HOLDING PONDS FOR ADULT SALMON 



INTRODUCTION 



Artificial propagation of salmon ( Oncor- 

 hynchus) can be complicated by the variations 

 encountered in the migration patterns of the 

 several species, races within species, and even 

 individuals within races. The freshwater migra- 

 tion of adult Pacific salmon is divided into two 

 phases, the first is the upstream migration to 

 location, and the second is the spawning migra- 

 tion or search for a spawning site. The interval 

 between these migrations may be but a few hours 

 or as much as three or four months . 



The problem is to secure the adults in 

 sufficient numbers to meet the requirements of 

 artificial propagation without incurring pro- 

 hibitive mortalities . With different migration 

 patterns different solutions are available. When 

 the interval between the upstream and spawning 

 migration is short, the fish may be trapped on 

 the upstream migration and held either in the 

 stream or improvised ponds until sexually 

 mature without prohibitive mortalities . When 

 the fish, at the conclusion of the upstream mi- 

 gration, are concentrated in a holding area, 

 such as a lake, and the spawning migration is 

 out of the lake into tributary streams, trapping 

 at the start of the spawning migration is pos- 

 sible . When the interval between the upstream 

 and spawning migrations is long, in excess of 

 one month; when the fish disperse at the conclu- 

 sion of the upstream migration; and when the 

 spawning migration consists of a local move- 

 ment either up or downstream; then, the fish 

 must be diverted while still concentrated on 

 their upstream migration and especially designed 

 holding ponds employed to retain the fish until 

 sexual maturity. 



The problems encountered in the reten- 

 tion of adult salmon are not new. Atkins (1884) 

 reports varying degrees of success with differ- 

 ent holding pond types used for the retention of 

 Atlantic salmon (Salmo salar). Hume (1893) at- 

 tempted to hold Pacific salmon in small ponds 

 with some success. The most extensive holding 

 attempt was conducted on the Grand Coulee Pro- 

 ject where the entire Upper Columbia River runs 



of Pacific salmon were transported and held 

 either in streams or holding ponds until sexual 

 maturity. The results of this relocation, to- 

 gether with experiments designed to determine 

 factors influencing successful retention, were 

 reported by Fish (1944). 



The holding experiments conducted by 

 Fish indicated that injury and disease, aggravated 

 by unfavorable environmental conditions, were 

 the primary causes of mortality in adult salmon. 

 Subsequent experiments have demonstrated that 

 holding pond design can be a significant factor 

 in the reduction of the holding mortality and that 

 under favorable environmental conditions the 

 effects of injury and disease may be significantly 

 reduced. 



Twenty years of experimentation and ob- 

 servation provide background for this report; 

 the men who made active contributions are too 

 numerous to mention. The Branch of Fish Hatch- 

 eries of the Bureau of Sport Fisheries and Wildlife 

 and its predecessor organizations financed the 

 building of the experimental holding ponds. Par- 

 ticular gratitude is expressed to Mr. A. V. 

 Tunison and Mr. William Hagen, Jr., of this 

 Bureau and Dr . L . Edward Perry, now with the 

 Bureau of Commercial Fisheries, for their faith 

 and support in the development and testing of the 

 experimental holding pond designs . 



Mr. Scott Bair, now of the Chelan County 

 Public Utility District No. 1, prepared the original 

 construction drawings for the Entiat and Winthrop 

 holding ponds and Prof. Harry H. Chenoweth, of 

 the University of Washington Engineering School, 

 the design drawings included in this report. 



The holding pond systems described have 

 no single prototype in operation but, rather, are a 

 composite of holding ponds and traps constructed 

 at the Entiat, Winthrop, and Carson, Washington 

 National Fish Hatcheries together with altera- 

 tions designed to improve operation. The 

 recommended plan for the use of holding ponds 

 in series has not been tested in actual operation. 

 In the presentation, the holding ponds and trap- 

 ping systems are described separately because of 

 the different problems involved. 



