SEA-FISHERIES LABORATORY. 943 
estuary of the Dee, but these are not included in the 
Lancashire Sea-Fisheries district. 7 
I estimate the area covered by cockle beds at 69 square 
miles in the Northern Division, 19 square miles in the 
Central Division, and 17 square miles in the Southern 
Division. Altogether there are not less than 105 square | 
miles of cockle bearing sands in the whole district. 
It must not be supposed that each of the coloured areas 
on the map represents a bank, or portion of a bank, over 
the whole of which cockles are abundant, and are con- 
tinually being fished for. At any one time the fishing 
is practically restricted to one or more comparatively small 
portions of the bank, and as this becomes exhausted, or as 
the cockles become so small as to be under the legal size, 
the fishing shifts to some other part. .The whole of a 
bank may become exhausted temporarily; this was the 
case in 1899 for the Formby Bank, though in 1897 it was a 
very profitable cockle fishing ground, as much as 180 ewts. 
being removed daily during the winter and spring. At 
present (1899) the cockles on this bank are, as a rule, under 
legal size; they are, however, exceedingly numerous, and 
a season similar to that of 1897 may be expected in 1900. 
Each coloured area on the map represents, in fact, a tract 
over which cockle beds are distributed. The precise posi- 
tion of the beds is continually shifting to some extent, old 
beds being exhausted by fishing, or being sanded up with 
the shifting of the sand banks. New beds are being 
formed, the position and extent of these being dependent 
on the deposition of the spat. The newly-hatched cockle 
leads, for a time, a free-swimming life, and with the 
acquirement of its shell, settles down for the remainder of 
its life in the sand. Obviously the conditions which 
determine the place on which the spat ultimately settles, 
and the consequent formation of a bed, are complex. 
