NORTH SEA INVESTIGATIONS. 91 
With a view to satisfy themselves as to the wisdom of granting 
such concession, the Committee asked me to carry out a series of in- 
vestigations on the subject, for which purpose Mr. J. W. Woodall, a 
member of the Committee, and one whose interest in the welfare of 
our fisheries as well as in marine biology for its own sake is too 
widely known to need more than a passing reference here, offered 
the use of his steam yacht, the “ Vallota,” R.Y.Y.C., for a month. 
The Council of this Association accorded the necessary permission, 
and I propose here to give a brief account of the work done and the 
conclusions arrived at. 
The “ Vallota” draws only 4 feet of water, and is therefore 
eminently suited for work in a shallow estuary, such as the Humber. 
The gear we used consisted of a professional shrimp- or prawn- 
trawl, beam 13 feet, mesh $ inch “from knot to knot,” or 34 inch 
square, in cod end. No pockets. Hemp ground-rope 92 inches in 
circumference. False bellies of leather, cork, and coarse netting. 
We also carried a small fish-trawl of ordinary pattern, 173 feet 
beam, and a naturalist’s trawl, 9 feet beam, of sprat-mesh lined with 
mosquito net, and fitted with a heavily chained ground-rope. 
The services of a professional shrimp- and prawn-trawler were 
secured to pilot the yacht, point out the different grounds, and work 
the gear. 
The chief object of the investigations was to arrive at a know- 
ledge of the amount of destruction of young fish of valuable kinds 
which would be likely to ensue from the regular working of the 
grounds by shrimp- and prawn-trawlers during the season then 
closed by the Committee’s bye-law, or during such part of it as was 
included in the time when the investigations were carried on, viz. 
from October 19th to November 17th. For this purpose a number 
of hauls were made on all the grounds with the professional gear, 
and the results accurately recorded, the modus operandi being as 
far as possible assimilated to that of the small sailing-boats engaged 
in the industry, The fish-trawl was used on the grounds affected by 
sole-trawlers, so as to ascertain the quantity and sizes of fish present 
during the current season, and also in various parts of the river not 
usually accessible to sailing-boats, partly with a view to obtaining 
all possible information as to the distribution of fish in the river, and 
partly, im conjunction with cod ends of different mesh, to test the 
relation between size and pattern of mesh and size of fish caught. 
As these operations do not intimately concern the subject under 
discussion, I shall not refer to them further in this place. The 
naturalist’s trawl was used at the same time as the fish- and shrimp- 
trawls, in order to find out what fish or other organisms passed 
through the meshes or beneath the ground-rope of those engines, 
