CHRISTIANIA, 1901. 405 



As the most hnportant means of carryiiuj out these investigations, 

 fishing experiments of different kinds are to he imdertaken in order to 

 elucidate the distriljution of food-fishes in the varioiis 2^ci'>'ts of the sea. 

 In this conneetion attention should he cspeciallg directed to the determina- 

 tion of the depths (ivhether on the hottom or in the intermediate layers of 

 xvater) at which particidar species of food-fishes can he caught. 



It is much to he desired that lahelled (or marked) fishes of important 

 species {e.g. p)laice, salmon, etc.) shoidd he liherated in as large numhers as 

 possihle and over loide areas. 



Special researches should also he directed to determine the extent to 

 which important food-fishes are destroyed hy their natural enemies. 



§ 4. In connection with the fishing experiments it is desirahle that 

 investigations shoidd he made to determine the extent to uhich the vitcdity 

 of the fishes caught with the trawl and other fishing implements is 

 affected therchy, and whtthcr such fishes are, or are not, in a condition to 

 live after liberation. 



III. 



§ 5. Determination of the quantitative distribution of the eggs, pela- 

 gic larva3, and young fishes of the species mentioned in 11. § 2, during 

 the periodic cruises proposed in the hydrographic programme and at the 

 stations fixed for those cruises. 



The investigations are to be carried out, firstly, by vertical hauls with 

 Hensen's large egg-net, and secondly, with larger horizontal nets adapted 

 thereto. 



§ 6. It is further desired that the eggs and larvcv of the above-mentioned 

 food-fishes shoidd cdso be collected and accurately studied in the intervcds 

 between the hydrographic cruises, and especially during the spawning 

 periods of these fishes. 



§ 7. Experiments are further desired upon the artificial fertilisation 

 and hatching of the eggs of the most important of the food-fishes men- 

 tioned, not only on the steamers for scientific ivork, hut also on hoard 

 commercial fishing -vessels and on shore. 



IV. 



§ 8. Investigations upon the local varieties of plaice, herring, and 

 mackerel in the entire international area of research are to be assisted 

 by the collection of suitable material in all countries, to be placed at 

 the disposal of individual specialists for detailed investigation, through 

 the agency of the Central Bureau. 



§ 9. It is desirahle that such investigations should he extended also to 

 other useful species of animcds. 



