/\t the ninth meeting ot the International Council for the Investigation of the Sea, 

 held at Copenhagen in the month of September 1910, Dr. Hugh Smith, Deputy Commis- 

 sioner of Fisheries, U. S. A., discussed the great decline of the mackerel fishery in the United 

 States during the last 25 years, the total catch having decreased from about 500 OOO barrels in 

 1885 — 6 to 3000 barrels in 191O. The assistance of the Government, he said, had been 

 called in to investigate the matter and much information had been collected; but it had 

 become quite clear, that some new methods had to be adopted, in order to settle the 

 questions, whether the mackerel had moved on to other grounds, having perhaps migrated 

 over to Western Europe, or the purse-seine had been the cause of the decline, or whether 

 physical conditions, acting on the eggs and young, were responsible for the diminution, 

 as possibly in the case of the tilefish. To obtain information on this great puzzle, it 

 would be a great gain, if the International Council could take up the investigations on 

 the mackerel. 



The Council was very willing to meet the proposals of Dr. Smith and find a way of 

 cooperation with the U. S. Fisheries Bureau; but in order to prepare the basis of such 

 cooperation, whilst the United States were considering the possibility of joining the internatio- 

 nal organization, it was thought useful, to have a report prepared, which would collect 

 together the whole of our present knowledge regarding the fisheries and the biology of 

 the mackerel in the different countries on both sides of the Atlantic. The present writer 

 was then asked by the Council to draw up this report. 



This report on the mackerel is very nearly finished, and it is possible to give here a 

 preliminary account of its principal results, which in some respects may be 

 looked upon as interesting and tending to increase our knowledge of this important fish, 

 as well as giving the basis for future investigations. 



The opinion pronounced by some naturalists, that the mackerel is a non-migratory 

 fish, met with in the surface or deeper layers of the English Channel at all seasons of 

 the year, cannot be maintained. We know of many regions of the sea, as for instance 

 the Kattegat, the western Baltic, the Southern North Sea and the St. Lawrence Bay, which 

 are frequented by the mackerel only for quite a short time, either for the purpose of 

 spawning or for recovering after spawning. On the other hand, such regions as the 

 North Sea and the English Channel are not completely abandoned by the mackerel during 

 the cold season. The schools of fish, which stay in the deeper parts of the North Sea 

 and of the Channel, even in wintertime, are quite considerable and contribute in a re- 

 markable degree to the catches of our trawl-fishermen. 



