BULLETIN OF THE UNITED STATES FISH COMMISSION. 3*05 



Vol. T, iVo. 20. Washington, 1>. C. A us. 31, issi. 



93.— FOOD OF ?l \« Ivl ICI I., P'll .< ii \Ki>- AND III KltlM. 



By MATTHIAS DUNIV. 



[Froiu Land and Water.] 



For a period of more than twenty years I bave noticed that the whole 

 surface of the sea off our coasts here, in the spring months of the year, 

 at certain times assumes a deep olive color, and I have had oppor- 

 tunities for knowing that in favorable seasons this color is to be found 

 stretching out full L'O miles from land. Our fishermen here call it 

 "cowshiny" water, no doubt because of the similarity which exists 

 between the sea at such times and the excrement of the cow when mixed 

 with water. 



Every inquiry into the matter left me without a clue as to its cause, 

 but on looking carefully into the sea, I found it full of olive colored 

 forms, which for a considerable time I thought were small medusas, 

 but under the glass it was seen they were not medusas, but globules of 

 olive matter, varying in size from ordinary gunshot to that of small 

 garden peas. When I had opportunities of noting them, I found they 

 permeated the water for many yards in depth, and their number was 

 as incalculable as that of the sands on the sea-shore. 



On further observation it was noted that all our surface-feeding fishes 

 were exceedingly fond of tbem as food, and that the stomachs of the 

 mackerel, herring, and pilchards were often found distended with them. 

 And, moreover, that the success of the inshore mackerel-fishery on our 

 coasts in the months of March and April depended on their presence. 



After considerable investigation into the matter, and comparing the 

 undeveloped with the developed spores, I believe I am safe in saying 

 that all these untold myriads of olive globules in our seas, which furnish 

 such abundance of food for the fishes, which color the sea to a consider 

 able depth, and which stretch out so many miles from the land, are 

 nothing more than the fully developed seeds or spores of the Mclano- 

 spermece, or olive seaweeds. 



The number of spores thrown off by a single plant in one season is 

 prodigious. The last I observed was a Fusis serratus, and the figures 

 to represent them would be not less than two millions. The few books 

 I have on the weeds make no remarks on rain-water playing any part 

 in the development of the spores. But it now seems probable that 

 there can be no fructification of the spores of the olive and green sea- 

 weeds without the genial showers of the spring and the summer. 



April 18, 1885. 



Bull. U. S. F. 0., 85 20 



