cr.rries the economy of the lobster fishery. This profit will be 

 affected if the population of hatching lobsters is kept lav;-. 



With the present population we have reason to believe that the 

 average annual increase in number of lobsters will depend on - and 

 viill be approximately proportional to - the supply of brood. If 

 we shall increase the lobster population, we must increase the 

 supply of brood. 



We can obtain an increase in the nT:inber of spavming lobsters 

 by protection of the' egg -bearing lobster or by raising the mniiiurn 

 measurements. . -t 



The first method is easily un^'erstood - and is approved of by 

 the fishermen* It is, however, difficult to cr.rry out. The egg- 

 bearing lo^•ster is very valuable and to thravr this out will cause 

 a heavy economic loss; also the law might easily be evaded by 



scraping the spawn off the lobster. 



.i ■ 



By raising the minimum measurements we save both the male and 

 the ferxile young lobsters. The present 3:iinim\im length is 21 centi- 

 meters, and as we knovr that the female lobsters norma.lly are not 

 crpable of propagation until they have reached a size of 22-24 cm., 

 it is obvious that' we v/oulr" get considerably more spavming lobsters 

 by raising the minimum measurement - especially as our measurements 

 sho'.T that the largest quantity of the catch consists of just the 

 smallest indixi-iduals . We would get a larger population of sparm- 

 ing lobsters, anal also the lobster Y>rould obtain a higher v/eight per 

 individual - and thereby incredse in value. 

 « * ■ '■ 



Table 2 shovra the distribution (per lOOO) in proportion to 

 the size. 



Length in cm. Jomfruland 



Number Vfeight .. ' ' etc. (see Table, p. 42) 

 Ililogr. %' / 



The ••question ic \m5-i ether t he higher weight and the larger numiljer 

 of spavming lobster will compiensate for the loss which the fishermen 

 would suffer by throv/ing back lobsters with an increased minimum 

 measurement of, for instance, 1 cm. Our tagging experiments shov/ 

 that T/ithin a jrear we recatch about 44 per cent in nmaber. This 

 corresp-^nds to about 60 per cent in weight. But after a Virhile v/e 

 recatch part of the lobsters which we did not recatch the first year 

 and so on. An example v/ill illustrate this condition, but first we 

 shall -find out hov;- many lobsters if the crtch are betxreen 21 and 22 

 cm. - and what w-eight percentage these have of the vrtiole catch. 



If we increase the minimum measurement we have to throw out 

 28 per cent of the number, e*g. 21 per cent of the v/eight in the 

 waters around Jomfruland. At Arendal the figures are respectively 



91 



