FISHERIES 253 



adapted to life in warm water, might cause serious damage if 

 allowed to spread to the principal drainage basins by such means 

 as the transference of fry to private waters. Control has now been 

 instituted in the principal centres of fish introduction: in Natal 

 there is an Inland Fishery Officer, Mr. Day; in Uganda Captain 

 Pitman, the Game Warden, is responsible for fisheries, and in 

 Kenya, the post of Fish Warden, formerly held by Mr. R. E. Dent, 

 is now occupied by Mr. H. Copley. The value of a central research 

 organization for the colonial territories has been suggested above. 



PRESEPvVATION OF FISH FOR MARKET 



The possibility of improving native measures of preserving fish 

 has already been discussed. This section is primarily concerned 

 with the preservation offish on a large scale for commercial purposes. 

 The researches in progress at the Torry Research Station at Aber- 

 deen, one of the laboratories under the Food Investigation Board 

 of the Department of Scientific and Industrial Research, will 

 doubtless have a bearing on African developments. 



When large supplies of food fishes are obtainable close to port, 

 the possibilities of extending the market for fresh fish are clearly 

 worth careful consideration. This field of development might not 

 only extend to the inland centres of population which are accessible 

 by rail transport, but also might include markets overseas. The 

 necessary conditions for such a development are (i) supplies of very 

 fresh fish in suitable quantities at the point of distribution, and 

 (ii) the means for preserving quality unimpaired up to the point 

 of consumption. It is possible that the first of these conditions is 

 fulfilled by the large quantities of soles which are known to be on 

 the grounds close to several South African ports, while the second 

 might be achieved by the process of brine-freezing and cold storage. 



In the cold storage of fish for long periods the conclusions from 

 research are that fish must be frozen rapidly when quite fresh, 

 must be stored at a low temperature (less than minus 5°F.) and 

 subsequently must be thawed rapidly. Common salt brine, which 

 does not reach a solid state until its temperature is below minus 

 5°F., is highly suitable for freezing fish, which will remain pala- 

 table and marketable for periods of five, six, or even seven 



