54 
The plaice sent from London market (1904), Grimsby market, 
and Aberdeen market must be included amongst tbose which have 
left our district although it is unfortunately impossible to tell where 
they were caught or m what direction they had migrated. In the 
case of No. 873, the information which was furnished enabled me to 
make an attempt to discover the history of the fish, and it can be 
said that it is more than probable that the fish was captured in the 
Moray Firth. It was sent to the Lowestoft Laboratory from Man- 
chester wholesale fish market, with a note that it was found in a 
barrel from Nairn, Scotland. I wrote to Dr. T. W. Fulton with 
regard to the capture, and his reply was " The fishery officer reports 
that the marked fish you referred to must have been caught between 
Burghead and Nairn, at no great distance off, as the Nairn fishermen 
usually fish for plaice in that locality." 
Of the nine which are recorded in the table (or to be more 
certain of the eight — it is possible that the last one, the numbered 
label of which was wanting, belonged to the 1904 group, as its size 
indeed suggests) three have not migrated. These show also that 
the size about which migration may take place is from 29 to 35 cm. 
or 11^ to 12 in. All the Northumberland marked fish above 35 cm. 
have migrated from the district ; below that size they exhibit on 
the whole no tendency to migrate except within the bays, and only 
rarely move for short distances up or down the coast. The trawling 
experiments have also demonstrated that plaice, and dabs, as well, 
migrate outwards and inwards in territorial waters. The immigrants 
to the region so near the shore as the trawling stations are usually 
derived from the slightly deeper water immediately outside, but 
they include occasionally representatives from extra-territorial 
waters. These latter give reason for saying that there is in the 
summer, and at other seasons also, a general inshore movement 
affecting the fish fauna of the regions outside the district as well as 
that within it, followed by an outward migration — a general advance 
and retreat. 
Our experiments show also that when the migratory impulse 
does come it may carry the fish very many miles from the Northum- 
berland coast, and although it cannot be said to be universal, the 
direction of migration is usually northerly. 
Dab. — It will be seen from the above returns that a large number 
of dabs have been marked, principally during the last two years. 
Of the 9 marked in 1903, one was recaptured, a female of 21 -G cm., 
