APPENDIX E: HEINCKE — 4 — 



history of the food-fishes by special exact observations. It has been obliged in the main, 

 to restrict its attention to the region specially assigned for the German investigations, i. e. 

 the eastern and south-eastern part of the North Sea, and the western and southern part of 

 the Baltic, but chief attention naturally was devoted to the North Sea. With regard to 

 the south-eastern portion of this sea — the true German Bight — we had already col- 

 lected, long before the beginning of the international investigations, a large number of 

 observations regarding the natural history of the food-fishes, which could now be utilised 

 and their correctness tested by fresh investigation. 



The following have taken part in carrying out the investigations — both at sea as 

 well as at the laboratory of the Station — the director Dr. H ein eke, the subdirector 

 Dr. Ehrenbaum, the scientific, assistants Dr. Strodtmann, Dr. Bol au, Dr. Maier and 

 Dr. Immermann. Ehrenbaum and Strodtmann have investigated the eggs and 

 larvae of the food-fishes; Heincke their youngest, fully-formed stages; Heincke, Maier 

 and Immermann the determination of the age and maturity; the last-mentioned and 

 Bolau the distribution of the older fishes; Bolau their food and their migrations as 

 determined by the setting-out and recapture of marked fish. The following account of the 

 most important results attained through the investigations of the Biological Station, is 

 accordingly to be looked upon , as a comprehensive common report of all the workers 

 mentioned. 



As already mentioned in the beginning, the observations on the natural history of the 

 fishes are to form the basis for an exact knowledge in the future of the habits and con- 

 ditions of life of the food-fishes, for a rational comprehension of the productivity of the sea 

 as regards food-fishes, for an answer to the questions whether overfishing is taking place 

 in the North Sea, if protective legislation is possible with any chance of success, and for 

 many others. One may also add, that these observations are the only possible 

 basis for many of these questions, for all but one absolutely indispensable. 



Several very serious demands are therefore made on the investigation of this region. 



The first of these demands is, that very many observations must be 

 made, in order to gain the broadest basis for our future knowledge. Above all, it is 

 necessary to obtain many continuous series of similar observations. We. must take 

 whole series of tow-nettings for eggs, for example, during the months-long spawning- 

 period of a food-fish, such as the plaice or cod, at short regular intervals and simul- 

 taneously if possible, at several places of the often widely - extended spawning region. 

 Again, in order to determine exactly the occurrence of young plaice of the first and second 

 year, we must fish for these at one and the same suitable spot with suitable apparatus 

 throughout the entire year, if possible at weekly and not less than monthly intervals. To 

 take a third example, in order to comprehend the migrations of the plaice within a fixed 

 region throughout the year, e. g. in the German Bight, we must mark and set out not 

 merely several hundreds but several thousands of plaice. Lastly, such series of observations, 

 when once successful, must be continued for a certain minimum number of years, in the 

 same manner as is done in other scientific fields with all series of observations, if the 

 general rule, free from chance fluctuations, is to be learnt. 



