142 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



The plankton taken in Lake St. Clair has uot yet been counted, owing to delay in 

 procuring apparatus, but it is hoped this will be accomplished during the year. 



The fish culturist and the fisherman will now wish to know what practical results 

 have come from our work. The work was undertaken as a scientific problem, the 

 determination of the biological conditions existing in the lake. This problem is very 

 large and will necessarily, more especially if extended to the whole chain of lakes, 

 involve the work of many investigators for many years. It is believed that the past 

 summer's work is a step toward its solution. Any operation of practical fish-culture 

 which involves Lake St. Clair is likely to be guided to some extent at least by the 

 data which we have collected. 



It must deal with a shallow, roily lake, poor in plankton and in littoral forms, 

 but rich in bottom fauna and flora. Bottom-feeding fish which are adapted to roily 

 water of this temperature will find here a rich pasturage. This is illustrated in the 

 case of the carp, which seems to have made its way into the lake through the small 

 tributary streams. This fish is multiplying rapidly and is of excellent quality. 



It was hoped that we should find in the lake the young whitefish and that we 

 might be able to determine the conditions under which this fish lives. In this we were 

 disappointed. It is possible that a search begun earlier in the season and with more 

 elaborate apparatus would succeed. It is manifestly not possible to say whether or not 

 the lake is a suitable one in which to plant whitefish, until we know the habits of the 

 fry. If the fry feed only upon the minute Crustacea of the surface plankton, as Forbes 

 found them to do in confinement, then they would find food much more abundant in 

 the region of the Put in Bay Islands in Lake Erie than in Lake St. Clair. If they feed 

 upon the many small animals which inhabit the bottom vegetation (this is the habit of 

 the adult whitefish) then it would be hard to find a better place than Lake St. Clair. 



The Michigan Fish Commission has made a beginning in the investigation of the 

 biology of the Great Lakes. It has shown great foresight in instituting the work, has 

 provided liberally for it, and has not hampered it by unwise restrictions. Such an 

 investigation, carried out as a scientific enterprise, without restriction, is sure to yield 

 results of the utmost value to the fisheries. This statement needs no other justifica- 

 tion than is contained in the facts alluded to at the beginning of this paper, the fact 

 that both the fish-culturist and the fisherman are dealing with a problem with but little 

 knowledge of the nature of the materials involved. Let them study to understand 

 the nature of these materials. Let us have a biology of the Great Lakes and we shall 

 have both fish-culture and fishing on a surer basis. 



To build up a knowledge of the biology of the Great Lakes must take the time of 

 many men for many years, and must require the expenditure of large sums of money. 

 It is an enterprise that should commend itself to every State which has an interest 

 in fish-culture in the lakes. Especially should such an enterprise commend itself to 

 the commercial fisherman, as he has much to gain by it. 



