intertidal areas and (2) estimate the total num- 

 ber of fry produced in streams entering the 

 Sound. 



2. The experimental design for estimating 

 production of fry was one of stratified random 

 sampling with proportional allocation of the 

 sample. Streams were stratified by size and 

 timing of adult spawning migrations. Eight 

 streams were included in the sample. Different 

 techniques were used to estimate the produc- 

 tion of fry in the stream proper and in the 

 intertidal areas. 



3. Pink and chum salmon fry migrating 

 downstream from areas above tidal influence 

 were sampled by means of metal traps. Traps 

 were fished 24 hours each day throughout the 

 migration (April, May, and June), except when 

 they were removed for cleaning or were being 

 relocated. 



4. The proportion of seaward-migrating fry 

 captured by the traps in each stream was es- 

 timated by measuring the proportion of water- 

 flow strained by the traps and by means of 

 marking and recovery experiments. 



5. The contribution of intertidal areas was 

 estimated by a system of quadrat sampling 

 of pre-emergent fry in the gravel. 



6. The results of intertidal sampling were 

 combined with upstream trapping data to pro- 

 vide an estimate of the total fry production 

 for the study streams. The averages for the 

 various study streams were inflated to give es- 

 timates for each group or stratum of streams. 



7. Totals of 211,116 pink salmon fry and 

 54,418 chum salmon fry were taken in traps 

 from eight streams during this study. The 

 estimated total numbers of pink and chum 

 salmon fry produced in four strata, which 

 include the majority of streams in the Sound, 

 were 103,000,000 and 14,500,000 respectively. 



8. In addition to providing estimates of the 

 production of fry from the majority of Prince 

 William Sound streams, the 1957 studies pro- 

 vided information needed for improving the 

 efficiency of sampling. The timing and dura- 

 tion of the migrations of chum and pink salmon 

 fry were determined. The migration patterns 

 for the two species were usually similar in 

 each stream, but pink salmon fry emerged 

 much earlier at one study stream, and chum 

 salmon fry emerged first in another stream. 

 The excavations of many quadrat samples re- 

 vealed that intertidal spawning was much more 

 extensive than was realized prior to beginning 

 the studies. 



9. The authors concluded that more efficient 

 means of sampling were required than was 

 afforded by traps. The operation of fixed traps 

 was expensive and inadequate, since a large 

 proportion of the fry are produced in the 

 intertidal areas below the traps. Recommenda- 

 tions for the design of future salmon fry 

 sampling programs include: (1) Determine the 

 extent of adult spawning activity in each study 

 stream, (2) develop more practical means of 

 extracting eggs and larvae from the gravel, 

 and (3) consider the variability of fry distribu- 

 tion in establishing the amount of sampling 

 needed. 



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