'21 
It will be convenient to rearrange the data with reference to 
ilaice and dabs, and also with reference to station and the above 
fortnightly periods (Tables VI., VII. and VIII.), to indicate more 
graphically when the experiments were made in the successive years 
and the influence of seasonal variation. 
The dates when Skate Roads was visited each year w r ere as will be 
seen so closely identical that the results appear in the first and fourth 
periods. Unfortunately, however, it was not always possible to 
experiment in this area, especially in June. It is at once apparent 
that there were two occasions when the catches of plaice were 
abnormally large, viz. : in 1894 and in 1903. With these exceptions, 
which do not alter the conclusions with regard to the two periods, 
the experimental hauls appear to be typical of the station, and it is 
plain that while seasonal variation occurs, it is not usually a marked 
one. The small catches of dabs, so characteristic of this bay and 
Goswick Bay, are yet sufiiciently consistent to justify the conclusion 
that they also arc typical. Jt is worth noting here that while the catch 
of plaice referred to above in 1891 was not accompanied by a similar 
increase of dabs, that of 1903 was ; and a comparison of the other 
results in the two tables will indicate that in some instances both 
showed an increase or decrease, in other the two forms exhibited 
more or less divergence in relative numbers. 
The effects of seasonal varation are better illustrated by a com- 
parison of the results obtained at the more southerly stations, but 
it is plain that the limits of variation do not exceed what would be 
expected from areas liable to gain and loss from the areas immediately 
outside. 
Alnmouth Bay was experimented in on three occasions, in 1891, 
1900, and 1902, and in the case of plaice the returns point to an 
emigration in July, followed by an immigration in August. The 
catches of dabs also exhibit similar gains and losses, but the seasons 
are not always coincident with those noted for plaice. In the case 
of the three visits in the years mentioned above, for example, the 
numbers recorded for dabs indicate almost exactly opposite periods 
of increase and decrease compared with plaice. 
Experiments have been made in Druridge Bay with great 
regularity during the U years, and the effects of emigration and 
tnmigration on the catches are apparent from a consideration of 
the returns. The evidence shows in the first place that there is 
variation in the incidence of the immigration, and gives reason in 
