— 25 — LATER STAGES: PLEURONECTIDS 



As a general impression, the young sole appears to grow more rapidly in length than 

 the young plaice, but the sole being naturally an elongated fish, the relative increase 

 in weight may be less divergent. 



Reference is made to the nocturnal and sand-burrowing habits of the sole, and the 

 figures of the commercial trawlers are tabulated into night and day hauls, with the result 

 that a considerably greater frequency of catches is shown for the former. 



Experimental. 



A Report on Experiments with Covered Nets has appeared this year (2 c). The 

 author deals, amongst others, with two species of Plcuronectidae, namely the Plaice and 

 the Dab. 



The experiments were arranged to determine the comparative power of the different 

 parts of the net in retaining fish of various sizes and species. One interesting result 

 attained is that the number of fish found in the fine meshed net covering the "square" 

 of the trawl, was very small, representing only about. 5 % of the fish (plaice and dabs) 

 and 2.5 % of the haddock and whiting. Even in the case of the "batings" the numbers 

 were not large, as a rule not exceeding 1 1 %. The cod end showed generally by far 

 the largest proportion of escaped fish. 



As regards the separate species, two of the Pleuronectidae, namely the plaice and 

 the dab, are discussed. For each species the length at which 50 % pass through the net 

 is taken as a datum point and the following table gives a comparative statement of the 

 results of the author and predecesssors. 



Table a. Showing for certain species the size at which 50 per cent, of those 



reaching the cod end are retained, as shown by the above investigators and the 



present report. The size of mesh used is given in each case. 



All the original measurements were in inches, and have been reduced to cm. for the sake of comparison. 



