RECENT REPORTS OF FISHERY AUTHORITIES. 215 



nearly on the edge of the brow, but while they are still transparent 

 pelagic fish, they are 10 to 12 mm. long." The length at which the 

 metamorphosis is complete, appears to vary from 10 mm. to 13 mm, 

 Petersen was unable to find the young plaice of 12 mm. before the 

 month of May, and concludes that the larvti; hatched in November take 

 six months to pass through their pelagic stage. The same does not 

 hold, however, for the turbot, the brill, the flounder, and the sole, in 

 all of which the spawning season begins later than in the case of 

 the plaice. 



Further, the young plaice of 12 mm. in length are always found close 

 in on the shores, and never in water of two fathoms and over. From 

 this fact Petersen draws the conclusion that of the pelagic fry in the 

 sea only those which happen to be near the shore at the time when 

 metamorphosis takes place can survive. It is the physical conditions 

 then, and not the presence of enemies, which causes that enormous 

 destruction of larvoe which undoubtedly takes place. 



The young fish belonging to the "0 group," which have all reached 

 the length of 12 mm. by the month of May, grow to a length of 2—4 

 inches by the following autumn. In the succeeding winter they cannot 

 easily be found on the shores, and it is suggested that they bore down 

 deep into the sand where the seine cannot reach them. By the end 

 of their first year the young fish migrate into deeper water, and this 

 migration probably begins in the winter months. An investigation 

 made at Aalbek in July, 1893, showed that the plaice were larger 

 the deeper the water examined. Summarising the results of this 

 investigation it was seen that besides the " group," which were found 

 in water of less than 2 fathoms, there was a "1 group" from 2i-2 

 inches at 5 fathoms, and a " 2 group" from C|-10 incbes, which began 

 to appear in water of 8 fathoms. 



The different groups are not, however, found in all the seas. On 

 the contrary, while as we have already seen, the " group " is entirely 

 absent from the Baltic, the plaice in their second and third years are 

 present in considerable numbers. The largest specimens (14 in.) found 

 in the Baltic, probably represent the 3 group, and the size at which 

 the 2 group meets tlie 3 group, is set down at 8 to 9 inches. On 

 the other hand, fish of 3 years old and over are not found in the 

 Northern Cattegat in any numbers "without much searching"; and it 

 seems clear that owing to persistent over-fishing there has been in 

 recent years a decrease in the size of the plaice caught in the Cattegat, 

 As Petersen remarks in pathetic italics, "they do not get time in the 

 Cattegat " — cut off, as it were, by ruthless fishermen before they attain 

 their prime ! The fact that the " 3 group," which is almost absent from 

 the Cattegat, and but poorly represented in the Baltic, is found in the 



NKW SERIES — VOL. IV. NO. 2. Q 



