Kindle — Note on Bottom Currents in Lake Ontario. 195 



fishermen who set their nets in water 150 to 250 feet deep on 

 the fishing grounds sixteen to twenty miles south of Presque 

 Isle, that their floats are at times pulled down below the surface 

 by the bottom currents so that they are sometimes unable to 

 locate and haul up their nets for several days. They endeavour 

 to avoid setting nets on sand bottom, stating that the currents 

 when running are apt to make rope-like masses of them 

 when set on sandy bottom. Hard or rocky bottom is chosen 

 for setting nets for this reason. The deep water nets are 

 anchored near the bottom by weights of from 75 to 100 pounds. 

 The nets carry in addition about \ lb. of lead for each 10' of 

 net. Notwithstanding these heavy anchors and distributed lead 

 weights it is said that nets are sometimes moved some distance 

 by bottom currents during heavy storms. In such cases the 

 nets, which are generally several hundred feet in length, are apt 

 to be pulled into a horseshoe shape, the end anchors being 

 found near together. It is evident that currents which would 

 greatly disturb and sometimes ruin fishing nets or cause them 

 to drag heavy anchors would be very effective distributors of 

 fine and possibly of rather coarse sediments. 



It is not alone as carriers of rock-making materials, however, 

 that these bottom currents possess interest and invite investiga- 

 tion. They are important factors in the ecology of lake life. 

 In those areas where they appear with most regularity and 

 vigor they will doubtless be found to greatly stimulate the 

 abundance of molluscan and vegetable life as well as the fish 

 life which feeds upon it. It is not improbable that the areas 

 which deep water fishermen have found to furnish the best 

 fishing ground will be found to lie in zones where strong bot- 

 tom currents are more prevalent than elsewhere. The writer 

 found, while examining the bottom of Lake Ontario at the head 

 of the St. Lawrence with the aid of a diving suit, that the strong 

 bottom outflow current into the St. Lawrence exercises a very 

 marked influence over the distribution of the Unios and other 

 large bivalves. These large shells could be readily seen through 

 the windows of the diving helmet in twenty-five or thirty feet 

 of water. In descending from the shallow inshore water on 

 the east shore of Wolf Island opposite Cape Yincent into the 

 channel, one passes from an imperceptible current into the 

 strong steady bottom outflow current of the head of the St. 

 Lawrence. On the still- water zone shell fish are very scarce 

 but on the current-swept bottom they are abundant, ten or 

 twelve large bivalves being sometimes observed in the space of 

 one square foot. Although familiar with a large part of the 

 shores of Lake Ontario and Lake Erie, the writer has nowhere 

 else seen the large fresh water molluscs in numbers which 



