EVALUATION OF CAUSES FOR THE DECLINE 

 KARLUK SOCKEYE SALMON RUNS A 

 RECOMMENDATIONS FOR REHABILITA 



Richard Van Cleve^ and Donald E. Bevan^ 



ABSTRACT 



^. 



The continued decline of the Karluk River sockeye salmon, Oncoihynchus ncrka, runs in- 

 dicated the need for review of their condition. We reviewed the literature on the Karluk 

 sockeye salmon and the different explanations for their decline. Unpublished material from 

 the Auke Bay Fisheries Laboratory, National Marine Fisheries Service, was studied along 

 with published and unpublished observations of Karluk sockeye salmon by the Fisheries 

 Research Institute. Recent reports showing the behavioral differences between fry from one 

 of the side streams and from the Karluk River, combined with studies of the genetic basis of 

 similar behavioral differences in Fraser River sockeye salmon populations indicate that the 

 sockeye salmon of the Karluk system are separated into a number of different races. The 

 spawner-recruit relationship was examined over the 50 yr during which the numbers of 

 spawners and resulting returns have been estimated. The combination of all evidence includ- 

 ing peculiarities of sockeye salmon life history, derived from the work of the International 

 Pacific Salmon Fisheries Commission on the Fraser River, and from the material on the 

 Karluk, leads to the conclusion that the Karluk River below Karluk Lake is the largest and 

 most productive spawning area in the system. We conclude that the productivity of the 

 races spawning on these grounds could be restored by removal of all weirs from the Karluk 

 system, by restricting the study of these fish in freshwater to methods which do not involve 

 interfering in any way with the free movement of adults or young, and by protecting the 

 adult Karluk sockeye salmon that move through the fishery in midseason, i.e.. during July 

 and August each year. 



The year 1973 marks the 53d year since a weir 

 was first installed on the lower end of the Kar- 

 luk River by the U.S. Fish Commission to count 

 the number of sockeye salmon, 0)icorhyiiclu(s 

 nerka, which escaped the commercial fishery to 

 spawn in the Karluk watershed. While sporadic 

 observations of the fishery and of the spawning 

 grounds had been made before then, a program 

 of management was established in 1921 to as- 

 sure the escapement of an adequate number of 

 spawners. Gilbert and Rich (1927) began more 

 frequent visits to the spawning areas after 1921 



' Contribution No. 379, College of Fisheries, University 

 of Washington, Seattle, Wash. 



^ College of Fisheries, Universitv of Washington, Seattle, 

 WA 98195. 



•■' Fisheries Research Institute, College of Fisheries, 

 University of Washington, Seattle, WA 98195. 



which were extended in 1927 to annual surveys 

 lasting from about May to September each year. 

 Beginning shortly after 1900, a decline was 

 noticed in the numbers of sockeye salmon re- 

 turning each year to the Karluk, which was re- 

 flected in the annual catch. This decline has 

 continued in spite of the increasing severity of 

 restrictions imposed on the fishery to allow a 

 greater proportion of the run to spawn. In 1971, 

 the fishery was closed although an incidental 

 catch of 14,000 Karluk sockeye salmon resulted. 

 Nevertheless, only 144,660 sockeye salmon es- 

 caped through the weir. Using the factor of 10% 

 of the total run used by the Auke Bay Fisheries 

 Laboratory staff of the National Marine Fish- 

 eries Service (NMFS), NOAA. since 1963 to 

 estimate the numbers spawning in the Karluk 

 River below the weir, the total run that year 

 must have been about 175,000 fish, the smallest 



Manuscript accepted February 1973. 

 FISHERY BULLETIN; VOL. 71, NO. .3, 1973. 



627 



