65 



Dab.— The dabs marked in 1903, 1904, 1905, 1906, 1907 and 

 1913 have given results which are rather different. Those caught 

 shortly after marking (see figure 7) made little or no migration, 

 but during the subsequent winter a strong tendency to a southerly 

 or denatant migration was shown. In the October following 

 marking, out of twelve examples recaptured six females were 

 stationary, 1 male had migrated north for 7 miles, two males and 

 two females to the south and one to the east. In the following 

 winter months similar results are apparent, three having been 

 got to the north and three to the south, and the southing is to a 

 greater distance in the case of two of these. In the early part of 

 the succeeding summer, four females had apparently made no 

 migration, one female had migrated far to the north and two to 

 the south. Later in the summer, two large dabs were got to the 

 north, and the dabs under 30 cm. to the south. In November, 

 after an absence of more than a year, a female of 25 cm. was got 

 about the same place where marking took place. It may be said 

 then that the immature and the spent fish are decidedly denatant. 

 The probability is that the northerly migrants, as has indeed been 

 found on enquiry, are mature fish. 



The strong tendency to a southerly migration of the immature, 

 especially during the winter, is in remarkable contrast to that 

 of the other species. During the winter they move south and 

 east, and winter for the most part in depths of about 30 fathoms. 



There is or usually is a conspicuous migration of the dabs 

 from the inshore waters, and in spite of the great distance travelled 

 during the winter, the return appears to be usually to the same bay 

 or one in the immediate neighbourhood. We at once associate 

 the southerly migration with the peculiar distribution of this 

 species in the bays and in the district as a whole. 



The plaice and especially the flounder during their sojourn 

 in the inshore region are liable to enter fresh water. The flounder 

 moves into rivers in October, and may remain in estuaries during 

 the winter. Plaice in many cases have been proved to enter 

 brackish water on their return from the offshore migration, that 

 is to say, from February to April. Indeed, in both cases they 

 may remain for a longer period at least in estuaries. Whatever 

 the attraction maj 7 be in these species, it is probably a general 

 one affecting all to some degree. A potamotaxis has been observed 



