Biological Survey — Erie-Niagara Watershed 17 



facilitate acquaintance with the species of local interest or serve 

 to give emphasis to problems of basic importance in the fishery. 



The colored plate of the cisco, or common lake herring (Plate 

 Xo. 1) is an aid in the difficult task of identification of other 

 closely allied members of the herring- group whose decline during 

 the past few years has occasioned concern in the commercial fishery. 

 The whitefish (Plate No. 2) choice commercial fish of the lake, has 

 declined to an inconspicuous place in the fishery. A vast array 

 of facts must be sought bearing on the interrelations of the lake 

 population before progress can be made constructively in rehabili- 

 tating this fishery. 



The gold carp (Plate No. 3) is an alien in these waters, having 

 been introduced from Europe. It is of questionable value econom- 

 ically. It multiplies with great rapidity in the shallows, usurping 

 space of less prolific but more important species in the economy of 

 the lake. It requires serious study. The fat-head (Plate No. 4) is a 

 minnow with fish cultural possibilities because of its non-competi- 

 tive food habits and its great prolificity in reservoirs and ponds 

 where reproduction continues throughout the summer season. 



The stonecat (Plate No. 5) is a troublesome member because of 

 its poisonous spines. For this reason it is not marketed though 

 its flesh is excellent. 



The perches, illustrated in Plates Nos. 6-8, make a notable contri- 

 bution to the fishery of Lake Erie. The sauger and yellow pike, 

 often called wall-eye or pike-perch, of the more shallow waters in 

 the lake, are of interest chiefly to the angler while the blue pike, a 

 deep water species of this group, affords large catches to the com- 

 mercial fishermen. 



The annotated list* summarizes important data of each of the 

 species illustrated as well as others which have been found in the 

 drainage area. 



Results of the Survey. — Proper survey technique combines 

 two steps, — the acquisition and analysis of the facts and their use 

 in the development of a program of intelligent action. Many 

 so-called practical studies have not led anywhere because they 

 lacked a scientific basis. It is true also that many scientific inves- 

 tigations have not led to anything practical. It is the object of the 

 survey to relate more closely scientific study to our practical 

 problems. 



The question may well be asked, — how is the biological survey 

 working out in practice? With our stint of "a watershed a year," 

 it is manifestly impossible to cover all problems thoroughly in 

 a single season even with a large force in the field, — hence, the 

 importance of follow-up studies. However, we are accomplishing 

 our main objectives by putting into operation as we proceed with 

 the surveys a more intelligent stocking policy. We are accumulat- 

 ing valuable "by-products" in the way of useful data such as 

 information of the underlying factors of productivity of the fish- 



* See page 106. 



