FRESHWATER FISH EPIDEMICS IN QUEENSLAND RIVERS. 1(7 



take a fit and swam towards the shallow water or bank of the 

 river, where they died. Their eyes bulged out and they appeared 

 to be sightless. Inside the mouth was of a bluish colour. Their 

 gills and scales appeared to be normal. The fish upon being 

 opened up were found to be very fat. Neither the jewfish 

 nor the freshwater tortoises, which Avere plentiful in the river, 

 were affected. The epidemic, which commenced shortly after 

 the heavy rains, was still present at the time of writing, i.e., 

 for a period of from three to four weeks. On 22nd March this 

 outbreak wass reported in the " Brisbane Courier." 



On 23rd April Mr. Mills again wrote reporting that the 

 mortality was not so pronounced and that difficulty had been 

 experienced in obtaining for us a fish in the moribund state. 

 Eventually a specimen, identified by Mr. J. D. Ogilb}'' as 

 Therapon carbo Ogilby & McCulloch, was sent down. 



In the middle of May a rise in the river was occasioned by 

 rains up country, sweeping away all signs of the outbreak, which 

 had apparently asted for almost two months, being at iis 

 height at the end of March. 



On 7tli August Mr. Mills informed us that the mortality 

 had reappeared at the end of July, fish d\'ing in large numbers. 

 The senior author v.as av.'ay from town at the time and the 

 junior author vsas not able to arrive at Longreach until 17th 

 August. On the following day, aithougli prolonged search Avas 

 made up and down the large lagoon adjacent to the town, only 

 two moribund fish were obtained, one being a Therapon hillii 

 Castln., the other a bony bream, Nematalosa elongafa Macleay. 

 Dead and rotting fish were exceedingly abundant, especiaU}^ 

 at the lower end of the lagoon, where they were piled up 

 against the crossing. Although close search was made, no more 

 dying fish were obtained. On several days hauls were made 

 AAith a small-meshed net in the hop? of obtaining diseased 

 specimens. An astonishingly large number of fish Avere caught 

 in each haul but none appeared diseased, so the majority Avere 

 returned to the AA-ater, a fcAv being kept for examination. 

 Three species, Plectrop)liies ambiguus Richardson (golden 

 perch or j-elloAv-belly), Therapon hillii (" black bream "' or 

 grunter), and Nematalosa elongata (slender bony bream) Avere 

 by far the most abundant. Xo catfish Avere caught in these 

 hauls. 



During the Aveek pre\nous to the 18th, men had been 

 mployed raking the fish out of the riA^er and burning them. 



