(one-fourth mile) above its mouth, and has 

 very limited spawning area. It has small 

 escapements of pink, chum, sockeye, and 

 coho salmon; the lower lake contains cutthroat 

 and rainbow trout. 



Virginia Creek is about 1.6 km. (1 mile) 

 long and includes a small boggy lake. The 

 stream has a few rainbow trout, and the lake 

 has resident cutthroat trout. A few pink 

 salmon spawn in the lower end of the stream, 

 and coho salmon spawn near the lake. 



Old Franks Creek, located between Virginia 

 and Cabin Creeks, was used as a source of 

 test fish. In addition, samples of water and 

 fish were collected from Old Franks Creek 

 to detect drifting of spray material from the 

 test watersheds. 



COLLECTION OF SAMPLES 



Fish, aquatic insects, and water samples 

 were collected from the four streams, and 

 clams and plankton were collected near the 

 stream nnouths before and after spraying. 



Fish 



Fish were collected by gill netting in the 

 lakes and by hook-and-line fishing and seining 

 in the streams. They were preserved in 

 10 percent formalin except those used for 

 DDT analysis, which were frozen. After at 

 least 2 days preservation, weight (to the 

 nearest 0.1 g. (gram)), total and fork lengths 

 (to the nearest millimeter), and sex were 

 determined for each fish. Stomach contents 

 were removed, and the percentage of the total 

 volume contributed by each of 1 5 categories 

 of food was estimated by the visual method 

 (McCormick, 1940; Raney and Lachner, 1942). 



Fish were collected only from the streams 

 between tidewater and the first lake except 

 in the Virginia Creek system where some 

 fish were taken from Virginia Lake because 

 of the scarcity of fish in the creek. Four to 

 six rainbow trout were taken from Old Tonn, 

 Cabin, and Saltery Cove Creeks. They ranged 

 between 110 and 160 mm. (millimeters) in 

 total length and between an estimated J'20 and 

 -TSO g. in weight. Cutthroat trout were taken 

 from Virginia Lake (4 to 6 specimens). They 

 ranged between 125 and 200 mm. in total 

 length and an estimated t^©- and tIOO g. in 

 weight. '^•> 



JS 



Aquatic Insects 



The "stone" sample method (Cope, 1961) 

 was used to index the abundance of aquatic 

 insects. This method consists of removing 

 stones about 15.2 cm. (centimeters) in diam- 

 eter from a riffle and counting the attached 

 insects. In this study, 20 stones were selected 

 from each of two riffle areas in each stream. 



and Diptera and Ephemeroptera, the most 

 abundant orders, were counted. Sample sites 

 were within 275 m. of the high-tide level. 

 The abundance of insects was determined 

 weekly from June to September, beginning 

 in August 1961. To avoid killing or dislodging 

 the insects, I handled and replaced the stones 

 in the stream with care. Beginning in 1962, 

 numbered plastic tags were wired to each 

 stone so that individual stones could be ex- 

 amined repeatedly. When tagged stones dis- 

 appeared (probably because of floods or salmon 

 spawning), they were replaced by other stones 

 from the stream. 



Drifting aquatic insects were sampled with 

 a Surber square-foot bottonn sampler held on 

 the bottom facing into the current for 5 min. 

 (minutes). They were preserved in 37 percent 

 isopropanol. 



Water Samples 



Selected water properties were determined 

 for each stream weekly throughout the summer 

 seasons. All samples (1 qt. (quart) of water 

 constituted a sample) were taken within 275 m. 

 of the high-tide level. A Hach"' colorimeter 

 was used to determine pH, turbidity, and 

 oxygen; the methyl-orange method was used 

 to calculate total alkalinity. The waters of all 

 the streams were similar- -pH values were 

 close to 7, total alkalinity ranged from about 

 2 to 45 p. p.m. (parts per million), turbidity 

 ranged from to 60 p.p.m., and oxygen values 

 were generally near saturation. Water tem- 

 peratures and stream levels were recorded on 

 continuously operating instruments. 



Series of samples were taken from the 

 surface water on the days of spraying and 

 before and after spraying to test for the 

 presence of DDT. The samples were placed 

 in vacuum bottles or glass mason jars to 

 which a few drops of dilute sulfuric acid were 

 added to prevent breakdown of the DDT. On 

 the "spray days," water was collected at 

 2-hr. (hour) intervals. In addition to the sur- 

 face samples, intragravel water was collected 

 from Old Tom and Cabin Creeks before and 

 during the day of spraying. Rigid plastic 

 pipes about 2.5 cm, in diameter were driven 

 about 25.4 cm, into the gravel, and samples 

 were withdrawn from the bottom of the pipes 

 with a long syringe. 



Marine Clams and Plankton 



Several common species of marine clams 

 were dug from beaches in the vicinity of each 

 study stream in 1963 both before and after 

 spraying. Seven to eight clams were dug at 

 each site. The samples (150 g. of material) 

 were frozen and later tested for DDT. 



^ Trade name referred to in this publication does not 

 imply endorsement of commercial product. 



