(Figure 28) (below Ocqueoc Lalce) completed their spasming in 

 approximately 16, 19, and 20 hoiirs respectively as determined 

 by placing hardware cloth fences around the nests. 



The location of the eggs deposited in the nest and those 

 lodging in surrour.ding areas was deten-zined by carefully dis- 

 secting, stone by stone, a series of ten nests in -lAdiich spaivn-- 

 ing h^d been completed. Dislodged eggs were caught in a strean- 

 bottom sampler and the relative proportions in different layers 

 and different areas of the nests were estimated therefrom. 



The distribution of tlie eggs found in these nests was 

 logical considering the spaiwiing position, spawning act, and the 

 action of the "ivater current passing through and over the nest. 

 In all nests examined, the b'olic of the developing eggs was found 

 in a spindle-shaped layer (in both vertical and horizontal dimen- 

 sions) in the upstream face of the crescentic, doimstream margin 

 of the nest. Here they were mixed Tdth fine and coarse sand 

 ■which filled the interstices among the pieces of gravel and stone. 

 Superimposed upon this egg-bearing stratum was a 2- to 5-inch 

 layer cf medium and coarse gravel among which few eggs or sand 

 grains "vvere present. The water percola.ted freely through this 

 layer. It was found that among the eggs first deposited by a 

 spawning pair, some were buried as deep as 8.5 inches beneath the 

 highest point of the nest rim. The egg-bearing stratum itself, 

 varied from 2 to U inches at its maximum thickness (Figure 32a, b), 

 In the lateral plane, the eggs were most commonly distribij^ted 

 over an area equivalent in breadth to the downstream quadrant of 

 the nest (Figure 32c). 



In an area of moderate current, with a generally gravel 

 bottom type, a few eggs were found lodged in the gravel just 

 past the crescentic rim of the nest. Occasional eggs were lodged 

 among the gravel of the stream bed directly behind the nest fcr 

 a distance of three to four feet (Figure 32a). In generally 

 sandy areas, where the reverse slope of the nest rim (downstream 

 side) was predominantly sand, eggs carried over the rim of the 

 nest by the current had nowhere to lodge and I observed that 

 these eggs generally were carried by the current into deeper and 

 usually silted areas (Figure 32b). I believe that there is a 

 high mortality among these eggs due to their being exposed to 

 predation by small fishes and other organisms and, ultimately, 

 to their being sm.othered by silt deposition. 



(3) Nest construction 



The manner and form of sea lamprey ne^t construction ii^. the 

 OcqueoG River varied with the area in tlie watershed selected for 

 spa^-ming, with the bottom types that were present, and with spe- 

 cific locations ■prithin the stream (i.e., particular nest-build.ing 

 site selected). 



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