of G. breve is discussed. G. breve were found with- 

 in the temperature range 13.8° to 30.6° C. It was 

 absent or rare at both the low and high temper- 

 atures; cell densities greater than 1,000 per liter 

 were observed from 26.0° to 27.9° C. The organism 

 occurred at salinities ranging from 33.68 to 37.07 

 p.p.t. The highest concentration of cells and inci- 

 dence was noted within the salinity range 35.00 to 

 .36.90 p.p.t. 



542. Some effects of DDT on the ecology of 

 salmon streams in southeastern Alaska. By 

 Roger J. Reed. November 1966, iii -f- 15 pp., 

 7 figs., 9 tables. 



ABSTRACT 



The effects on stream-dwelling fish and insects of 

 an aerial application of PDT (0.28 kg. (kilogram) 

 per hectare or one-fourth pound per acre) to control 

 blackheaded budworm were studied in four .streams 

 in southeastern Alaska. 



Prespray and postspray sampling was done to 

 determine the food eaten by rainbow and cutthroat 

 trout, the coefficient of condition of trout, the abun- 

 dance of insects on stones in the stream, the numbers 

 of drifting insects, and the concentrations of DDT 

 in the water, fish, clams, and plankton. 



The effects of the DDT were an immediate marked 

 increase in the number of aquatic insects drifting 

 in the stream the day of spraying and the annihila- 

 tion of aquatic insects within 3 days . No fish were 

 observed to be harmed, although the concentrations 

 of DDT and DDE (biological derivative of DDT) 

 in their bodies increased. The concentrations of 

 DDT also increased in stream waters, plankton, and 

 clams. The one known long-term effect of the DDT 

 on trout was a decline in their condition factor, ap- 

 parently due to the reduction in their food supply. 



The stream insects slowly began to reappear a 

 few weeks after the spraying but did not approach 

 normal numbers until the following summer. 



AUTHOR INDEX 



Ahlstrom, Elbert H., S 534 



Allen, Donald M., and T. J. Costello, D 11 



Amos, Murray H., C 237 



.■\nas, Raymond E. — see Roppel et al. 



Anderson, William W., PL 589 



Anderson, William W., Jack W. Gehringer, and 

 Frederick H. Berry, C 245 



Anonymous, C 250, PL 581, PL 584, PL 591, PL 593, 

 PL 595, PL 596, PL 597 



Barnett, Harold, and Richard W. Nelson, FIR v. 3, p. 13 



Berry, Frederick H. — see Anderson et al. 



Blackburn, Maurice, S 540 



Broughton, John H. — see Zimmer and Broughton 



Bullis, Harvey R., Jr., and John R. Thompson, C 236, 

 C 249 



Butler, Philip A., C 247 



Cable, Louella E., PL 583 



Carroll, Bobby J., Travis D. Love, Benjamin Q. Ward, 

 and Melvin E. Waters, FIR v. 3, p. 5 



Chapman, Douglas G. — see Roppel et al. 



Chapman, Wilbert McLeod, C 250 



Chase, Joseph, D 10 



Cheek, Randall P. — see Nichols and Cheek 



Chin, Edward — see Inglis and Chin 



Costello, T. J. — see Allen and Costello 



Dragovich, Alexander — see Finucane and Dragovich 



Dragovich, Alexander, and John A. Kelly, Jr., S 541 



Dragovich, A., J. A. Kelly, Jr., and J. H. Finucane, D 13 



Earle, Wendell — see Frohman et al. 



Echaniz, R., Jorge, C 250 



Parragut, Robert N., and Mary N. Thompson, FIR v. 3, 

 p. 1 



Finucane, J. H. — see Dragovich et al. 



Finucane, John H., and Alexander Dragovich, D 14 



Floyd, Hilton M., PL 586 



Frohman, .\rthur H., John Mehos, Eric Turnill, and 

 Dr. Wendell Earle, C 250 



Gehringer, Jack W. — see Anderson et al. 



Gillaspie, Charles C. — see Patten and Gillaspie 



Henry, Kenneth A., C 240 



Higham, Joseph R., Jr. — see Nicholson and Higham 



Hile, Ralph, S 528 



Inglis, Anthony, and Edward Chin, PL 582 



10 



