22 NOllTU SEA INVESTIGATIONS. 



trawlers fishing in the North Sea, the rest coming by railway. It had 

 been stated a few days before, at a conference of the National Sea 

 Fisheries Protection Association, that great numbers of small plaice 

 were being landed at Billingsgate. On the two mornings when I was there, 

 the proportion of small fish was not so large as it had been, and I 

 failed to obtain a box for complete examination. I saw, however, some 

 of the fish landed from a " cutter," or carrier, and the smallest plaice I 

 could see and measure was 6 in. long. This was one of a few lying 

 about the deck, which had fallen from the boxes. I also examined 8 

 specimens brought to me by Mr. Johnson, of these only two were over 

 6 in., the rest were below that size, the smallest being 5|in. I could 

 not find out where these fish were caught, except that it was somewhere 

 on the eastern side of the North Sea. 



I think it will conduce to clearness and precision in considering the 

 data I have given, to keep separate the questions of size and reproduc- 

 tive maturity. To dispose of the latter first, it seems of interest to me, 

 whether it has a practical bearing or not, to try to discover whether 

 immature plaice are found on all grounds, or to what depths and regions 

 they are chiefly confined. I have described samples, 15 fish altogether, 

 from the Great Fisher Bank, and among them were no immature males, 

 and one female apparently immature. The Fisher Bank is from 20 to 

 40 fathoms in depth. In the large sample of 212 fish from the Leman 

 ground, there were eight females possibly immature, and three possibly 

 immature males. In 13 fish from the home grounds, I am not sure 

 that any were immature, and the same is true of the 19 from the 

 Dogger Bank. Of the sample from Markham's Hole on April 15th, 

 some may have been immature, but it was difficult to be sure. On the 

 other hand, in the plaice from the Sylt ground, there can be no doubt 

 that a large proportion were immature, all females under 9 in. certainly, 

 and a proportion of those above that size, although I am inclined to 

 think, for the reasons given, that some had spawned. I have not 

 examined many plaice from the Humber, but there can be no doubt that 

 in the earlier months of the year nearly all of these are immature. 

 As far as we can judge at present, it would appear that the year-old 

 fish, all of which are immature, are not taken at the season of the year 

 covered by the present observation, in any considerable numbers on any 

 of the off-shore grounds. I consider that the small plaice from the 

 Sylt grounds and from the Humber, consist largely, but not exclusively, 

 in the case of the former, of year-old fish. 



To consider now length only. The lower limit of plaice from the 

 Fisher Bank was 12^ in. Of the small fish from the Leman ground, 

 which is opposite the Lincolnshire and Norfolk coasts, the lower limit 

 was 7 in. for males, 9 in. for females, and only one fish in a box of 



