SUMMARY AND GENERAL REPORT. 



The work of the Laboratory during the past year has 

 naturally been restricted, but the members of the staff, in 

 addition to identifying themselves with military activities in the 

 district, have been useful to the Board and the inshore fisher- 

 men in connexion with regulations relating to fisheries, and 

 the question of possible distress. The Laboratory's motor boat 

 " Evadne " has since the end of last summer been lent to the 

 Admiralty. The Report therefore deals for the most part with 

 work done in the Laboratory. 



This Report, like the last, is concerned to a large extent in a 

 consideration of the principles underlying the migration of fish. 

 In the paper on the migrations of the gurnard, it is shown that 

 tlie 3^oung are gathered in a region which may be called the 

 recruiting ground, and that up to the time of maturity they 

 migrate inshore in summer and offshore in winter. After the 

 denatant (see note page 14) drift of the egg and larvae the 

 recruits of the Northumberland school of gurnards migrate inshore, 

 and still denatantly. This is followed at the end of the second 

 summer by an offshore and contranatant migration. Thereafter, 

 with growth, the contranatant winter migration becomes more 

 and more marked, the larger immature gurnards moving further 

 to the north and into deeper water, the result being a segregation 

 according to size and depth. When mature the gurnard 

 migrates still further in the contranatant direction, and it 

 is more than probable joins the spawning migrants of a 

 school of another region, if not at the first, at a subsequent 



