingdoms, without a competent 

 knowledge of which his labours will often be thrown away, or the results of his researches useless, 

 if not positively misleading. Fisheries are variously regarded by different classes ; thus the fisher- 

 man,"chiefly concerns himself as to what he can obtain from them at the present time, regardless 

 of suitable provisions for the next year's supply. The public mainly interest themselves in 

 the cost of the fish as disposed of for food ; while the scientific economist bases his conclu- 

 sions respecting the value of fisheries in accordance with their produce, and should the supply 

 be unequal to the demand he mostly advocates increased killing powers by the employment 

 of more destructive agencies, erroneously believing that the stock in the sea is inexhaustible. 

 The naturalist and fish culturist ought to approach the question from an entirely different 

 point of view ; he should ascertain the life-history of all forms of fishes, not merely such as 

 serve for human food, but also of those which form the sustenance of the more predaceous 

 kinds. He should endeavour to collect reliable information respecting the plants and animals 

 which afford them sustenance and shelter, as well as ascertain what are their enemies or 

 their friends, and what conditions favour the presence or absence of either class. Irre- 

 spective of the foregoing, he should consider the relationship of temperature, currents, soils 

 and the various conditions of the water in which they reside, to their migrations, growth 

 health, and reproduction. He should also ascertain whether fish are increasing in numbers 

 decreasing, or if the supply remains unchanged ; if the size of those captured is augmenting 

 or lessening; if their condition is better or worse than it was. Should investigations lead 

 him to conclude that fisheries are being unduly depleted, he should carefully note in what 

 families of fish such is occurring, if possible the cause, while in marine forms it is likewise 

 necessary to inquire if fishermen have to go further out to sea to obtain their captures, if 

 the killing powers of their implements have increased, and whether more men are now required 

 to obtain the same amount of fish than was the case a few years previously. Lastly, it may bo 

 observed that, unless the investigator is able to distinguish the various species, he may easily 

 imagine that he sees in some small forms, as the solonette (Solea minuta), the young of the 

 more valuable kinds, as the common sole (8. vulgaris), whereas he is merely examining one 

 sort that is worthless, except as food for the larger kinds. Our fresh-water fishes are divisible 

 into the river or " fluviatile " and the " lacustrine " or lake forms, while our marine ones may be 

 considered as shore or " littoral " and "pelagic "or sea species; these last being again sub- 

 divided into such as are generally found near the surface, at greater or mid-depths, and abyssal 

 residents, or such as live in the deep sea, below the limits to which the sun's rays penetrate. 

 Fresh-water fishes may be permanent residents therein, as carps ; " anadromous," or merely 

 visitants from the ocean for the purpose of depositing their spawn, and generally, but not 

 invariably, leaving their young to be reared there, as the salmon : " catadromous," or such as 

 reside in fresh waters, visiting the littoral zone or sea in order to breed, as eels, the young of 

 which ascend into and are reared in our rivers. To meet the destructive agencies to 

 which the eggs and young are subjected, fish are provided with a large amount of ova, 

 which is mostly sufficient to counterbalance natural waste. Thus eleven millions of eggs 

 have been taken from a 21-lb. codfish ; 550,000, from a mackerel ; 239,775, from a 4-lb. 

 brill; while a salmon deposits about 800 for every pound's weight of the parent fish. 

 Although most forms are polygamous, some are monogamous. The period of the year at 

 which spawning occurs, the size of the eggs, the depth of water in which they are deposited, 

 the time they take incubating, and the places selected for the ova are exceedingly varied. 

 The eggs of cod float in the sea until the young^ emerge, those of the herring sink to the 

 bottom, where by means of a glutinous substance they are attached to sea-weeds, rocks and 

 other objects ; those of some species of flat fishes float so long as the water is agitated, subsiding 

 when it is smooth. One form of sea-sucker (Lepidogaster) affixes its eggs to the inside of a 

 dead shell as a butterfly does to a leaf. The gar fish (l?eZoe)has filaments springing from the 

 outer covering of its ova, which enables them to adhere together in a mass or attach themselves 

 t$ contiguous substances. Anadromous forms deposit their eggs in running waters, but in 



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