VREELAND ET AL.: HOMING BEHAVIOR OF MARKED COHO SALMON 



1965, the fishing area extended from Battle Creek 

 slough to the old Highway 101 bridge (Figure 1). 

 The open area was extended to the new Highway 

 101 bridge in 1965. Coho salmon is the main species 

 caught, but some chum salmon, 0. keta, chinook 

 salmon, 0. tshawytscha, and steelhead trout, Sal- 

 mo gairdneri, are also taken (Weiss 1966). The 

 coho fishery has fluctuated from a low of 2,100 

 adults in 1962 to a high of 31,600 adults in 1967.-^ 



The sport fishery in Youngs Bay itself is very 

 limited. A majority of the sport fishing occurs 

 from the confluence of the North and South forks 

 of the Klaskanine River upstream to the 

 Klaskanine Salmon Hatchery. A minor sport 

 fishery for coho salmon exists on the Youngs 

 River. It is limited by an impassable falls a short 

 distance upstream from the river's confluence with 

 Youngs Bay. There is little or no sport fishing for 

 salmon on the Lewis and Clark or Walluski rivers. 

 Sport fishing for coho in Youngs Bay and its 

 tributaries starts after the first fall rains, from 

 mid-September to the first of October.' 



METHODS AND MATERIALS 

 Source of Fish 



Coho salmon were selected as the test species for 

 this study because of the success of hatchery coho 

 culture exhibited by large hatchery returns. The 

 coho for this experiment were obtained from Lit- 

 tle White Salmon National Fish Hatchery. The 

 eggs were taken in 1968 at Klaskanine Salmon 

 Hatchery, and 926,300 were shipped to Little 

 White Salmon Hatchery for hatching and rearing. 

 Eggs from coho returning to Little White Salmon 

 Hatchery were not reared at the station because 

 the stock was considered undesirable. This stock 

 had inadvertently been selected to commingle 

 with the hatcheries fall chinook returns. This made 

 it difficult to retain coho in good condition until 

 spawning time. The Klaskanine coho were a later 

 returning stock and would presumably eliminate 

 the conflict with fall chinook. 



Little White Salmon Hatchery is located near 

 Cooks, Wash, on the Little White Salmon River 

 approximately 1.5 km (1 mile) upstream from its 

 confluence with the Columbia River and is about 



242 km (150 river miles) from the Pacific Ocean. 

 The hatchery is operated by the U.S. Fish and 

 Wildlife Service and is funded primarily by the 

 National Marine Fisheries Service. 



Marking 



The marking portion of the study took place in 

 March 1970. A total of 201,700 1968-brood coho 

 salmon were marked with a finclip at Little White 

 Salmon Hatchery. The right ventral (RV) fin was 

 removed from 100,809 coho which were to be 

 released in the Little White Salmon River. The left 

 ventral (LV) fin was removed from 100,914 fish 

 which were to be released into Youngs Bay. Fish 

 were 55-62/kg (25-28/pound) at time of marking. 



Release Procedures 



Youngs Bay was selected as a release site for 

 three reasons. First, the bay is within the Colum- 

 bia River system and yet a great enough distance 

 from the Little White Salmon Hatchery to 

 examine homing characteristics of coho salmon. 

 Second, the bay provides a specific area separate 

 from the Columbia River to which the salmon 

 could home. Finally, the intensive commercial 

 fishery in the bay was somewhat separate from the 

 Columbia River fishery and would be relatively 

 easy to sample. 



A total of 100,662 LV-marked coho salmon 

 weighing 2,019 kg (4,451 pounds) or 49.8 fish/kg 

 (22.6/pound) were transported from the Little 

 White Salmon Hatchery to Youngs Bay on 23, 27, 

 and 29 April 1970. This was the normal historical 

 coho release time at the hatchery. Two hatchery 

 tank trucks, each making one trip per day, were 

 used to transport the fish. On the first trip the 

 water in the trucks was iced to maintain a con- 

 stant temperature during transportation. The 

 weather was rainy and cold, and the result was 2°C 

 lower water temperature in the trucks than in the 

 bay. Bay water was added to the tanks to equalize 

 the two temperatures. The weather was the same 

 on ensuing trips so icing was discontinued. The 

 dates and water temperatures at the time of 

 release are as follows: 



Temperature (°C) 



yames L. Galbreath. 1968. Youngs Bay commercial coho 

 fishery in 1967. Fish Comm. Oreg., Fish Comm. Res. Lab., 

 Clackamas, Oreg. (Unpubl. manuscr., 10 p.) 



'Franklin R. Young. Fish Comm. Manage. Res. Hdqrs., 

 Clackamas, Oreg. (Pers. commun.). 



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