MOVEMENTS OF HERRING AND OTHER MARINE FISHES. 333 



ring, and the presence in valuable numbers of many other fishes. 

 Their tendency to avoid acid waters, hydrogen sulfide, etc., 

 which result from decomposition and are increased by the pres- 

 ence of refuse of fish canneries, sewage, etc., makes diversion of 

 such refuse from the sea an important consideration.. The 

 Baltic towns of the Hanseatic League were dependent in part 

 upon the herring industry and after a century of great growth 

 and prosperity fell into decline at the middle of the fourteenth 

 century. Their prosperity was the accompaniment of the pres- 

 ence of great shoals of herring off the Island of Riigen in the 

 Baltic. Their decline was caused in part by the failure of the 

 herring industry and the supposed migration of the herring to 

 the North Sea which has since been the center of the industry. 

 Schouwen (on the Netherland coast of the North sea) appears 

 in the fourteenth century to have been frequented by the her- 

 ring shoals in preference to Riigen (Yeats, '86). The rapid 

 growth of the Netherland cities, their supremacy and final sepa- 

 ration from the Hanseatic league followed. A little later the 

 herring again changed their haunts choosing the coast of Norway 

 where both Norsemen and Netherlanders caught them. The 

 Beukelszoon method of curing herring having come into use 

 nearness to home was no longer a necessity. The Norse fisheries 

 flourished until 1587 when an *' apparation of a gigantic herring 

 frightened the shoals away." Thus it appears that the develop- 

 ment of the herring industry in each locality led to the apparent 

 desertion of the locality by the fish, though the migrations 

 assumed by historians may be doubted (Yeats) (Putzger '01, 

 p. 17a). Was this due to the contamination of the sea by 

 the cities, or merely to over catch? Whichever may have been 

 the case it is certain that contamination will not invite runs of 

 the herring. The common assumption that the sea is so large 

 that pollution cannot have a significant r61e is rendered entirely 

 untenable by the greatly increased sensitiveness of the marine 

 fishes as compared with fresh water ones. 



VI. Acknowledgments and Bibliography. 



One hundred and twenty-five dollars of the expense of this 

 research was borne by the University of Chicago, the remainder 

 by the Puget Sound Marine Station. 



