Examination of streams on Grand Island 



Of 23 streams on the island, 21 cannot be utilized \sy sea 

 lampreys because of one or more of the following limiting factors: 

 small size, low temperatures, and the presence of bedrock barriers 

 ranging from & to 100 feet in height. 



North Light Creek (at the northern end of the island), a 

 stream approximately 3 miles in length, flows from a tag alder swamp 

 and is soft bottomed throughout; this stream is unsuitable for spawn- 

 ing lampreys due to a lack of spawning gravel. 



Echo Lake Creek (T U7 N, R 19 W, S U, on the western side 

 of the island), the outlet of Echo Lake, is approximately 1/2 mile in 

 length, 10 to l5 feet in width, and up to 10 inches in depth. Water 

 temperature on June 21 was 60° F. Spavming raediara for 2$ or more 

 nests is present. Sea lampreys can be blocked from this stream by a 

 25-foot wide concrete barrier placed at the mouth. Power lines are 

 present only at the south end of the island, a distance of at least 

 3 miles. The stream can be reached by automobile. The proposed weir 

 site is approximately 300 feet from the road. 



Examination of streams in Wisconsin 



Iron County t Contains 8 small streams (Fig. 2), U of which can pro- 

 bably be utilized by sea lampreys (Table 1). The productive poten- 

 tials of the latter range fi-ora small to medium (Loeb and Hall, 19$2)» 

 Electrical control devices are recommended. 



All of the streams are subject to rapid fluctuations in 

 water levels and several to a resulting heavy turbidity. Bottcan irre- 

 gularity and scouring by sudden freshets may limit the extent of 

 utilization by sea lampreys even in the streams considered to have a 

 productive potential. 



Installation and operation of control devices will be hin- 

 dered by the relative inaccessibility of two streams, and l^ occasional 

 excessive turbidity (lake clay). 



Ashland County ; Contains 11 watersheds (Fig. 3), 5 of which have pro- 

 dactive potentials ranging from small to large (Table 2), 



The condition of Denomie Creek could not be determined be- 

 cause of continual heavy turbidity, and the Kakagon River and Wood 

 Creek Slou^ irere incompletely examined for the same reason. Heavy 

 and continual turbidity also prevented the sxirvey of the main portion 

 of the Bad River except in the portion between the mouth and U. S. 

 Highway 2j spawning habitat was found in three tributaries, however, 

 during a brief period when they were clear. 



