Spawning populations in Zone 2 (above Ocqueoc Falls) were 

 sli^tly reduced from those present in 19U7. I attribute this 

 to lower -water levels in 19li8 ivhich rendered the Ocqueoc Falls 

 impassable to the sea lampreys at an earlier date. Ho-vvever, an 

 increase, disproportionate to the decline noted above., was ob- 

 served in spawning activity below the falls. Nesting sites 

 below the falls became so overcromied that after June 8, when 

 l,ii83 nests were coionted between Stations IL and 111, further 

 counts of the nests in this area could no longer be made accur- 

 ately. Other areas in the zone displayed an appreciable increase 

 in spawning activity over the 19U7 season. 



In the various areas in Zone 1 (from the estuary to Ocqueoc 

 Falls), the amount of sea lamprey spawning activity in a given 

 area ■was directly proportional to the amount of gravel, in riffle 

 areas or otherwise, that was present. As will be subsequently 

 demonstrated, gravel or gravel and small rubble are essential 

 for sea lamprey nest construction and without these particular 

 elements (or seme suitable substitute) nest construction and 

 spawning do not take place. Between Stations IL and Hi, imme- 

 diately below the falls, the stream is characterized by short 

 graveled riffles alternating with deep pools. Bottom types in 

 general are gravels of assorted sizes except the deeper pools 

 ■which are silted or sandy. The heaviest spaivning concentration 

 in the zone (and in the river, for that matter) occurred in this 

 0.5-mile area. Act^ually, 78.1 percent of the spa^wning activity 

 in Zone 1 occurred here. (Table 5, Figure 28, and Appendix G, 

 Table 1.) 



Do-mnstream from this area gravel bottom types disappear 

 rapidly, giving way to sand, and sea lamprey spa^wning acti^vity 

 decreased accordingly. Between Stations IF to IJ (1.9 miles) 

 the bottom type ■was almost exclusively sand and the 12 sea • 

 lamprey nests found there in 19li7 were limited to about ei^t 

 small patches of gravel primarily located at, or near, old stream 

 improvement devices. A recurrence of scattered gravel riffles 

 and isolated gravel bars in the lo'wer reaches of the zone abo'sre 

 Ocqueoc Lake (Stations IC-IE) was accompanied by a complete 

 utilization of -these areas by spawning sea lampreys. 



Seventy percent of ■the spa^wning below Ocqueoc Lake (S^bations 

 lA-lB) took place in a 900-foot area immediately beloTv the cutlet 

 of the lake. This area is characterized by riffles with bottom 

 types of gravel, mussel shells, and sand. The balance of the 

 spaivning between this area and the estuary took place on the 

 patches of gravel ■which infrequently replaced the generally sandy 

 bottom. 



Spawning in the tributary. Silver Creek, was limited to 

 small patches of gravel at, and between. Stations l^B and hC 

 These gravelly spots were located at high-way crossings and 7?ere 

 the result of erosion of the road grade. Spa^wning in the Little 

 Ocqueoc River was limited to a 200-yard area of gravel riffles 



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