10 



averaged 360 per hour, the catch of November 1st, 4 ; at Druridge 

 the summer catches for the same period averaged 49, the November, 

 3. Figure 2 conveys the impression that the wave of gurnards 

 reaches Ahimouth first and passes onwards to Blyth, that the spring 

 or eSiYlj summer maximum of Druridge expands into the single 

 maximum of Btyth, and that Druridge again expresses hj a second 

 maximum the return of the gurnards to tlie north. It is tolerablj^ 

 certain that in 1913, in August, Druridge suffered a temporarj^ 

 relapse in the number of gurnards for it was visited twice during 

 the month, and on both occasions the same feature was experienced. 

 It is probable therefore that when the gurnards arrive in shallow 

 water they continue for a period to move southwards along the 

 coast. This would serve to explain the double maximum in Ahi- 

 mouth Bay, and this it must be said has been noted to be general. 

 But it is not necessary to conclude therefrom that the gurnards 

 of Druridge migrate to Blj^th, but rather that the maxima express 

 the general movement to the south when the fish reach the coastj 

 and that Blj^th Hes near the distal end of the school. 



The details of measurements are given in the same Report 

 (Table II., images 12 to 22), and those referring to Alnmouth Bay 

 are represented in the form of a diagram in figure 3. The curves 

 indicate with reference to size the catch per hour each month. 

 It is not necessary to point out that there is an increase fculminating 

 in August, and that already in Sex^tember the greater part of the 

 fish had already left. The figures for August were so great as to 

 render it necessary to show the curve in a broken manner as wiU 

 be readily evident. 



This j)resentation of the conditions in Alnmouth Bay for 1913 

 makes it clear that the migration concerns mainly the young, 

 immature gurnards. Of these also it is evident that the smaller 

 appear first, and that the size gradually increases during the season. 

 The small number of older and mature fish appear late. It is 

 also clear that they depart in the same order. The conclusion 

 is warranted then that the young small fish come from a region 

 near at hand, while the larger ones migrate from distances which 

 increase with size. It has been natural to assume from such a 

 presentation of results of experiments that the change in the 

 maximum from 16 cm. in June and July to 18 cm. in August indi- 

 cates growth. But it is not in the light of the facts of the migra- 



