158 DESTRUCTION OF IMMATURE FISH. 



nectes flesus, and one small sole caught in tlie harbour at low tide 

 as before. The sole was 18 mm. long, the flounders 15 to 19 mm. 

 The difference represents the growth which had taken place in the 

 fortnight elapsed. From the fact that after two or three days' 

 search during these spring tides Mr. Dunn was only able to find a 

 single young sole, it may be inferred that after reaching the size of 

 18 mm. the small soles move into somewhat deeper water, and are 

 no longer to be found within the low-water mark of spring tides. 



" I searched the shores of Sutton Pool and the mouth of the Plym 

 estuary at Plymouth, and found no specimens of young flounders 

 such as were so plentiful at Mevagissey ; but some boys brought 

 me two specimens of Pleuronectes flesus on May 31st, 10 mm. long, 

 taken at low water on the muddy shore of Sutton Pool." 



There are three points of particular interest in this Report, first 

 the preponderance of the comparatively worthless flounder over the 

 valuable sole ; secondly, the indication given of the rate of growth 

 of both sole and flounder ; thirdly, the inference as to the change of 

 habits of the young sole. Much more information is required on the 

 last two heads. Undoubtedly the minute fish migrate from the beach 

 to deeper water in search of food, but next to nothing is known of 

 their history and movements at this time. It is known that small 

 flat-fish, between three and six inches in length, are commonly caught 

 by shrimp trawls working in one to three fathoms of water, and by 

 seine nets hauled inshore. It has already been pointed out that 

 when undersized flat-fish are captured by large beam trawls, they 

 almost invariably belong to small and valueless species ; and it is im- 

 portant to note that the same rule holds good, though in a lesser 

 degree, for shrimp trawls, — at any rate it is so in Plymouth Sound. 



The shrimp trawls used at Plymouth have an iron beam from nine to 

 twelve feet long, and the mesh of the net is about half an inch square 

 at the cod end. "Whilst working at the life-history of the sole during 

 the last twelve months, Mr. Cunningha^m engaged the shrimp trawlers 

 of Plymouth to bring him all the small soles caught by them in the 

 Sound. The number brought in was not large, never more than 

 three or four in a day, and as a rule they were not brought in on 

 more than one or two days in a week. Thus the take of undersized 

 soles in Plymouth Sound is not large, and as the shrimpers at once 

 throw overboard all the soles which are too small to be of market 

 value, no destruction is done. On several occasions the fisherman 

 of the Marine Biological Association has ti-awled in Cawsand Bay 

 and elsewhere with the expi^ess purpose of getting very young soles. 

 The results of his fishing are instructive, and the following cases 

 may be regarded as typical. On August 15th, 1888, the trawl was shot 

 several times in Cawsand Bay, where it was reported the shrimpers 



