83 
THE MIGRATIONS OF CRABS. 
The general facts relating to the migrations of the edible crab 
I have long been known to fishermen, and also to those who have 
^ considered the question if only in the light of the practices of the 
^ fishermen at difierent seasons. These facts have been stated in 
I. previous reports; they have been clearly indicated in the returns w'e 
I have published for a number of years of the catches of crabs and 
\ lobsters by Messrs. Douglas and Fawcus, and they have especially 
received careful and full consideration at the hands of Dr. H. C. 
■Williamson from the results of a large series of experiments made 
at Dunbar, and of a small number made on the Northumberland 
coast. We do not require any further experiments to be enabled to 
I say that the larger crabs migrate to deeper water in the autumn, 
and return to the inshore -water in the spring. But the results of 
the following experiments, for wdiich we have once more to thank 
Mr J. Douglas, Beadnell, show that the last word has not yet been 
said on the subject; that, on the contrary, further work of this kind 
must be undertaken before we shall be in the position to state the 
subject of the migration of the crab in an adequate manner, and 
especially to discover if there is to some extent at least another 
migration included in the out and-in one with which we are already 
familiar. 
The crabs that -were used by Mr. Douglas were all “casters,” 
that is to say they were undergoing the process of hardening after a 
recent shedding of the old shell or cuticle. They -«’ere captured in 
the first instance in the crab pots, brought to the shore, labelled, and 
liberated at the -v\'ater edge. The label, as in the case of the similar 
experiment with lobsters reported on last year, consisted of a brass 
disc stamped with a number, and tied to the great “cla-sv” with 
copper wire. 
Many of the crabs thus marked in December and January were 
recaptured off the part of the coast where they -v\'ere liberated, and 
at depths w’hich vary with the time of the year, in accordance with 
the above mentioned well-kno-v\’n law of migration. It will be seen, 
however, that the recaptured w'ere mostly males, only three of the 
eleven being females. 
It is in the case of the crabs liberated in October that we have 
to record, if scanty, extraordinary recaptures. On October 11th, 38 
were liberated at Beadnell, and none were recaptured, and it is 
• 1900, 18th Ann. Rep. Fish. Bd. for Scotland. 
