ICHTHYOLOGY. 



685 



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clusively in fresh water, when confined in a lake or ri. 

 ver. We are informed in the statistical account of the 

 parish of Lisrnore, when speaking of the fresh water 

 lakes of that island, (Stat. Ace. vol. i. p. 485. ) " That, 

 mbout 50 or 60 years ago, there were some sea trouts 

 carried to these lakes, the breed of which preserve their 

 distinction perfectly clear to this day. They retain 

 Uieir shining silver scales, though they have no com- 

 munication with the sea ; their flesh is as red as any 

 salmon, and their taste is totally different from that of 

 the yellow trouts." 



The circumstance of some fish being capable of living 

 either in fresh or salt water, has suggested the idea of 

 attempting to modify the constitution of salt water 

 fishes, so as to enable them to subsist in fresh water. 

 If the change is attempted to be produced in young 

 fish bjr degrees, and with caution, the experiment may 

 prove successful, especially with those fish that reside 

 chiefly near the Mm shore. But in the case of fishes 

 which live in deep water, a change not only in the re- 

 spiratory organs must be produced, but likewise in 

 those of digestion, as they must subsist on a new kind 

 of food. We regard such experiments as curious, but 

 can scarcely bring ourselves to believe, that they will 

 be productive of advantage to society. In attempting 

 to improve our fisheries, we should prefer the prudent 

 advice of Virgil to the dreams of the theorist et quid 

 q**peffi*t rerio, et quid quaque reetuel. 



We ppueu but few accurate observations on the 

 distribution of fishes, with respect to temperature. 

 Living in an element subject to little variation from 

 the change of the seasons, fishes, like sea- weed*, have an 

 extensive range of latitude a* well as longitude through 

 which they roam. But they appear to abound in the 

 greatest variety of species in the equatorial region-., 

 and to diminish in numbers with regard to species as 

 we approach the poles. In this country we may ob- 

 enre a certain arrangement of some of the species with 

 respect to latitude. Thus the fresh water fishes of 

 England are much more numerous than those in ! 

 land. In the sea at the south of England, the pilchard 

 is found in abundance, while it is rare in Scotland. In 

 the seas in the north of Scotland, the tusk (Gadus 

 broime) abounds, in the south of Scotland it is very 

 rare, and in England it is unknown. 



While some fishes living in the northern seas, or in 

 alpine lakes, seem to prefer cold water, there are fish 

 which appear to dwell even in the waters of tepid 

 soring*. La Cepede informs us that Desfontaines found 

 the Spam DttfoHiamei in the warm waters of the two 

 fountains which supply the town of Cassa in the king- 

 dom of Tunis. The waters raised Reaumur's thermo- 

 meter 30 above the freezing point, or about 1 00 of Fah- 

 renheit. The waters contained no mineral impregna- 

 tions, and when cooled, were used by the inhabitants. 



r. 1 1. Migration of Fishes. 



TNOH fishes which enter rivers for the purpose of 

 pawning, peifutiu their migrations annually, but do 

 not appear at any venr precise period. Their motions 

 appear to be regulated by the condition of their gene- 

 rative organs, aad these are in their turn confronted by 

 the temperature of the water in which the fishes remain, 

 or the supply of food. In rivers where salmon spawn, 

 it is obstruct! that these fish continue entering the river 

 for the space of seven or eight months. Those marine 

 fishes, such a* the herring, pilchard, and many others 

 which leave the deep water, and approach the shores 



for the purposes of spawning, are equally irregular Condition 

 with respect to their periods of appearing and disap- of Fis hes. 

 pearing. '-Y'' 



Besides these movements, which depend on the ge- 

 nerative impulse, many marine fishes appear to mi- 

 grate from one shore to another, influenced by laws 

 which have never been satisfactorily explained. Thus 

 haddocks have been known to visit a coast for many years 

 in succession, and then suddenly to disappear, and at 

 the same time all those predaceous fish which fed upon 

 them. Perhaps these movements may depend upon the 

 supply of food, and be regulated by circumstances over 

 which we can exercise no controul. Accurate observa- 

 tions, however, would probably ascertain the limits of 

 these migrations, and enable us to derive advantage 

 from motions which at present we regard as calami- 

 tous. 



In the summer season, all the fresh water fish are ac- 

 tive and lively ; but during the winter, many species 

 bury themselves in the mud, and, in a state of quies- 

 cence similar to natural sleep, outlive the vicissitudes of 

 that variable season. While active they require a copi- 

 ous supply of food ; but in this state' of hybernation 

 they continue fasting, and without inconvenience. 



SECT. III. Education of Fishes. 



THE element in which fishes reside, removes them so Education 

 far from our influence and observation, that it is diffi- of fishes - 

 cult to estimate the amount, or the qualities of the im- 

 material principle which they possess. We witness 

 them fly from danger, obey the impulse of appetite, and 

 provide a suitable place for the eggs of their future off- 

 spring. These, however, are in general regarded as 

 the lowest marks of mind, or as mere blind instinctive 

 motions. 



Fishes, we have seen, possess in a greater or less de- 

 gree of perfection all those external senses, by means 

 of which the other animals acquire a knowledge of ex- 

 ternal objects. Hence we find that they speedily be- 

 come acquainted with the hand that feeds them, and 

 know the face of a stranger. They may be taught to 

 come to the edge of a pond when called by their usual 

 name, or to assemble at the sound of a bell. Baster 

 even informs us of a trout, which had been kept four- 

 teen years and seven months, which would come and 

 repose on the hand of its master while he removed the 

 water of the vessel in which it was kept. 



That they possess some powers of deliberation, ap. 

 pears evident from the artifices which they employ to 

 escape from the nets in which they have been inclo-ed, or 

 from the hook which they have incautiously swallowed. 

 Salmon have been known to lie close on the ground in 

 some hollow place, to permit the net to pass over them, 

 or by a sudden spring to leap out of the net. The fishing 

 frog, or angler, as it is also called, (Lophius piicntorius,) 

 has two long tentacula on the head, resembling in ap- 

 pearance small worms. Having buried its body in the 

 sand, leaving only these tentacula exposed, it moves 

 them backwards and forwards, until the eye of some 

 young fish is attracted by the deceitful appearance, and 

 falls a prey to its lurking foe. 



With regard to their social instincts, fishes present 

 very remarkable differences. Some are gregarious at 

 all seasons, while others are solitary unless during the 

 breeding season. The sexual union is merely tempo- 

 rary, and no feelings of affection subsist between the 

 parent and the offspring. Indeed the life of a fish is one 

 continued scene of suspicion and fear, no leisure being 

 left for the improvement of its faculties. Hence we are 



