METHODS OF STUDYING THE HABITS OF FISHES. WITH AN 



ACCOUNT OF THE BREEDING HABITS OF 



THE HORNED DACE. 



J* 



By JACOB REIGHARD, 

 Professor oj Zoology, University 0} Michigan. 



I. METHODS. 



The studies upon which this paper is based have been made in the field, 

 on fishes in their natural environment. Captive fish have been used only 

 when necessary to supplement field observations. As the result of this 

 work, extending over somewhat more than fifteen years, there have been devel- 

 oped certain methods which it is the purpose here to describe. These are, of 

 course, essentially field methods. The studies that produced them related to 

 the natural history of the dogfish i^Amia calva Linnseus), work begun in 1891 

 and published in 1903; the habits and development of the black bass (1903); 

 the habits of coral-reef fishes at Tortugas, Florida, published in 1909; 

 and more or less complete observations about ready for publication on 

 Lampctra wilderi, Catostomus commersoni, Catostomus nigricans, Moxostoma 

 aureolum, Campostoma anomalum, Pimephales notatus, Semotilus atromaculatus , 

 Rhinichthys atronasus, Notropis cornutus, Hybopsis kentuckiensis, and half a 

 dozen sunfishes of the family Centrarchidae. Work by the writer's students 

 on the breeding habits of local fishes (Reeves, 1907, B. G. Smith, 1908) has 

 also been utilized. 



GENERAL PRINCIPLES IN FIELD STUDY OF FISHES. 



Habituation of fish to observer. — When an observer approaches a fish for the 

 first time it nearly always happens that the fish is disturbed by the sight of him 

 or by some sound that he makes, and forthwith retreats into deep water or 

 into some nearby cover. The inexperienced observer usually considers such a 

 fish as lost to observation for good and very likely passes on in search of some 

 less wary subject. In doing this he is governed by the popular impression that 

 fish are rovers, not bound to any one locality, and that it would therefore be 

 useless for him to await the return of this particular fish to the locality in 

 which he first saw it. If it were a bird or a mammal he might at least follow 

 it in its wanderings, but with a fish this is manifestly impossible. 



In passing to a new subject for observation the inexperienced worker 

 makes a fundamental error, for, save under exceptional conditions, fish are 



B. B. K. 1908— Pt 2-28 1 1 13 



