19 



animal life, on account of the oxygen which is given off ; they 

 are indeed probably the basis of the food supply for fish and all 

 other animals in the ocean. Their presence in quantity, 

 therefore would have the effect of attracting the fish, especially 

 such fish as Mullet and Sardine, which again would be followed 

 by the larger fish, which prey upon them. 



It would seem, however, that in some circumstances, the 

 presence of large quantities of vegetable matter in the sea 

 may lead to organic decay and the suft'ocation of fish, as in 

 the case of " red water." The following incident for which 

 I am indebted to Mr. M'Lachlan, a resident of many years' 

 experience in the fishing industry at Stumpnose Bay, seems to 

 bear on this point. After narrating the case in which fish 

 were found in " red water," he continues : " At another time 

 I saw hundreds of large Steenbras fish, floating with their heads 

 above water in a similar manner. The fishermen landed lots 

 of them. I went afloat with a small boat, and to my surprise 

 saw numerous Klip-fish and Hottentot-fish floating about in a 

 stupefied condition. At the same time our fishermen picked 

 up large quantities of Galjoen-fish on the beach at Schell Bay. 

 In this instance, the water where the fish were found looked 

 a thick greenish colour, with small particles of matter resem- 

 bling a kind of mica. The night previous there had 

 been a thunderstorm. My opinion was that very probably a 

 thunderbolt had burst into the sea during the night, thus 

 causing the fish to be stunned." 



The " thick greenish water with small particles of matter 

 resembling a kind of mica " is an accurate enough descrip- 

 tion of the appearance presented by the masses of diatoms in 

 the sea, found in the survey of the Pieter Faure on the west 

 coast on several occasions, and it looks as if the fish found were 

 in a state of suffocation. 



That masses of diatoms do decay in such a manner on the 

 West coast will appear very probable from the incident related 

 as occurring at Walfish Bay. 



14. Under this last heading are included a number of very 

 striking cases of destruction of fish attributed often to sub- 

 marine disturbances, cold currents, etc. They seem to indicate 

 a possible explanation of cases of general decrease in the fish 

 supply in South Africa and are dealt with in detail. The most 

 striking instances of this are recorded from the west coast, in 

 and near Walfish Bay. The first case on record is an occurrence 

 which took place at Swakopmund, a comparatively exposed 

 seaport in German territory, a little to the north of the 

 excellent and sheltered harbour of Walfish Bay. The following 



[C.P. 6-'i4.] 



