SEA-FISHERIES LABORATORY 67 



gave in the last Quarterly Report, he directed attention 

 to the following points : — 



(1) The prevalent, or modal, lengths of the plaice 

 taken month by month on the various grounds by means 

 of a 6-inch trawl net. Those from Rock Channel, in the 

 Mersey, were the smallest by far, and those from Red 

 Wharf Bay, in December, were the largest, with the 

 exception of some catches made off New Quay, in 

 Cardigan Bay. The percentages of fish of each length, 

 in centimetres, are given in the Report. The lengths in 

 inches can be obtained by dividing the lengths in centi- 

 metres by 2\. 



(2) The variation in length from month to month. 



(3) The variation in " condition " from month to 

 month, and on the various fishing grounds. As a rule the 

 condition was worst, in the case of immature fish, in 

 January and February, and best in July and August. 



(4) The small percentage of sexually mature, or 

 spawning, fishes taken in inshore waters — except in Luce 

 Bay, and in the Firth of Clyde. 



(5) The ages of the fish, the great majority of the 

 plaice in the inshore grounds off the West Coast of 

 England and Wales being less than three years old. 



(6) The influence of the size of the trawl-net mesh. 

 In spite of the enormous numbers of small plaice taken by 

 the 6-inch trawl mesh in some areas, like Rock Channel 

 for instance, there is no clear evidence for the conclusion 

 that the 6-inch mesh is wastefully destructive. The 

 plaice are small, and are below the normal in "condition " 

 because they are so abundant. If they could be " thinned 

 out " by transplantation it might be of advantage to the 

 fisheries in general to enforce the 7-inch mesh. But so 

 long as they cannot be transplanted, it is open to doubt 

 whether the use of the larger mesh would lead to any 



