344 



Part III. — Thirteenth Annual Report 



observed in those caught at a more considerable distance (50 miles and 

 upwards) from the coast; the soles of hauls 11-13 of 1893 were perhaps 

 slightly larger than the other ones; the soles of haul 6-9 of 1894 were 

 decidedly the largest ones of that year. 



This, however, was much more evident with the plaice caught at a 

 greater distance from the shore. While the average size of all the plaice 

 caught in 1893 was only 22*5 centimetres, the plaice of the hauls 11-13 

 measured 29*6 centimetres. In 1894 the medium size for all the plaice 

 measured was only 21*6 centimetres, but those of hauls No. 6-9 (50-63 

 miles from shore) had an average length of 28*2 centimetres. The plaice 

 caught in 1893 were, curiously enough, larger than those of 1894. 



For the dab, such an increase could not be made out. The medium 

 size of those measured in 1893 was 19*6, but those of the more- distant 

 hauls, No. 11-13, measured 19 centimetres only ; in 1894 the length of 

 the dabs on an average was 18 '4, and exactly the same medium size 

 characterised the specimens of the hauls No. 6-9. 



In a few cases only it was possible to measure all the dabs and plaice 

 in a haul, but a fairly representative portion was always investigated. In 

 view, however, of the experimental character of both cruises and the 

 relatively small number of observations made, it would be hazardous, 

 Dr Hoek states, to base wide conclusions on these measurements; but 

 some inferences are drawn from the results obtained : — 1. Of two nets, 

 the cod-ends of which have equal-sized meshes, but the foremost part 

 having larger meshes in the one than in the other net, the one with the 

 larger meshes brings up larger soles than the other. 2. The size of the 

 plaice and of the dabs taken with nets, the meshes of the foremost part 

 of which are different, does not show the same difference as with soles ; 

 plaice and dabs of any size once in the net appear to have no chance of 

 escaping. 3. The difference in size of the soles taken (in July to 

 September) with the same net, at points more or less distant from the 

 coast, seems not to be very considerable. The soles at the greater dis- 

 tances were somewhat larger than those caught nearer the coast, but this 

 may be caused by chance. 4. The difference in size of the plaice taken 

 (in July to September) with the same net, near the coast, and at a dis- 

 tance of 50 miles and upwards from the coast, was found considerable 

 in both expeditions. This difference being found both years rather 

 large, there cannot be reasonable ground to doubt that it arose from the 

 size of the fishes at these places being different. 5. The dabs caught at 

 a greater distance from the coast were not found to be larger than those 

 found at a less considerable distance. 



Somewhat similar results have been found in some other parts of the 

 North Sea, but almost nothing was previously known — in a scientific 

 sense — of the trawl-fishing in the North Sea to the east of the fourth 

 meridian. A large fleet of small Dutch fishing-boats is constantly 

 working the grounds between that meridian and the west coast of 

 Holland. When the weather is fine they go as far as the Broad Four- 

 teens, and even farther ; but for the greatest part of the year they stay 

 eastward of the fourth meridian. Is the damage done by their fishing 

 really so great as is believed at the west side of the North Sea ; is it 

 larger in some months of the year than in others ; does it affect both 

 round-fishes (cod, whiting, haddock, hake) and flat-fishes, or only flat- 

 fishes, and, of the latter, some species more than others, or all of them 

 in an equal way 1 Should great damage be done, the question arises 

 whether or not it will be possible to remedy its effects — but the first 

 thiug that is necessary is to know the facts well. Such knowledge can 

 be obtained only by the constant use, for a series of years, of a sea- 

 worthy steamer fitted up for the purpose. It appears that for several 



