PACIFIC SALMON 



Oncorhynchus 



At one time or another each of the five Pacific salmon has been introduced 

 into the waters of Maine. At the present time only the silver salmon {Oncor- 

 hynchus kisutch) is being reared and planted in the streams and lakes. Aside 

 from the large size of the Pacific salmon at maturity the greatest difference be- 

 tween the salmon and trout is one of habit and not structure. For example the 

 Pacific salmon die after spawning. Since we are interested in the fishes found 

 in the fresh waters of Maine it will be convenient to divide the Pacific salmon 

 according to their fresh-water habits. 



The first group, the king {Oncorhynchus tshwaytschd) and the silver sal- 

 mon {Oncorhynchus kisutch^ furnish the best sport fishing of the entire group. 

 These two are characterized by the young remaining in fresh water for a year 

 or two. 



King salmon, averaging 20-25 pounds in weight and three feet in length, 

 is the largest of the Pacific salmon. These run the streams in the spring and fall 

 with all spawning in the fall. The young remain in the streams for a year or two 

 at which time they are frequently taken for trout by anglers. Migrating to salt 

 water they reach their large size and maturity there, returning at an average age 

 of four years to spawn and die completing their life history. King salmon were 

 planted in Damariscotta Lake and Long Lake in 1 940 and in Pemaquid River 

 in 1941. Any of these fish would of course be dead and gone by now. In 1937 

 adult king salmon were observed migrating down out of Cobbosseecontee Lake 

 for about one-half mile into the outlet where they were stopped by a permanent 

 screen. At about the same time eight dead females examined had recently 

 dropped their eggs. Eggs retained in the ovaries showed that they could de- 

 velop normal-sized eggs while being confined in this fresh-water lake. Natural 

 reproduction has not been successful when the fish have been confined to fresh 

 water. Best success from king salmon plantings in Maine has been in Swan and 

 Damariscotta Lakes. In these two lakes the king commonly attained a weight 

 of 6 to 10 pounds. 



The silver salmon, averaging about 9 pounds and up to 2^4 feet in length, 

 ranks third in size of the Pacific salmon. Silver salmon commonly spend one 

 summer in the stream and two in the ocean. Most of them return when they are 

 three years old. Adults ascend the rivers just prior to spawning and may use 

 rivers that do not have the deep pools necessary to carry over the Atlantic salmon. 

 The Atlantic Salmon Commission of Maine has scheduled plantings of silver sal- 

 mon in the Ducktrap River, Chandler River, and Tunk Stream. These fish pro- 

 vide excellent sport fishing in the estuaries of the Pacific coast streams, and should 

 provide an additional sport fishery for Maine. 



The next two salmon are classified together because their young migrate 

 directly to the sea on hatching, spending little or no time in fresh water. Since 



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