Because of low ground-water dissolved oxy- 

 gen, Indian Creek (and probably many other 

 streams in Southeastern Alaska and else- 

 where) apparently differs from spawning areas 

 in which the presence of ground water has been 

 reported to affect beneficially spawning of 

 adult salmonids and survival of their eggs 

 and larvae. White (1930), Greeley (1932), 

 Hazzard (1932), and Benson (1953) all stated 

 that the presence of springs and of ground- 

 water seepage determined the location of 

 spawning areas of brook and other species 

 of trout. Benson also said that ground-water 

 seepage affected both sizes and numbers of 

 all age groups of brook and brown trout in 

 the Pigeon River, Mich. 



Association of sockeye salmon spawning 

 with ground water has been mentioned by 

 Burgner (1958), and Mathisen (1955) for Bristol 

 Bay, Alaska, and by Krogius (1951), Krokhin 

 and Kurenkov (1954), Krogius and Krokhin 

 (1948), and Kurenkov (1957) for the Kamchatka 

 Peninsula. Royce (1951) found no evidence 

 that lake trout select a lake bottom supplied 

 with spring water for deposition of their eggs. 



Results of temperature and dissolved oxygen 

 measurements of water in the gravel bar of 

 the study riffle in Indian Creek furnish indi- 

 cations as to whether or not a gravel bar is 

 a favorable environment for developing salmon 

 eggs. In almost every stream suitable for pink 

 salmon spawning in Southeastern Alaska, there 

 are extensive gravel bars (termed marginal or 

 fringe spawning areas) on which heavy spawn- 

 ing sometimes occurs when stream level and 

 population pressure are high. In Cabin Creek 

 I determined that spawning in a cross section 

 of a riffle increased by 50 percent with a 

 rise in stream level of 1.1 feet (gage height 

 from 0.48 to 1.58 feet). Since salmon eggs 

 and larvae that are developing in marginal 

 spawning areas are subject to fluctuating 

 stream heights and are often exposed to pro- 

 longed periods of low air temperatures, their 

 chance for survival would appear to be low. 

 Hunter (1959) reported that in some years 

 spawning in fringe areas showed greater 

 survival ratios than spawning in other areas 

 in Hooknose Creek, British Columbia. He 

 attributed high survival years to relatively 

 constant water levels and absence of persistent 

 freezing temperatures. 



Since salmon eggs deposited in certain parts 

 of the marginal spawning area in the Indian 

 Creek study riffle would be subject to inter- 

 mittent high temperatures and low dissolved 

 oxygen levels, this does not appear to be a 

 favorable environment for survival. 



SUMMARY 



Part of study conducted by the Fisheries 

 Research Institute on effects of logging in 

 southeastern Alaska salmon spawning streams 

 was an investigation of waterflow through the 

 gravel of a spawning riffle in Indian Creek. 

 This investigation included a determination 

 of (1) dissolved oxygen content and temperature 

 of ground water and the extent of ground- 

 water seepage, (2) variation of dissolved 

 oxygen content of water with depth in the 

 streambed, (3) interchange of flowing stream 

 water and water of the streambed gravel, and 

 (4) flow characteristics of water in the gravel 

 of streambank and gravel bar. 



Through tracing flow directions with fluo- 

 rescein dye and measuring the dissolved oxygen 

 content and temperature of stream and ground 

 water, we found the following: 



1. Ground water was low in dissolved oxygen 

 at all times of the year except the winter 

 months when ground- water temperatures were 

 lowest. 



2. Ground-water temperatures were lower 

 than stream temperatures during the summer 

 and higher during the winter. 



3. Dissolved oxygen content of water within 

 the gravel of the streambed decreased with 

 depth. 



4. Ground water flowed from the streambank 

 into the streambed. Its presence was detected 

 by its dissolved oxygen and temperature dif- 

 ferences. 



5. The major source of water of high 

 oxygen content within the gravels of the 

 riffle was the stream. This was determined 

 by demonstrating large-scale interchange in 

 the main stream and by measuring dissolved 

 oxygen content and temperatures of water 

 in the gravel of a gravel bar with inter- 

 mittent surface flow. 



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