XXXIX.-PRESENT STAGE OF THE SALMON EXPERIMENT IN 



TASMANIA. 



By Morton Allport, F. L. S., F. Z. S., &c. 



(Read November 12, 1877.) 



[Papers and proceedings and report of The Royal Society of Tasmania, for 1877, 



pp. 109 to 114.] 



Though grilse weighing from 3 to 7 i^oiitids have, during the last four 

 years, been taken in the Derwent, how is it that no mature salmon — that 

 is, fish weighing from 15 to 30 pounds, have been captured ? This is a 

 question frequently asked both here and in the neighboring colonies, 

 but it will be necessary before attempting to answer it to refer to what is 

 known of the early life-history of the salmon in Europe and Tasmania. 



It has been calculated by able British authorities that in specially 

 good salmon rivers, such as the Tay in Scotland, not more than one egg 

 in every 1,500 deposited ever becomes a salmon, the diminution in num- 

 ber taking place chiefly during the earlier stages of life, and especially 

 during the journej^ of the smolt to the sea, and the first few weeks of 

 their residence there, though even the grilse appear liable to have their 

 number considerably decreased by the attacks of marine enemies before 

 their return as veritable salmon. 



The limited number of mature salmon we can yet have in the Der- 

 went might, therefore, alone account for their non-cai)ture, but we must 

 add to that disadvantage the want of adequate appliances to ensnare 

 large-sized fish. The chance of taking one with the rod is infinitesimal 

 while the fish are scarce, the fishermen scarcer, food very abundant, and 

 the difficulties with which the angler in the Upper Derwent has to con- 

 tend great. The one or two fine-meshed seine nets worked down the 

 river, though well adapted to scrape out smolt, are quite unfitted for the 

 capture of salmon, as they are shot so as to leave a considerable space 

 between the net and the shore, and take so long to haul that the wary 

 old salmon would, before the end of the net reached the land, pass round 

 one or the other, and so escape. 



The majority of the 18 or 20 grilse caught have been taken in an 

 ordinary grab-all net, having a mesh of such a size that only the fish of 

 from 3 to 5 pounds weight can mesh themselves, and no larger salmon 

 is at all likely to be taken by the same net, as in this method of fishing 

 it is essential that the fish should be able to get the gill covers through 

 the mesh, or by backing it can at once free itself. If a grab-all net, 

 having a mesh of two and a half inches from knot to laiot, was used, 



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