44 



THE MIGRATION AND CONSERVATION OF SALMON 



is necessary, until there are facts to prove 

 that the stock is endangered. 



The matter of maintaining the stock or 

 actually increasing it is best handled by 

 work in the rivers. For any particular 

 river we should ascertain what suitable 

 spawning beds are available, whether there 

 are sufficient spawning salmon to utilize 

 them properly, whether the young from nat- 

 ural spawning make proper use of the food 

 available for them, and how the death of 

 the young from enemies, disease, and physi- 

 cal or chemical causes can be prevented. 

 Conservation of the maturing fish will be 

 clearly advisable only when the numbers of 

 spawning fish are found to be insufficient 

 for proper utilization of the river 's capabil- 

 ities for natural smolt production. 



Summary 



1. The facts indicate a sea distribution 

 of the salmon of the St. John River only as 

 far out as about 50 miles from the river 

 mouth into the Bay of Fundy, within which 

 they are taken half-way toward becoming 

 grilse. Tagged maiden fish remain within 

 the zone of river influence and show no 

 steady movement riverward, but movement 

 outward as well as inward. 



2. Tagged kelts, when liberated outside 

 the mouth of the St. John River, showed a 

 later distribution predominantly inward in 

 contrast to that of the maiden fish. Those 

 liberated in the estuary of the Northwest 

 Miramichi River were later recaptured even 

 farther inward in contrast with the maiden 

 fish. 



3. There is strong evidence that salmon 

 are passively transported in the sea even to 

 very great distances. Where river influ- 

 ence is slight and intermittent as for the 

 Margaree River, Cape Breton Island, the 

 salmon are widely scattered. 



4. More rapid movement to distant 

 places, which tagging experiments show, is 

 explicable as resulting from the fish being 

 farther out from the shore, in more rapidly 

 moving water and away from turbulent 

 current, in which they cease to wander. 



5. Ascent or descent of a river by the sal- 

 mon at any stage is seen as being variable 

 and dependent upon its condition and upon 

 the conditions surrounding it, and not upon 

 its ability to achieve a purposeful migra- 

 tion. 



6. The necessity for the conservation of 

 the salmon stock of any river should be 

 established before restricting its exploita- 

 tion by man. 



Eeferences Cited 



Huntsman, A. G. 1933. Heat and Cold Make 

 Herring Seasons in Passamaquoddy. Atl. Progr. 

 Bep. Biol. Bd. Can., 7: 3-6. 



. 1924. Circulation and Pollution of 



Water In and Near Halifax Harbour. Contr. 

 Canad. Biol. N. S., 2: 69-80. 



Menzies, W. J. M. 1937. The Movements of Sal- 

 mon Marked in the Sea. I. The North-west 

 Coast of Scotland in 1936. Fish. Scot. Salmon 

 Fish., 1937, I, 1-17. 



. 1938. The Movements of Salmon 



Marked in the Sea. II. The "West Coast of 

 Sutherland in 1937. Fish. Scot. Salmon Fish., 

 1938, I, 1-9. 



White, H. C. 1936. The Homing of Salmon in 

 Apple Elver, N. S. J. Biol. Bd. Can., 2 : 391-400. 



