138 



13 



are partly considered by requiring their collection from throughout the run 

 and their spawning to be at random. Only one aspect of rearing 

 practices is indirectly addressed by discussion of plans to initiate 

 volitional releases and use of passive fish graders for separating fall 

 (larger) from spring (smaller) release fish. This approach would also 

 reduce sources of unintentional artificial selection at the time of release 

 (section 3.7.4), thus increasing chances of keeping similar genetic resources 

 and life history patterns in hatchery and wild fish. Size of donor stock 

 remaining for natural reproduction is addressed by setting a healthy 

 minimum natural escapement of 1000 "wild fish", based on an estimate 

 that 1250 adults are "needed to maintain maximum wild production." 



3.3 Guidelines in IDFG Documents 



Fertilization protocol is not covered in IDFG documents reviewed, 

 although IDFG hatcheries apparently use WDF-2 (Willa Nelson, NWPPC, 

 personal communication) which contains some fertilization guidelines 

 (section 3.5.3). Discussions of donor stock source, adults mated, and 

 size of remaining donor stock are spread among IDFG-2 and two 

 subsections of IDFG-1. Relevant clauses are summarized below. 



3.3.1 Donor Stock Source (•lDFG-2') 



"Artificial supplementation will utilize indigenous stocks whenever possible." 



"Upon loss of ability to propagate indigenous stocks, the following inherent and 

 behavioral characteristics of potential donor stocks will be considered (not 

 necessarily in priority order)." 



Items (a-f) in the list after this last statement follow the approach of 

 matching the gene resources and life history patterns of hatchery 

 broodstocks to the indigenous populations with which they may genetically 

 interact. Items (g) and (h), however, contradict this approach by allowing 

 differences in migration timing or size of mature fish of donor stocks when 

 such differences would enhance a fishery. Potential impacts of these 

 differences on genetic resources and sustainability of naturally 

 reproducing stocks are not addressed. 



3.3.2 Adults Mated flDFG-n 



This factor is not clearly addressed. One statement in the harvest 

 management section of IDFG-1 (page 48) is partly relevant: 



