f)22 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



{[]) Ww iicrociorciits (the littoral currLMits or local coast euijciits); and 

 (■4) tlm zoik-nrrcnfs (the local planktonie streams or veiy crowded animal 

 roads). 



Halicurrents or ocean streams. — The nneiiual distribution of plank- 

 ton in the ocean is in j^reat part the direct result of the oceanic 

 currents. In general the proposition is recognized as true that the 

 great ocean streams, which we briefly designate as halicurrents^ effect 

 a greater accumulation of swinuning organisms aiul thereby are 

 richer in i)lankton than the hali.sla.sa or ''still streams," the extensive 

 regions -which are inclosed by them and relatively free from currents. 

 For a long time the richness in plankton which characterizes the Gulf 

 Stream on the east coast of jSTorth America, the Falkland Stream on 

 the east coast of South America, and the (iuinea Stream on the west 

 coast of Central Africa, has been known. Less understood and investi- 

 gated than these Atlantic streams, but also very rich in varied plankton, 

 are the great streams of the Indian and Pacific oceans, the Monsoon 

 Stream on the south coast of Asia, the Mozambiciue Stream on the east 

 coast of South Africa, the Black Stream of Jai^an, the Peru Stream on 

 the Avest coast of South America, etc. 



It is very difficult, from the numerous scattered accounts of the 

 pelagic fauna and flora of these great ocean currents, to form a general 

 picture of them, but it is now possible to draw from them the conclu- 

 sion that generally the i^lankton of the haJicurroit.s, qualitatively as 

 well as quantitatively, is richer than the plankton of the halistasa, or 

 the great oceanic sea basins around which flow the great streams and 

 counter streams, and which meet the first glance on every recent map 

 of the marine currents. * 



In defending this proposition I rely especially upon the rich experi- 

 ence of the two most important plankton expeditions, of the ChaJlenf/er 

 (6) and of the Vettor Pisani (8), and also upon my own comparative 

 study of several hundred plankton samples, Avhich were collected in 

 part by Murray, in part by Cai)t. Kabbe, in the most diverse parts of 

 three great oceans. The planktonie wealth of the great halicurrents is 

 most remarkable at the jilace where they are imrrowest, when the 

 masses of swimming animals and plants are most closely pressed 

 together. Highly remarkabhj here is the opposition which the rich 

 pelagic fauna and flora of the stream forms in (pialitative and quanti- 

 tative relation to the sparse population of the innnediately adjacent 

 halistase. As the temperature and often even the color of the sea 



* Tho systoniatin hiDlogicMl investigation of tlii^ hnJistm^n Rooms to me to form one 

 of the uearest and most prossing problems of plaiiktology, and also of oceanography. 

 Apart from tlie smaller and little iuvestigatod Arctic and Antarctic regions, iii all 

 five great areas of <jniet -water onglit to he distinguished, namely: (1) the North 

 Atlantic halistase (with the Sargasso Sea) ; (2) the South Atlantic (between Benguela 

 and Brazil streams); (3) the Indian (between Madagascar and Anstralia); (1) the 

 North Pacific (between (hilifornia and China), and (5) the South Facitic haliataae 

 (betAveen Chili and Tahiti). 



