of the Fishery Board for Scotland. 



121 



majority, if not all, of the small crabs cast during the summer. Certain 

 soft crabs came under my notice which had evidently been labelled, for 

 they showed a gap torn in the edge of the carapace at the part where 

 the label was usually attached. None of the small hard crabs were 

 recovered later in the year than September, that is to say later than 

 the casting period ; one was captured in August, a second in September. 

 One apparent exception to the statement is the crab No. 8 in Table XI. 

 It had, however, been free only fourteen days when it was captured in 

 November. The probability, then, is that casting accounts partly for 

 the non-recovery of the small crabs. 



In the Tables, in addition to the distance and direction from Dun- 

 bar of the place where each labelled crab was retaken, the depth of the 

 water at the spot is also given. The fishermen, although able to give 

 only very approximate particulars of distance and direction, can give 

 within small limits the exact depth at which their creels are fishing. 

 The direction from Dunbar and the depth of water are surer guides 

 to the locality of capture than the distance as estimated by them. 



In order to show graphically the results of the experiments, the places 

 where the crabs have been recovered have been marked on a chart of 

 the sea near Dunbar (Plate IV.). Two marks, each of two different colours, 

 are employed to distinguish the different groups of crabs. Thus the black 

 marks relate to those crabs which were recaptured in the months of 

 August to February inclusive; the red colour designates the crabs 

 caught in the period April to July inclusive. No crab was recaptured 

 in March. The little discs (red and black) denote crabs which were set 

 free at the mouth of the harbour (Table X.); the crosses (red and black) 

 refer to crabs which were set free at some distance from Dunbar 

 (Table XL). 



The chart, Plate IV., first of all shows that the labelled crabs 

 caught from August to February were, with two exceptions, all got 

 out in 18 to 25 fathoms water, while those caught in April to 

 July were got in an average of 8 fathoms. Of the winter crabs, 

 101 in number, 89 were found in water of over 20 fathoms in 

 depth, ten in 18 to 19 fathoms, one in 17, and one in 16 fathoms. 

 The depth, then, for these crabs was 18 to 30 fathoms. Of the 27 summer 

 specimens, 19 were found in 4 to 8 fathoms, three in 10, three 

 in 13, and one in 16 fathoms. The crabs recaptured in the 

 months August to February will be first discussed. If now we 

 consider the crabs set free at the mouth of the harbour (Table 

 X.), and represented in the chart by a disc, we see that they 

 were mainly recaptured between a northerly and north-easterly direc- 

 tion from Dunbar ; and from the fact that three specimens, Nos. 28, 

 29, and 30, which had been free for two days only, had travelled from the 

 harbour 2 miles and 2| miles respectively in a north-easterly direction, 

 it is very probable that the massing of these crabs just beyond the twenty- 

 fathom line, and in an area bearing N.E. from Dunbar, points to the 

 crabs having gone out in that direction. The crab which had travelled 

 farthest, No. 40, was found 6 miles to the north of Dunbar after 59 days. 

 While the majority, then, had apparently moved off to deep water in a 

 north to easterly direction, three had taken an easterly and three an 

 east by south course. The results then point to a definite direction, 

 viz. N.E., taken by the crabs in going from the shallow water at the 

 mouth of the harbour out to the ground beyond the twenty-fathom line. 



Most of the crabs which were put away at some distance from 

 Dunbar were set free from 1 to 3 miles in an E. by N. direction. 

 Two lots, numbering 30 and 26 individuals, were liberated at 

 miles and 2 miles respectively east of the harbour, and a third lot, 



