730 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [6] 



belonging unquestionably to the same species. Finally, to be silent on 

 no point, I will add that, from the experiments of MM. de Montaug6 

 and Bonchon-Brandely (experiments which do not seem to me to have 

 been conducted with sufficient scientific precision), it would appear that 

 the spermatozoa of the Portuguese oyster cannot fecundate the ova of 

 the Ostrea edulis. I can affirm that, during my stay at Arcachon, I 

 never observed any fact which would make me believe in a change in 

 the oyster i)roduced in that district. 



To sum up, I do not believe in a cross between the two mollusks; but 

 I must add that the introduction into our waters of the Portuguese 

 oyster does not strike me as unattended with danger. It is known that, 

 when two species are compelled to live side by side in a limited space, 

 there springs up between them what a celebrated naturalist has called 

 the struggle for existence. This struggle must, sooner or later, end in 

 the discomfiture and disappearance of the weaker species. Under these 

 conditions if the gryphcea and the ordinary oyster are brought together, 

 the latter must necessarily succumb. 



The Portuguese mollusk is unquestionably more robust, more endur- 

 ing, and, I should say, more prolific. The facility with which it propa- 

 gates its species is really very remarkable. 



It is known how the Portuguese oyster took possession of a por- 

 tion of our coasts: a few hundreds of them having been accidentally 

 brought to the embouchure of the Gironde soon formed considerable 

 beds. Even this year I have been able to see collectors placed on the 

 shores of the isle of Ol^ron, covered almost exclusively with Portuguese 

 spat. 



I think, therefore, that in the generality of cases the culture of the 

 graphoea, if carried on in the vicinity of pares of ordinary oysters, may 

 lead to serious evils. And yet I saw nothing at Arcachou leading me 

 to think that the Portuguese oyster would supplant the ordinary 03'ster. 



Here is, in addition, the very disinterested testimony of M. Lhopital, 

 commissary of marine, to whom I had imparted my fears on seeing the 

 daily increase in the introduction of the Portuguese oyster into the 

 basin of Arcachon. He wrote to me recently as follows: 



" Previous to the question of hybridization that of the entire occupa- 

 tion of the collectors, by the Portuguese oysters, had produced commo- 

 tion among the maritime population of Arcachon. Some parqueurs had 

 even demanded that the introduction of these oysters into our waters 

 should be absolutely prohibited, and in the beginning of 1878 the min- 

 ister directed an inquiry into the matter. 



" It was ascertained that the danger apprehended was not serious. It 

 is more than twenty years since enormous quantities of Portuguese 

 oysters were introduced into the basin of Arcachon, which came either 

 directly from the mouth of the Tagus or from the Bay of Corogne, or 

 from England, or the embouchure of the Gironde. Well, with perhaps 

 the exception of one or two years, it has be^q remarked that the repro- 



