Biological Survey — Oswego Watershed 165 



Very closely related brook lampreys are present on the west coast 

 of America, and in the streams of Europe, Siberia and Japan 

 (Regan 6 ). 



In size, the brook lampreys are the smallest of all the lampreys. 

 Those of New York State are on the average only slightly longer 

 when they transform than the transforming sea and lake lamprey, 

 but unlike them, the brook lamprey never increases in size after 

 transformation (Fig. 7). 



Nest=BuiIding and Egg=Laying. — These activities are so similar 

 in all the different lampreys that a description of one is practi- 

 cally a description of all. 



No matter whether the lampreys live in the ocean, the lakes or 

 the brooks during their adult life, they all go up the fresh-water 

 streams to lay their eggs. The time in this State is from April 

 to the first of July. The brook lampreys are the earliest. In the 

 western part of the State the egg-laying some years may begin 

 the last of March and continue into April, while in New York 

 City it may begin as early as the middle of April. In Ithaca 

 the season is from the first to the 20th of May, but in different 

 years may be somewhat earlier or later following the temperature 

 (Fig. 3). 



Occasionally the spawning period of the brook lamprey may 

 continue until the first lake lampreys appear, but the overlapping 

 is quite infrequent and happens only in years when the season is 

 unusual. 



The spawning time of the lake and the sea lampreys commences 

 most often during the latter part of May, reaches its height in 

 June and may extend into July. They do not all go up at the 

 same time. It has been frequently noticed that after a warm rain 

 many new pairs of lampreys ascend the streams; also that in the 

 same or neighboring nests there may be completely spent females 

 and those full of eggs. 



Brook lampreys may lay their eggs in water as cold as 10° to 12° 

 Cent. (50° to 54° Fahr.) but more often the water is from 

 15° to 18° Cent. (59° to 64° Fahr.). With the lake and the sea 

 lampreys the water at the spawning time is usually from 15° to 

 21° Cent. (59° to 70° Fahr.). 



Nest-building : In raising a family the first thing needed is a 

 home and the home-maker is very often and ought always to be 

 the male. All the lampreys follow the good rule, and the male 

 goes ahead and starts things, but the female is no sluggard and 

 when she comes along she joins vigorously in the nest-building. 

 This nest or home is built in running water, most often a short 

 distance above rapids or riffles, as the fishermen call them. It is 

 a wash-bowl shaped excavation in the bottom of the stream made 

 by pulling the stones away from an area selected and depositing 

 them around the edge, especially the lower edge. To remove the 



6 Regan, Gr. C. Tate. A synopsis of the Marsipobranchs of the Order of Hy- 

 peroartii. Annals and Magazine of Natural History, ser vii, Feb. 1911. 



