SOME RESULTS OF THE INTERNATIONAL FISHERY INVESTIGATIONS. 451 



Biological Investigations. 



The results of the strictly biological investigations carried out under 

 the auspices of the International organization are less novel than those 

 hydrographical results to which we have already referred. Sea fisheries 

 research, both in Great Britain and on the continent of Europe, has in 

 the past been largely concentrated on the elucidation of the life 

 histories of fishes and other edible marine animals. Beginning in 1865 

 with G. 0. Sars' classical investigation of the spawning of the coil on 

 the fishing grounds off the Lofoten Islands, this work was developed at 

 first principally by Mclntosli and the St. Andrews school of zoologists; 

 and when fisheries investigation received official sanction and support 

 in this country, it was very actively pursued in Scotland by the 

 naturalists of the Fishery Board, and afterwards in England by the 

 Marine Biological Association. AVhen in 1902 the International 

 Investigations were commenced a very considerable store of knowledge 

 of this branch of fishery science already existed,* and subsequent work 

 in the countries participating in these researches has been devoted 

 to filling up lacuucC in those results and in synthesizing the investiga- 

 tions by the adoption of methods of research on a larger scale than 

 was previously possible and by new forms of apparatus. 



It is unnecessary to recapitulate here the main features of our know- 

 ledge of the life histories of northern fishes.f The reader will 

 remember that the great majority of North European food fishes 

 reproduce during a limited period of the year — three months or so, some 

 time betwee-u the end of the year and midsummer — the precise dates 

 and durations of these breeding seasons depending both on the species 

 of fish and on the localities under consideration. The exact incidence 

 of the breeding season is not constant from year to year, but varies, 

 and one of the main results of the International hydrographic investiga- 

 tions has been to associate the onset and duration of the breedint; 

 season with the hydrographic condition of the portion of the sea 

 considered. Generally speaking, the majority of British food fishes 

 spawn during the months March to June. 



The eggs produced by these fishes are now fairly well known, though, 

 of course, our knowledge on this point is not quite exhaustive. Most 

 fish eggs belong to the pelagic type — that is, they are lighter than sea 

 water of normal constitution and fioat at or near the surface. But the 



* This ha3 been admirably summarized by P. P. C. Hoek in No. 3 of the Publications 

 de Circonstancc, Auf:;u.st, 1903. 



t See also Cuuiiin^'haurs Marketable Marine Fishes, 1896 ; Holt's Account of the 

 Grimsby Tj-awl Fishery dnihUahvil by the Marine Biolo^'ical Association); and Mcintosh 

 and Masterman's Life Histories of the British Murine Food Fishes, isy?. 



