XVIII REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



tiou of blue-fish, make up the most important i^art of the summer fish- 

 eries. They are still taken in great numbers by the pounds and traps, 

 although fewer than formerly, and consist in great proportion of adult 

 males and females, ripe with milt and with spawn. We can, therefore^ 

 easily understand how a most injurious influence maybe exercised upon 

 the fisheries by the capture of so large numbers under the circumstances 

 referred to. 



In all discussions and considerations in regard to the sea-fisheries one 

 important principle should be carefully borne in mind, and that is that 

 every fish that spawns on or near the shores has a definite relationship to 

 a particular area of sea-bottom; or, in other AYords, that, as far we can 

 judge from experiment and observation, every fish returns as nearly as 

 possible to its owti birthplace to exercise the function of reproduction, 

 and continues to do so, year by year, during the whole period of its exist- 

 ence. This principle underlies, as is well known, all efi:ort looking toward 

 restoring to our rivers their supply of salmon, shad, and alewives; since 

 it is well known that it is not sufficient to merel^y remove restrictions that 

 had fof years prevented the upward run of these fish, but a colony of 

 young fish must be established in the head-waters of these streams, which, 

 running down to the sea at the proper time, and returning again when 

 full}^ matured, shall fill the waters to the desired extent. 



It is an established fact tha.t salmon, alewives, and shad, both young 

 and old, have been caught on certain spawning-beds, and after being 

 properly marked and allowed to escape, have been found to re-appear 

 in successive years in the same locality. The principle is rather more 

 difficult to establish in regard to the purely marine fishes; but experi- 

 ments have been made by competent men on our coast and elsewhere, 

 which prove the existence of the same general principle in relation to 

 them. Thus, t was informed b}^ an intelligent fisherman living at Eock- 

 port, Massachusetts, that he had himself, on several occasions, marked 

 young and old halibut, and during several seasons they had been retaken 

 on about the same grounds. 



A second law, equally positive, with a great variety of fish, is that 

 they pass from their spawning-grounds to the sea by the shortest route 

 that will take them out into the deeper waters, where they spend the win- 

 ter; and that coming and going to and from a given locality, they follow 

 a determinate and definite line of migration. 



Having in mind these two propositions, we shall then better ai)pre- 

 ciate what takes place when fish are disturbed or caught up during the 

 breeding-season. Should nets be set along their line of travel before 

 they have spaw^ned, so that when they strike the coast they are imme- 

 diately arrested, first at one point and then at another, running a con- 

 tinued gauntlet of dangers in their course to their final destination ; and 

 should an appreciable i)roportion of them be caught before the eggs have 

 been laid and fertilized, it is very easy to see why the stock should 

 rapidly diminish. It is not a. sufficient argument in reply to this to 



