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MIGRATIONS OF THE LOBSTER AND THE CRAB, 



By ALEXANDER MEEK. 



Lobster. — From the reports we have published from year 

 to year it will be evident that we have attempted at different 

 times to mark lobsters with a view to obtaining some direct informa- 

 tion as to their migrations. The results are not at all definite, 

 but so far as they go, they may be said to point to a migration 

 of the females when they become mature to a short distance north- 

 wards on the east coast. 



During the last year or two it has been our habit to mark the 

 lobsters used in the Laboratory for lobster culture after the 

 larvae have been liberated, and the shell has been cast. Although 

 they were kept in a condition of confinement for several months, 

 they were liberated as soon as they were hard enough after ecdysis 

 to bear the label. Of a number marked in 1913, the results as 

 published in the last report indicated migrations of the females 

 to a mile or two to the north. This year, No. 270 was returned 

 to us on June 2nd in the berried condition. She was liberated 

 on August 18th, 1913, in Cullercoats Harbour, and was recaptured 

 just to the south of St. Mary's Island, a httle over two miles to 

 the north. Her size at the time of recapture was 29 cms. 



This specimen is interesting for two reasons ; first, that it 

 gives definite information as to the period intervening between 

 casting and coming into berry, and, secondlj^ that it indicates 

 at least a slight migration to the north of the mature females. 

 None of the males which have been marked has, as in the case 

 of the crabs, indicated any tendency to migrate. 



Crab. — The last two reports gave the results of the marking 

 of crabs at Beadnell at the end of 1912. An interesting example 

 came into our hands this year. This was a female. No. 428, which 

 was marked on December 1st, 1912, at Beadnell, and which^was 

 recaptured two miles east of Dunbar on April 26th, 1915. It will 

 be noted that she was liberated just after an ecdysis, that the 



