SEA-FISHERIES LABORATORY. 187 



less on the nursery-grounds than it is on the grounds 

 further offshore, so that successive shoals of fish arriving 

 on the latter grounds will tend to lower the growth-rate 

 which would be characteristic of the offshore region. If 

 this outward migration were irregular, so that a much 

 larger number of slowly-growing fish arrived on the 

 grounds during July, we should have the apparent nega- 

 tive increment in the growth-rate that the Table shows. 

 Altogether all the data available seem to show that the 

 Nelson Buoy plaice fishery during the summer and autumn 

 is one for fish that have grown up to the first, second, 

 and third years of life on the inshore nursery-grounds, 

 and which migrate out to sea during the months of May 

 to July, so as to form the extensive shoals that are fished 

 on the grounds in question. 



This fishery practically comes to an end in September 

 or October. We have practically no reliable statistics of 

 the quantities of plaice landed monthly from these 

 grounds — the fishery is one carried on to a very large 

 extent by second-class sailing vessels, so that it is, so far, 

 an almost impossible task to attempt to trace the yield of 

 the grounds. The experimental hauls made by the 

 "James Fletcher" indicate, however, that plaice are not 

 at all abundant on the Nelson Buoy grounds earlier in the 

 year than May, nor are they abundant after October. 

 During the months of October and November the fish 

 begin to desert these grounds, and the migration paths 

 followed depend, to some extent, on the age of the fish. 

 The smaller fish appear to move back inshore, where they 

 apparently become " lost " — they probably hibernate, 

 burrowing in the sand at the bottoms of the deeper 

 channels in the Bays and Estuaries. From the Nelson 

 Buoy grounds the larger plaice appear to migrate into 

 the Ribble Estuary, into Morecambe Bay to the North, and 



