180 THE PRODUCTIVITY OF THE SEA [PART II 



stock can be " raised " from unit areas of different soils under 

 different conditions, but such knowledge hardly exists with regard 

 to marine economic produce. 



I will collect here what data are available with regard to 

 the productivity of the sea. One turns naturally to the fishery 

 statistics in attempting such estimations. If we can ascertain 

 what quantity of fish is landed annually from the North Sea, 

 we may have the data for a first essay at the productivity of a 

 fishing area. A year or two ago such information was not very 

 accessible but during the last two years the International Council 

 for Fishery Investigations have published fairly complete statistics 

 and I quote these here^. 



Productivity of the North Sea fishing grounds. In the 

 year 1904 the fishing fleets of Russia, Norway, Sweden, Denmark, 

 Germany, Belgium, the Netherlands, England, Scotland and Ireland 

 caught in the North Sea and landed at European ports 967,433,000 

 kilogrammes, or 951,900 tons offish. The area of the North Sea 

 is equal to 547,623 millions of square metres^; we find then that 

 the yield of this fishing area was (in 1904) 



17'6 kilogrammes per hectare per annum, 

 or, putting the same thing in English measures : 

 15 lbs. per acre per annum. 



If we take the average value of the fish caught as about 0'234 

 shilling per kilogramme, then the money value of the North 

 Sea was Is. 6d. per acre per annum. 



Now this is certainly a minimum value for the yield per unit 

 area of the North Sea in fish flesh. Fishing boats do not go to sea 

 to make scientific deductions but to earn money for their owners, 

 and they only bring to land such products as command a ready 

 sale in the markets. Thus hosts of small and inedible fish are 

 caught and immediately shovelled overboard. Shellfish (lobsters, 

 crabs, shrimps, molluscs, &c.) are not included, for the difficulties in 

 the way of estimating the catch of these creatures are too great. 

 Probably the quantity of fish included in the statistical returns is 



^ See Bulletin Statistique des Peches Maritiines des Pays du Nord de VEurope. 

 Vol. I. Copenhague, 1906. 



2 Karsten, " Neue Berechnung mittl. Tiefe Ozeane," Dissertation, Kiel, 1894. 



