OYSTER-CULTURE IN AUSTRALASIA. 563 



together with the royalty (recently discontinued) charged 

 upon the oysters taken off them, yielding a very considerable 

 revenue to the Government. 



Taking the year 1886 by way of example, and as a fair 

 average, 14,774 bags, representing roughly (reckoning from 

 1,200 to 1,500 to the bag) about 22,000,000 oysters, were 

 derived from the tidal waters of New South Wales during that 

 twelvemonth. The royalty collected on these oysters amounted 

 to £2,216, and the rents and deposits for leased areas and on 

 applications for leases to £3,641, or a total of £5,857. This 

 oyster-harvest derived from her own tidal waters does not, 

 however, suffice for the requirements of New South Wales, 

 statistics for the same year quoted showing that 4,906 bags, 

 or close upon 7,000,000 oysters, were in addition imported 

 from New Zealand and Queensland. Within the last few- 

 years the number of imported oysters has increased. A con- 

 siderable check, moreover, has been given to the indigenous 

 fisheries of New South Wales through the appearance of a 

 disease in many of the most prolific grounds, which either 

 destroys the oyster or renders it unfit for food. 



The latest official returns (Eeports, 1889-90) received during 

 the preparation of this lecture do not, I regret to say, indicate 

 any improvement in the condition of the New South Wales 

 oyster-fisheries. On the contrary, the output from her tidal 

 waters for the years 1888 and 1889 has fallen as low as 9,184 

 and 6,914 bags respectively. The number last quoted only 

 equals the importations from New Zealand and Queensland 

 for the same period. As shown by these figures, urgent neces- 

 sity undoubtedly exists for strenuous efforts being undertaken 

 in sufficient time ; and I would advise the Government to pre- 

 serve the New South Wales oyster-fisheries from absolute 

 destruction. 



Disease in Oysters. 



The form of disease that is apparently chiefly responsible 

 for the great deterioration of the oyster-fisheries of New South 

 Wales is characterized by the presence within the oyster- 

 shells of patches of mud, which are more or less completely 

 covered in by a shelly or membranous redeposit, one or more 

 small worms being almost invariably found enclosed within 

 these mud-cavities, which maintain a communication witli 

 the outer water. These worms are usually credited with 

 being the prime origin of all the mischief, wliicli is accordingly 

 denominated the " worm disease." This so-called " worm 

 disease" is not prevalent in the oyster-beds of Queensland; 

 but, judging from a passing acquaintance I made with it in 

 New South Wales, and all the facts concerning it that have 

 been published, I am strongly inclined to believe that this 



