232 DISCOVERY REPORTS 



variety of complaints varying from headache, stomachache, dreams, and seasickness to 

 feeblemindedness. 



These observations are sufficient to suggest that the more unusual of the colours met 

 with by us, namely, the bright salmon at Pisco Harbour, the rusty brown south of 

 Callao, and perhaps the khaki near the Guanape Islands, may all be associated with this 

 phenomenon (Plate XVI, figs. 6, 7 and 11). In particular, our observation of rusty 

 brown foam (p. 174) corresponds closely to the remark made above that red aguoje may 

 go away leaving the water frothy. The three observations of abnormally discoloured 

 water met with by us were in contiguous localities : at Pisco the water had a temperature 

 of 19-10° C, and at Callao and at the Guanape Islands the warm wedge was converging 

 with the coast (pp. 192 and 209). Moreover, reasons are given on pp. 216-18 for con- 

 sidering that the counter-current causing aguaje, described by Lavalle, is identifiable in 

 principle with the northern of the two wedges of the present survey. Our failure to 

 notice unpleasant smell and dead fish might not be significant if we were late upon the 

 scene, or if the aguaje were slight. 



Our observation that the orange-coloured water at Pisco contained quantities of a 

 flagellate with red pigment (p. 173), together with the stimulating papers of Hornell 

 (1917) and Hart (1934), provide much food for speculating on the causes of the aguaje 

 phenomenon. The parallelism between the phenomena of Karanir, Sennir and Kedunir 

 on the Malabar coast and of aguaje on the Peruvian coast may be shown by the following 

 extracts from Hornell 's paper: 



... all Malabar fishermen whom I have questioned agree in saying that every year after the passing 

 of the rainy season and the subsidence of the south-west monsoon, if there be a continuance of fine 

 weather for a week or ten days, with plenty of sunshine, and a weak coastal current, the water 

 inshore becomes turbid and discoloured, brownish or reddish in tint; that this water has such 

 poisonous effects upon fish that large numbers become affected and eventually die. The first effect of 

 the poison is to make the fish sluggish and at this stage, as I have myself seen, boys and men crowd 

 to the shore and make great hauls of the dying fish. Fishermen further state that if favourable con- 

 ditions continue, the colour of this foul water changes and becomes distinctly redder, and emits a 

 stench so strong as to be almost unbearable; when this occurs they state that the poisonous influence 

 increases and fishes of kinds not affected during the first onset of the poison, die and are cast ashore. 

 They agree fairly generally in stating that sardines are seldom affected in any quantity, but some men 

 have told me that on two or three occasions, separated by long intervals, they have seen widespread 

 sardine mortality from this cause ; in these cases the sea was covered for miles with dead and dying 

 sardines in enormous multitudes. 



Hornell notes instances of water discoloured by other organisms, but concludes that 

 in almost all cases of widespread fish mortality the discoloration was due to a swarming 

 of euglenids to the virtual exclusion of all other organisms. He notes that bottom-living 

 fish and invertebrates are also cast ashore ; and he also notes that many of the patches 

 of putrefying sardines were reduced to mere frothy ochreous yellow bacterial scums. 



Similar instances of widespread fish mortality with discoloured water have been re- 

 ported from Japan (Nishikawa, 1901) and South Africa (Gilchrist, 1914), though in 

 neither were the organisms producing discoloration identified with certainty. In 



