IN THE BAYS ON THE SOUTH-EAST COAST OF DEVON. 481 



have been caught inside, and that after the first year none of the fish 

 were recovered within the bay, although as many as seven ( = 20 per 

 cent, of the total recovered, and 7 per cent, of the total marked) were 

 taken during the second year outside the bay. We see further that 

 after the first half-year the recoveries within the bay were limited to 

 tlie immature fish below 11 inches in length. Since fishes exceeding 

 this size formed a third of the total marked, this feature in the results 

 cannot be without significance. 



If, for the reasons already given, we omit the smallest fishes (7 to 

 8 inches) altogether from consideration, we find that 41 1 per cent, of the 

 Teignmouth Bay fish were recaught, — 31 i per cent, in the first year 

 and 10 per cent, in the second year. During the whole period 11 per 

 cent, were recaptured in the bay and 30 per cent, outside. In the 

 Start Bay experiments only 23^ per cent, of the fish were recaught, 

 — 2H per cent, in the first year and 2 per cent, in the second year. 

 Of the entire number recovered, Ih per cent, had no locality assigned to 

 them, 8 per cent, were recaught in the bay, and 14 per cent, outside 

 the bay (see Table XXIY.). 



The difference between the total percentages recovered (18 per cent.) 

 in the two experiments appears to be an approximate measure of the 

 proportion of Start Bay fish which migrated altogether outside the 

 Brixham trawling-grounds, or acquired habits which placed them 

 beyond the reach of the fishermen during the period under discussion, 

 — 10 per cent, escaping during the first year, and 8 per cent, during 

 the first nine months of the second year. 



The high percentage of fish recovered from the Teignmouth Bay 

 experiments during the second year, coupled with the fact that after 

 the first half-year none of the mature fish were taken in the bay, 

 shows that this bay in no way approaches the conditions of a self- 

 contained area, so far as plaice are concerned; but that it is essentially 

 a rearing ground (or nursery) for young plaice, which leave the bay 

 even before maturity is reached, and do not, as a rule, return to it. 



Turning now to the detailed tables showing the localities of capture, 

 it is obvious at a glance that the Teignmouth Bay plaice, on the 

 approach of winter, migrate eastwards towards the same grounds as 

 those visited by the Start Bay fish. Doubtless the larger fishes 

 which undertake this migration spawn on the same grounds. Accept- 

 ing, however, 11 inches ( = 28 cm.) as the average size at maturity, 

 it cannot escape notice that many of the fishes which had undertaken 

 this migration were too small to be sexually mature (cf. Nos. 219, 225, 

 247, 337, and 343). It will also be noticed that whereas the Start Bay 

 fish tended to return to Start Bay in the following summer and autumn 

 after tlie spawning migration was over, the Teignmouth Bay showed 



