244 



Part III. — Seventeenth Annual Report 



As the group is fairly well represented numerically, the averages 

 deduced will be approximately correct and represent the main growth- 

 rate of the plaice to October 19th. The only other instance where the "0" 

 group is recorded from the Northern Kattegat in 1893 is contained in 

 Petersen's Table V., when 17 specimens were captured at Aalbeck on 

 July 8th. They have an average size of 1*117 inches, which corresponds 

 with the average for July 9th in Table VII. (difference only 0*087 inch). 

 The distinction of the "0" group in the above Tables is in accord with 

 Petersen's own classification, and is undoubtedly correct 



The " 1 " group, comprising fishes of more than one but less than two 

 years of age, is also indicated in Petersen's Table III., and I give here a 

 summary from that Table as regards this group. 



Table VIIL, showing Particulars regarding the " 1 " group as contained in 



Table V. 



Date. 



May 1 



June 10. 



July. 



Aug. 



Sept. 21. 



Range of the group, Danish 

 inches, ----- 



lf-3i" 



2r-3f 







3r-5r 



Total numbers in the group, 



40 



41 







38 



Avge. size in Danish inches, 



2-619 



2-982 







4-407 



Owing to the presence of this " 1 " group, it is evident that the fishing 

 was conducted in sufficiently deep water for the "0" group, and this may 

 also be said as regards the group in question here. In conformity with 

 what has already been said, it may be argued that if the fishing had been 

 extended to deeper water, larger fishes would have been captured. Owing 

 to the mode of fishing in this case, it is probable that all depths have 

 been examined within a certain area, and though, the greatest depth has 

 not been stated, it is evident that if the net had been shot still further 

 out, particularly on September 21st, a larger portion of a third group 

 would have been captured, which now is only indicated as existing 

 between 5J-7J inches. But as on that date — September 21st — the "0 " 

 group is present and also part of the " 2 " group, the " 1 " group ought to be 

 duly represented. On June 9th (Petersen's Table V.) a group of plaice 

 was captured by a sandeel-net near the Scaw. The fishes ranged from 2 to 

 i\ inches, and had an average size of 2-796 inches. Petersen has appar- 

 ently been in doubt as to the age of this group, and has placed his " 1 " 

 group mark on the 4-inch line, thereby suggesting that the fishes in question 

 belong to an " 0 " group — that is to say, under one year old. But the 

 proper "0" group at this time has been found to exist at the range f-iuch- 

 1-inch, and has an average size of about 0'848 inch (see Table VII. ). The 

 group captured at the Scaw must therefore be more than one year old, 

 and its average size corresponds well with the 1 " group for June in Table 

 VIII. But while the great mass of these fishes are representatives of the 

 " 1" group, there are not sufficient details to show whether specimens of any 

 other group may be included, and much importance need not be attached 

 to its average value. No further information is supplied regarding this 

 group in the Northern Kattegat for June 1893, but from what has 

 already been said it is evident that the two youngest groups of plaice in 

 these waters in June had an approximate position as indicated, the one 



