Ix BREEDING. 



which are' still open to discussion. Some rivers are stated to have early and 

 others late breeds of salmon. 



The same thing occurs in marine fishes.; thus there is not a month that 

 herrings cannot be found breeding around the coasts of Great Britain and 

 Ireland. " In the United States the Fishery Department has ascertained 

 that the codfish Oadus morhita breeds during nine months of the year, 

 namely, from September until May. 



Some fishes merely breed once a year, while others do so more frequently. 

 During the breeding-season a few forms, as the salmon and the shad in our 

 fresh waters, and the herrings of our seas, appear to decrease the amount 

 of food they consume or even entirely cease feeding; this may be necessary 

 in some gregarious marine forms for the following reason : Unless they 

 congregate together at this period there would be great danger in the- 

 deposited ova not being fertilized by the milt, for we know that should such 

 not take place in a short time • in fresh water they do not become vivified. 

 Should, therefore, fish in this c ndition have to be roving about in search 

 of food there would be the possibility that large quantities of eggs would 

 be spoiled, while the forms which produce the greatest number of ova are 

 often those which live in large communities. 



Whether breeding occasions any deleterious effects upon fish is capable 

 of more than one answer. Fresh-water forms that produce a moderate 

 number of eggs, or do so gradually, or at more than one period in the year, 

 do not appear to be so much affected as those which deposit large numbers 

 of ova, and complete this process in a short space. As a rule, the result 'of 

 breeding is that the parent fish goes out of condition, and continues so for 

 a longer or shorter period of time. Herrings, as soon as they are " spent," 

 fall off in condition ; the salmon kelt becomes absolutely unwholesome, or. 

 else so lean and flabby as to be unsuitable for the table. 



Fishes' eggs are 'of various sizes, and this size is not in relationship 

 to the magnitude of the species — thus • a codfish has much smaller 

 eggs than a trout, and a common carp than a char. While some forms 

 deposit their ova in the sea, others- do- so in fresh-water, which may be 

 stagnant, semi-stagnant, or running. Some eggs are so light that 

 under certain conditions they may float, as of the cod in the sea,, 

 while those of the white-fish Goregonus are semi-buoyant, and those 

 of the herring sink: those of the gar-fish and its allies are attached by 

 filaments or tendrils to foreign substances, while others are likewise 

 adherent, due to a secreted mucus, as in the lump sucker (Liioaris), which 

 deposits its ova on the inside of the valves of dead shells, as a butterfly does 

 on a leaf ; while the fresh-water bitterling, Rhodeus amarus, of Continental 

 Europe is furnished during the breeding season with a long oviferous tube 

 enabling it to insert its eggs within the valves of the fresh-water mussel. 



