226 Fishes of 1907 Cruise 



We are indebted to Mr. Opie, who acted as naturalist during the 

 first section of the cruise, for very careful notes on the specimens 

 which came under his observation. During the rest of the cruise the 

 material was dealt with by Captain Buchan Henry. 



So far as the fishes are concerned, the main interest lies in the 

 additional evidence afforded of the difference between the fauna of 

 the comparatively cold-water area lying to the north and east of the 

 Wyville-Thomson ridge and that of the warmer water which extends 

 southwards and westwards from that ridge. 



The absence of any hauls from the immediate neighbourhood of 

 the actual ridge makes it impossible to say whether the species of fish 

 ordinarily found on either side of it are ever to be found in company 

 in its immediate neighbourhood, or whether the comparatively sudden 

 change of temperature forms a barrier which is not passed by fishes 

 which elsewhere have a range including both extremes. Among the 

 species taken by the Silver Belle, Sebastes marinus alone among 

 bottom-living forms was captured on both sides of the ridge, in 

 positive temperatures of 9*6° C. and l - 8° C. It is perhaps worthy of 

 remark that, while in the neighbourhood now under consideration 

 Cottunculus Tkomsoni is found only in the warmer regions, in tem- 

 peratures of about 7° to 8° C, and C. microps only in the colder 

 region, in temperatures of about 0° to -2° C, yet both species have 

 been taken between Iceland and Greenland in temperatures of about 

 3-5° C. (Liitken, 1898) and between 3-9° C. and 7-7° C. in the Western 

 Atlantic by the Albatross. 



The main interest, so far as the fishes are concerned, lies in the 

 fact that some hauls were made in the cold-water area lying to the 

 north and east of the Wyville-Thomson ridge, and others in the warm- 

 water area to the south and west of that ridge. The extraordinary 

 difference of the fish fauna of these two adjacent areas shows 

 most clearly the great influence of temperature — or, perhaps, more 

 accurately speaking, of a sudden change of temperature — upon the 

 distribution of even such active animals as fishes. 



Of the fifteen species of fish taken by the Silver Belle in the warm 



