THE SMALL GAME OE THE SEA 191 



seas. Li tho central — and coldest — portions of this area are 

 animals which for the most part are found also all round the 

 coasts ; but numbers of coastal forms — and especially* the 

 shallow-water forms — do not inhabit the central banks at all '. 



On the western edge of the Shetland Banks the Michael Sars 

 found a temperature of over 48° F. at a depth of 164 fathoms. 

 This is a good deal warmer than the southern North Sea in 

 winter, and the high temperature is probably due to the Gulf 

 Stream. Here, in deep water, British investigators had located 

 certain ' southern ' animals from the Mediterranean and the 

 Atlantic as early as 1868. Some of these animals find their way 

 along the east coast of Scotland and England, but do not spread 

 eastwards. These ' southern ' forms, although they occur, do not, 

 of course, preponderate off Shetland. Most of the animals here 

 are, in fact, ' northern ' forms identical with those found among 

 the islands off the west coast of Norway. 



On the Faeroe Bank in 1902, at 54 to 164 fathoms, the MicJiael 

 Sars found the whole bottom covered with white mussel-shells, 

 with a few living specimens among them. Here in the middle 

 of August the temperature was as high as 48-8° F. Mussels 

 are, of course, normally shallow-water animals, and the Faeroe 

 temperature was very nearly the same as that on the Norwegian 

 shallows (where these mussels principally flourish) in August. 



It is impossible to pursue this most fascinating line of inquiry 

 further here. But when it is remembered that these bottom 

 animals are (many of them) fixed to the bottom, and. that very 

 few of them can wander far down a current except when they 

 are in their earliest stages of development ; when, moreover, 

 we see, as we have done, that the larvae of some of them in the 

 free-swimming stages form the food of the baby fishes during 

 the most critical period of their existence, the ' importance ' of 

 a knowledge of their life-history becomes at once evident. 



Even this very condensed summary will be enough to suggest 

 to any trawlerman that fishes are distributed very much as is 

 the ' small game ', and to suggest reasons for certain puzzles 

 like the appearance of hake in the North Sea. As Hjort puts 

 it : ' Helland-Hansen has shown that in the deeper layers there 

 is a circular current of Atlantic water in the North Sea, a branch 

 of the Gulf Stream following the east coast of Scotland, turning 

 north-east just before reaching the edge of the Norwegian 

 depression.' The latter is, in parenthesis, the deep narrow 

 trench more than 110 fathoms below the surface which runs 

 parallel to the south-west Norwegian coast from the latitude 

 of Stat to the Skagerrak. ' As a result the periphery of the 

 central portion of the North Sea is bathed by water of much the 



