FISHERIES, GAME AND FORESTS. 215 



deserted. This has been left as a mystery in publications on the subject, but we are 

 well convinced that it is because the lampreys do not find the requisites or proper 

 conditions of bottom (rocks, sand, etc., as given below) to supply all their needs and 

 fulfill all conditions for ideal sites. In the illustration of the spawning sites of the 

 Lake Lamprey (see illustration No. 10) the stakes without papers were placed in nests 

 that were never completed or used. This desertion of half-constructed nests is just 

 what would be expected and anticipated in connection with the explanation of 

 " Requisite Conditions for Spawning," given below, because some shallows contain more 

 sand and fewer stones, and others contain many larger stones but no sand, while others 

 contain pebbles lying over either rocks or sand. The lampreys remove some of the 

 material and if they do not find all the essentials for a spawning nest, the site is 

 deserted and the creatures move on. 



Requisite Conditions for Spawning. 



For a spawning site two conditions are immediately essential — proper conditions 

 of water and suitable stream bed or bottom. Of course with these it is essential that 

 no impassable barriers (dam or falls) exist between the lake and the spawning sites to 

 prevent migration at the proper " running " season. They will not spawn where there 

 is no sand lying on the bottom between the rocks, as sand is essential in covering the 

 eggs (see remarks on the " Spawning Process ") ; neither will they spawn where the 

 bottom is all sand and small gravel, as they cannot take hold of this material with their 

 mouths to construct nests or hold themselves in the current, and they would not find 

 here pebbles and stones to carry over the nest while spawning, as described elsewhere. 

 It can thus be seen that, as suggested above, the reason they do not spawn in Fall 

 Creek and Cascadilla Creek, between the lake and the falls, is that the beds of these 

 streams are very rocky, being covered only with large stones and no sand. There 

 is no doubt that the lampreys find here suitable conditions of water, but they do not 

 remain to spawn, on account of the absence of the proper conditions of stream bed. 

 Again, they do not spawn in the lower course of the inlet for a distance of nearly two 

 miles from the lake, because near the lake the bed of the stream is composed of silt, 

 while for some distance above this (up stream) there is nothing but sand. Farther 

 up stream are found pebbles and stones commingled with sand, which combination 

 satisfies the demands of the lampreys for material in constructing nests and covering 

 eggs. The accessibility of these sites, together with their suitable conditions, render 

 the inlet the great and perhaps the only spawning stream of the lake ; and, doubtless, 

 all the mature lampreys come here to spawn, excepting a few which spawn in the 

 lower part of Six-mile Creek, a tributary of the inlet. 



