218 RECENT REPORTS OF FISHERY AUTHORITIES. 



factor."* And again, "If we fisli the plaice while they are small, we do 

 not get so great a profit from them as we might and ought to have. 

 In this only, so far as I can see, the ' destniction ' consists." \ 



It is of interest to notice that the view here set forth appears also 

 in the discussion on the desirability of a close time for crabs and 

 lobsters. I And if it is assumed for any species — (1) that the provision 

 made in nature for keeping up the numbers of individuals is more than 

 sufficient, and (2) that owing to 7iatural inlluences, the number of 

 surviving groivn-up individuals is fixed and relatively small, then it will 

 follow that the continual destruction caused by man must of necessity 

 lead to a decrease in the number of large individuals, and that this 

 decrease cannot be met either by artificial propagation, or by the imposi- 

 tion of a small size limit. These two assumptions appear to me to 

 underlie the view which our author puts forward as the "growth 

 theory"; and the first of them implies that there is, under natural 

 conditions, an excessive wasteful production of young fish. 



Our author further points out that, in respect of the plaice, both 

 theories will lead to a similar practical conclusion — the imposition of 

 a size limit; though the effective size limit, from the point of view 

 of the "growth theory," will be higher than that which is required 

 by the "propagation theory." This, however, does not hold good in 

 all cases. The eel-fishery, for instance, consists wholly in the capture 

 of eels which have never spawned. " The propagation theory would 

 be obliged to require a size limit of at least 20 inches, in order to 

 protect the stock of eels satisfactorily; hut then the males could not he 

 cauf/ht at all."^ The growth theory, on the other hand, would be 

 content with a lower limit. 



It will be seen that the questions raised by the discussion of these 

 different theories are of great practical importance. They are among 

 the scientific problems which call for settlement, before sure guidance 

 can be given to the legislator. 



* Loc. cit. pp. 61, 62. {In all quotations the italics are Petersen's.) 

 t Loc. cit. p. 57. 



+ Cf. p. 186, this number of Journal, answers of fisherman to cross-examination by 

 Messrs. Pannett and Mally. 

 § Loc. cit. p. 82, footnote. 



