708 



SCIENCE. 



[N. S. Vol. Vlir. No. 203. 



able phenomenon. The water of a considerable 

 portion of the Bay became thick and red, emit- 

 ting an odor almost intolerable to those living 

 nearby. The situation became alarming when, 

 on the 9th and 10th of September, thousands of 

 dead fish, crabs and shrimps were found strewn 

 along the shores or even piled up in windrows. 



At the request of the Rhode Island Commis- 

 sion of Island Fisheries, an investigation was 

 made to determine the cause and extent of the 

 unusual color of the water and of the great 

 mortality of the flsh. The results of this inves- 

 tigation are briefly as follows : 



During the last of August, throughout Sep- 

 tember and a part of October streaks of red or 

 ' chocolate ' water were observed from near 

 Quonset Point and Prudence Island, north to 

 Providence, and, on Bae flood tide, up the See- 

 konk River, nearly to Pawtucket, a range of 

 about fifteen miles. In other parts of the Bay, 

 as far as could be learned, the phenomenon had 

 not been observed. 



On the 8th and 9th of September the water 

 became extremely red and thick in various lo- 

 calities from East Greenwich to Providence, 

 and the peculiar behavior of the marine animals 

 attracted much attention. Myriads of shrimps 

 and blue crabs, and vast numbers of eels, men- 

 haden, tautog and flatfish came up to the sur- 

 face and to the edge of the shore as though 

 struggling to get out of the noxious water. In- 

 deed, the shrimp and crabs were observed actu- 

 ally to climb out of the water upon stakes and 

 buoys and even upon the iron cylinders which 

 support one of the bridges and which must have 

 been very hot in the bright sun. In several in- 

 stances, on these two days, hundreds of blue- 

 crabs were caught by a single individual in a 

 few minutes' time, at the mouth of the See- 

 konk. 



On the following day, September 10th, and 

 for several days afterwards, hardly a live crab 

 or shrimp could be found. Along the shores, 

 however, in the same vicinity, cartloads of dead 

 shrimp were piled up in windrows, and among 

 them were strewn great numbers of crabs and 

 fish of various kinds, especially menhaden and 

 eels. This singular behavior and alarming 

 mortality of marine animals was reported from 

 nearly every station at which the red water oc- 



curred, and from no other station, which indi- 

 cates that the two phenomena are related as 

 cause and effect. 



It was commonly believed that dye-stuffs or 

 other refuse emptied into the rivers at the up- 

 per part of the Bay gave to the water its color 

 and unpleasant odor, but microscopic examina- 

 tion showed that the water was swarming with 

 minute organisms, a species of Peridinium. The 

 Peridinium is reddish brown in color and oc- 

 curred in such excessive abundance that it gave 

 to the water Its peculiar color and odor, besides 

 making it so opaque that one could hardly see 

 a white shell six inches below the surface. 



With regard to the systematic position of this 

 organism there is a difference of opinion. It is, 

 in fact, ranked with the animals by some au- 

 thors and with the plants by others. I have 

 not yet been able to determine the species of 

 our Peridinium. It resembles in many respects 

 Carter's Peridinium sanguineum ; it is much flat- 

 tened, and the anterior end is distinctly bi- 

 lobed, like Peridinium tahulaium, though the 

 lobes are more rounded. Besides a flagellum 

 extending forward from the ventral groove, a 

 very large flagellum lies in the equatorial sulcus 

 and entirely encircles the body. No cilia could 

 be demonstrated. 



After September 9th and 10th, when the great 

 mortality of fish occurred, the Peridinium be- 

 came, for a few days, less abundant, and then 

 increased again until the 23d. There was a 

 heavy rain on the 23d, and on the following day 

 the water was comparatively clear. Since this 

 date it has been more or less in evidence up to 

 the day of writing (October 7th). On Sep- 

 tember 21st the number oi Peridinium per cubic 

 centimeter in the Seekonk River was estimated 

 at 5,880. This was enough to give the water a 

 very noticeable red color. Nevertheless, the 

 marine animals appear not to have been seri- 

 ously affected since September 10th or 11th, 

 though the approach of a streak of red water 

 has, in some instances, interrupted good fishing. 



In the Seekonk River the shrimp and crabs 

 gradually returned, and in about three weeks 

 after the sudden mortality were nearly as 

 numerous as before, though the water was at 

 times distinctly colored. On the 23d some 

 shrimp, oysters and small fish {Fundulus) were 



