SEA FISHERIES LABORATORY. 147 



complete bouchot system would be — but to aid them, to 

 rescue from destruction the minute mussel fry in order 

 that they may be later on stripped off and bedded out. 



The number of our mussel beds might so be largely 

 increased, and it ought to be remembered that these 

 mussel beds are not valuable merely because of the mussels 

 they produce, but also because of the effect which they 

 have upon other fisheries by enriching the waters with 

 numerous larval and other minute forms of life. Mussel 

 beds become centres of attraction to numerous other 

 invertebrates producing swarms of living things which 

 are most valuable as food for young fishes, as well as for 

 the mussels on the bed. 



II. Cockles. 



529 cockles {Gardium edule) have been examined iD the 

 Laboratory during the past year in order to find out the 

 food and times of spawning of this important shell-fish. 



As was stated in the first report, (1892) the stomachs of 

 a very large proportion of the individuals are always empty, 

 and this seems to be the case throughout the year. It is 

 difficult to give an opinion as to the reason for this, as it 

 can scarcely be due to digestion after capture, seeing that 

 mussels collected at the same time and sent to the Labor- 

 atory along with the cockles frequently contain food. 

 Possibly a further examination of the cockles made at the 

 moment of collecting may throw some light on the matter; 

 it will be kept in view during the ensuing year. 



In regard to the spawning time of the cockle it is diffi- 

 cult to give a definite period as we find them sexually 

 mature nearly all the year round. Towards the latter 

 part of the year measurements were made of the ovarian 

 ova; and the inside of the shell and mantle cavity were 

 carefully washed out before opening the animal so as to 



