GENERAL BIOLOGY 707 



' Navarino' sailed for about 150 miles through waters dotted Destructive 

 as far as the eye could reach with dying fishes. Computations rfiigl of^'''^'' 

 made by Captain J. W. Collins seem to indicate that an area temperature. 

 of from 5000 to 7500 square statute miles was so thickly 

 covered with dead or dying fish that their numbers must have 

 exceeded the enormous number of one billion. Since there 

 were no signs of any disease, and no parasites found on the 

 fish brought in for examination, their death could not have been 

 brought about by either of these causes ; and many conjectures 

 were made as to the reason of this wholesale destruction of 

 deep-water fishes, such as would ordinarily be unaffected by 

 conditions prevailing at the surface, submarine volcanoes, heat, 

 cold, and poisonous gases being variously brought forward to 

 account for the loss of life. Professor Verrill has noted the 

 occurrence of a strip of water having a temperature of 48 to 

 50' Fahr., lying on the border of the Gulf Stream slope, 

 sandwiched between the Arctic current on the one hand and the 

 cold depths of the sea on the other. During 1880 and 1881 

 Professor Verrill dredged along the Gulf Stream slope, obtaining 

 in this warm belt, as he terms it, many species of invertebrates 

 characteristic of more southern localities. In 1882 the same 

 species were scarce or totally absent from places where they 

 had previously been abundant ; and this, taken in connection 

 with the occurrence of heavy northerly gales and the presence 

 of much inshore ice at the north, leaves little doubt that some 

 unusual lowering of temperature in the warm belt brought 

 immediate death to many of its inhabitants. This is the more 

 probable, as it is a well-known fact that sudden increase of cold 

 will bring many fish to the surface in a benumbed or dying 

 condition." ^ 



From the Barents Sea we know many instances of a similar 

 destruction of animals on a large scale. The case of the boreo- 

 arctic fish, the capelan [Maliotus villosns), is specially striking, 

 millions of this fish having occasionally been found drifting dead 

 at the surface. In the Barents Sea very sudden changes of 

 temperature occur, and it is natural to conclude that the death 

 of the fish is caused thereby. The greatest destruction of this 

 kind probably occurs among the young stages, eggs and larvae of 

 fishes. As we shall see later, these young stages may be removed 

 by currents very far from the places w^here they are capable of 

 developing, and in all probability they are also liable to 



1 Sir John Murray, "On the Annual Range of Temperature in the Surface Waters of the 

 Ocean," Geogr. Jouni. vol. xii. pp. 128-130; 1898. 



