6 



THE SCIENTIFIC AND ECONOMIC ASPECTS 



may be desirable. In the first place it may be remarked that 

 the occurrence of such a Copepod as Auomalocera palicrsoiii 

 R. Temp, and the Euphausid Nictyphancs coiichu Bell in 

 stomach contents cannot, in the absence of plankton observa- 

 tions taken in the area immediately on, or adjacent to the fishing 

 grounds, be accepted as evidence that the fish had come in from 

 deep water, since inshore visitations of such plankton species 

 have been recorded. From a careful consideration of Mr. 

 Dunn's observations it is evident that considerable importance 

 as an article of diet is attached to material described as " the 

 spores of the olive seaweed." The present authors have been to 

 some considerable pains to determine the true nature of this 

 organism, but without success. From information derived 

 from Mr. Howard Dunn, of Mevagissey, it would appear that 

 in former years this appeared in large quantity in Mevagissey 

 and St. Austell's Bays about the beginning of June, its paucity 

 or abundance apparently affecting the extent of inshore 

 migration of pilchard, and that the fish appeared to feed 

 ravenously upon it until the supply was exhausted. Of recent 

 years this organism has not appeared, and in the opinion of 

 Mr. Dunn and certain other observers interrogated upon the 

 subject, the decline of the fishery may to a certain extent be 

 attributed thereto. 



The only suggestion which may be hazarded as to the true 

 nature of this organism is that it is either the Flagellate 

 Phacocysiis glohosa Scherfel or the Chlorophycean 

 H alosfhaera viridis Schmitz— in greater probability the 

 former. 



Numerous observations of the more or less abundant 

 occurrence of Phaeocystis at the International Cruise Stations 

 situated in the Great West Bay, at Plymouth, etc., have been 

 recorded,^^ but unfortunately none of these positions lie within 

 the usual pilchard fishery area. During the early part of 

 June, 1913, the present authors, whilst tow-netting in St. Ives 

 Bay, met with a profusion of Phaeocystis, the same organism 

 appearing to be absent from other stations investigated on the 

 South Coast at the time. From information derived from an 



12 Vide, Plankton tables Inter. Investigations, "Bulletins Conseil Inter, 

 pour I'exploration de la Mer. " 



