12 



Manifestly when the gurnards leave the inshore waters they 

 migrate out to sea, and judging from the results with relation to 

 the migrations of the plaice (report for last year, new series. III., 

 1914) it may be presumed that the outward migration is to the 

 north. The local trawlers obtain small gurnards in small quantities 

 off the coast of Northumberland, but they increase in numbers 

 to the north, and reach a maximum in numbers and in size to the 

 north-east of the Longstone. In this region the gurnards are 

 most plentiful from November to May. This it would not be easy 

 to give in figures without a considerable degree of trouble. It 

 would mean analysing the North Shields records of the local catches 

 made by trawlers, but it indicates in words the experience of the 

 trawlers. 



It may be said therefore that the Northumberland school of 

 gurnards winters offshore opposite the northern part of the county 

 and that the members are spread over a wide area, the small 

 gurnards in shallow water and to the south, and the larger gurnards 

 in deeper water and more to the north. It is not to be supposed 

 that they migrate to a particular spot and stay there, but this 

 is the average result of a general movement. In the spring, the 

 school migrates as a whole southwards and towards the coast, 

 the small arriving first and the larger later as the foregoing investiga- 

 tions have shown. It may further be concluded that the inshore 

 migration results in a concentration of the members of the school, 

 and that during the winter migration the segregation becomes more 

 manifest (fig. 4). 



The other schools on the east coast will probably be found 

 to be related similarly to winter grounds situated to the north-east 

 of the summer feeding area. 



The explanation of the origin of the schools must obviously 

 be sought in the fact that the fish assemble in certain areas for 

 spawning. The spawning season of the gurnard is April to August. 

 The egg is a 'pelagic one, measuring 1-2 to 1-5 mm. in diameter, 

 and hatching takes place after from a week's to a fortnight's 

 oscillation m the tidal currents, resulting, however, in a drift to 

 the south in the regions now under consideration. The larva on 

 emergence measures about 3-5 mm. and is pelagic also. The drift 

 is continued while the larva is growing, but the young gurnard 

 gradually sinks in the water and finally after a period which cannot 



