14 REPORT ON OYSTER CULTURE 



Considerable difference of opinion exists as to the cause of this 

 decrease — some authorities contending that it is altogether due to 

 over-dredging — others to failure in the natural production of spat. 



It would be tedious and confusing to enter into the various 

 opposite theories (many of them deserving of attention) as to the 

 cause of the decline. 



Both of the above influences have doubtless adversely affected 

 the production of oysters. If at the period when reproduction takes 

 place a rise or fall of the temperature beyond a certain degree 

 occurs, especially if such change be sudden, it is likely to be 

 attended with injury to the spat — no doubt there have been years 

 when the spatting season was cold and variable, and storms are 

 also said to have taken place at the same period in other years. 

 Conceding that the scarcity is in part due to the foregoing cause, 

 it is a natural one, and one which we cannot well deal with ; but 

 the principal cause of the scarcity is attributable both in France 

 and England to over-dredging; and this we can deal with, to a 

 certain extent counteracting its effects by wise legislation. 



No better illustration can be given than the advantageous posi- 

 tion which Ireland occupies when compared with either of the 

 other countries. That her natural beds have suffered much less 

 from exhaustion may be attributed in a great measure to the en- 

 forced close time and other salutary regulations made by the Com- 

 missioners of Irish Fisheries, which are not in existence in England, 

 and only lately came into operation in France. 



Various branches of Oyster Fisheries. 

 The oyster fisheries may be divided as follows : — 



Firstly. — Natural banks where without any action on the part 

 of man oysters are propagated. 



Secondly. — Banks partly natural and partly artificial — as those 

 in the rivers at Auray and other places in France, and of 

 Essex and other places in England — where the produc- 

 tion is aided by laying down fresh cultch and stock and 

 keeping the beds clear of dirt and vermin. 



Thirdly. — Foreshore cultivation — where the spat from oysters 

 on natural banks is saved or caught on collectors placed 

 for that purpose. 



Fourthly. — The method of cultivation in enclosed spaces such 

 as Lake Fusaro in Italy, at Hayling, the Isle of Wight, 

 and other places. 



Natural Banks. 



France. — To obtain information with respect to the natural 

 banks the Commissioners visited Arcachon, La Teste, the He 

 d'Oleron, the He de Be, Auray, Concarneau, St. Brieux, Granville, 

 Cancale, L' Orient. 



Channel Islands. — Jersey. 



England.— -The Solent, Langston, Emsworth, Heme Bay, Mil- 

 ford, Tenby, Bristol, Beaumaris. 



Ireland.— Arklow, Wexford, Waterford, Dungarvan, Cork, 

 Kinsale, Baltimore, Bantry Bay, Kenmare, Tralee, Shannon, 

 Ballyvaughan, Kinvarra, Galway, Koundstone, Cleggan, Bailing- 



