CANADIAX FIRHERIEH EXPEDITIOX, lDl.'ri5 33 



III. DISTRIBUTION OF EGCiS AND YOUXG IN THE WATERS 



INVESTIGATED. 



It is a well-known fact that certain species have their more or less definite 

 spawning grounds, or, at any rate, are to be found during the spawning season, at 

 places where certain physical conditions prevail, these conditions being, presumably, 

 such as are best adapted to the propagation of the species in question. 



When spawning, our most important food fish assemble upon grounds of restricted 

 area, where they can naturnllv be tnkeii in the creatoit iiumber: it i=; therefore of 

 considerable importance, for the fisheries, to ascertain the position and extent of 

 such grounds. This may be done by making experimental hauls to secure the spawning 

 fish, or, far more easily, by plankton hauls, from the results of which it will be seen 

 where the newly spawned eggs and young are to be found, whence we can determine 

 the locality of the spawning grounds. This latter method has been largely employed 

 in the international investigations in European waters, and has led to the charting of 

 the spawning grounds of the dift'erent species. 



If we now consider the results of the various cruises in Canadian waters, it 

 will soon be seen that the eggs and young of each species have one or more principal 

 areas of distribution, diminishing in frequency to either side of such area; further, 

 that certain species generally occur together, others again being invariably found apart. 



This distribution is dependent upon the diiferent circumstances under which the 

 fish spawn, and we shall see that each species is always encountered under certain 

 conditions, wherefore a certain degree of regularity may be shown to exist in their 

 occurrence. The eggs and young of littoral fish are found close to land, or over the 

 shallow banks; the banks have their own particular young-fish fauna, and the deeper 

 parts, again, theirs. To these must be added a fourth group, to wit, that of the 

 pelagic species, such as the mackerel; in the case- of these, the question of depth is 

 less important, and their eggs may therefore be found scattered throughout all areas, 

 where they may be taken together with the ova of the three first groups. An interesting 

 phenomenon, however, is the fact that both eggs and young of practically all our 

 principal species of fish have a pelagic stage, during which they are to be found near 

 the surface, without regard to whether they were spawned there or at greater depths. 

 In the case of most species, both eggs and young are so balanced as to float in ordinary 

 sea- water, and when spawned deep down will, owing to their own buoyancy, rise to 

 the surface, where their development then proceeds. The young will thereafter, as 

 their growth advances, again move down to greater depths, or in towards land, passing 

 from a pelagic habit of life to a more or less pronounced bottom stage. 



A. The Gulf of St. Lawrence. 



The various cruises furnish a number of instances showing how the character of 

 the fauna changes as we pass from the vicinity of the coast outwards, or from colder 

 to warmer waters, and vice versa. 



As already mentioned, the gulf St. Lawrence was investigated by the Princess, 

 June 9 to June 15 and August 3 to August 12, with some occasional work done by the 

 No. S3 from June 1 to August 18; this latter cruise may be disregarded in the present 

 chapter, both on account of the length of time covered, and also because the voyage was 

 not planned according to the special lines of our present purpose. The route followed 

 on such cruises is, it should be noted, of great importance both for the investigation 

 of the different localities, and also for the collective survey of the waters as a whole. 



The cruises of the Princess (vide chart, p. 4) both proceeded from Prince Edward 

 Island over to the eastern point of Anticosti, continuing up to Labrador, and thence 

 eastward to Newfoundland, then following the coast southward, past Cape Breton, and 

 bade to Prince Edward Island. Glancing now at the hauls inade at the different 



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