Manchester Memoirs, Vo/. Ivii. (191 3), Xo. 3. 



III. The Scientific Results of the Salmon Scale 

 Research at Manchester University. 



By Philippa C Esdaile, M.Sc, 



Research Fellow 211 Zoology, Universily of Manchester. 



(Commiuiirnted by Professor S. J. Hicksoii, D.Sc., F.R.S.) 



( Received and react December loth, igi2.) 



The study of the fresh-water fauna is at all times 

 most interesting-, but the abnormal drought experienced 

 in this country during the summer of the year 191 1 

 greatly increases the interest as well as emphasises the 

 difficulties which are always to be met with when carrying 

 on such work even under normal conditions. 



The salmon, living a double life, changing first from 

 fresh to salt v/ater and then back again to the river, cannot 

 but have been influenced by the extraordinary absence of 

 rain, which reduced the rivers to foul and meagre streams, 

 tending to breed disease instead of providing a ready 

 means of access to suitable spawning-beds. Therefore in 

 all studies relating to salmon any abnormal weather con- 

 ditions must be taken into consideration, and the records 

 obtained during such an abnormal year must not be com- 

 pared with those of a normal year, unless the differing 

 conditions are kept well in mind. The results obtained 

 from the study of salmon under such unusual weather 

 conditions as were experienced in 191 1 may very possibly 

 be most important. Frequently during scientific investi- 

 gations valuable knowledge can be gained by subjecting 

 the creatures under consideration to different conditions 

 of life, such as placing fish on various kinds of back- 



Februaiy 6tli, igij- 



