16 



Part III. — Eleventh Annual Report 



to the south of Barra Head. In the Report on the Expedition, 

 Mr Smith mentions the rarer organisms obtained by the trawl, 

 dredge, &c. ; and a list of the mollusca obtained is given by Mr 

 Alfred Brown. 



The Migrations and Rate of Growth of the Food Fishes. 



For a few years experiments have been made on the migrations 

 of the food fishes,, and in the present Report Dr T. Wemyss Fulton 

 describes the results of these. Between 3000 and 4000 fishes, 

 belonging to 22 species, were marked and set free in the sea, most 

 of them being liberated in the Firth of Forth and St Andrews Bay. 

 Of 1250 plaice thus dealt with, 103, or 8*2 per cent., were recovered ; 

 but the percentage rises to 9*9 when the initial experiments under 

 a faulty system are disregarded. The period which elapsed between 

 liberation and recapture varied from two days to 819 days (or two 

 years and three months), the average being 239 - 6 days ; but the 

 extent of the movement does not correspond to the time the fish 

 was free in the water. The number of miles between the points 

 of liberation and recapture varied from practically nil to twent}'- 

 eight, the average being 6*15 miles. The experiments bring out a 

 point of considerable interest in regard to the habits of this 

 important flat-fish. It appears that within the Firth of Forth and 

 St Andrews Bay they move in a definite direction. In the Firth 

 of Forth immature plaice circulate, as it were, along the south 

 shore westwards, and along the north shore outwards or eastwards, 

 some of them passing round Fife Ness into St Andrews Bay. In 

 St Andrews Bay this movement is continued with even more 

 distinctness northwards to the mouth of the Tay, some of the 

 marked fish passing across the mouth to Carnoustie Bay. These 

 experiments concerning the migratory movements of the plaice 

 show (1) that plaice tend to remain within the inshore waters 

 during the period of immaturity ; (2) that while they may travel 

 20 miles in about a year or so, their movement is, as a rule, slow ; 

 (3) that in the areas investigated, their movement is in a definite 

 direction. The results are in agreement with other investigations 

 of the 1 Garland,' and help to complete our knowledge of the cycle 

 of life and movement of this important flat-fish. The number of 

 common dabs marked and liberated was 337, of which eleven, or 32 

 per cent., were recovered. The distance travelled varied from 3 to 

 37 miles, the average distance being 14*5 miles, and the mean 

 period of freedom being 1783 days. The experiments show that 

 this flat-fish is much more active than the plaice, that it moves 

 considerable distances in comparatively short periods, and in- 

 differently in any direction, inshore or offshore, or along the coast. 

 Of 196 codlings dealt with, ten, or 5*1 per cent., were recovered. 

 The mean period of freedom was 74*7 days, and the distance 

 travelled varied from 1 to 52 miles. One travelled 22 miles in 27 

 days, and another 52 miles in 69 days, from the Firth of Forth to 

 Dunottar Castle, Kincardineshire. The results show that codling 

 may remain for considerable periods at about the same place in the 

 territorial waters, or travel long distances with considerable speed, 



