REPORT ON THE WORM DISEASE AFFECTING THE 

 OYSTERS ON THE COAST OF NEW SOUTH WALES. 



By Thomas Whitelegge, 



Fellow of the Royal Microscopical Society ; Zoologist, Australian Museum. 



At the request of the members of the Fisheries Commission, I, 

 by permission of tlie Trustees of the Australian Museum, 

 recently paid a visit to Newcastle with a view to inquire into 

 the so-called oyster disease, which is caused by the presence of a 

 small marine worm, identified by Pi'of. Haswell, of the Sydney 

 University, as Polydora ( Lucodore) ciliata (Johnston). On my 

 arrival at Newcastle I was taken over the various oyster beds by 

 Mr. Curan, the local Inspector of Fisheries, who did everything 

 in his power to assist me. I am also indebted to Messrs. Gibbons 

 and Anderson, two of the principal oyster lessees, for their kind- 

 ness in providinfif me with boats and dredges. 



fflie Infected Area. 



Althougli the worm is very generally distributed, having been 

 met with in various situations, from about lialf-tide line to moder- 

 ately deep water, still tlie principal home of the worm appears to 

 be on the mud flats about low-water mark. The oysters from this 

 region were invariably infected with the worm, particularly those 

 which lay loose on the surface or partially bui-ied in the mud. 

 Whilst those oysters which were fixed to some solid substance, 

 and elevated ever so little above the surface of the mud were com- 

 paratively free from the pest. 



During my stay I examined about fourteen oyster beds, which 

 I need not particularize, suffice it to say that the worst are the 

 bare mud-flats and the artificial beds in deep water. The latter 

 are composed of oysters collected on the banks of the river, and 

 probably tlie majority were obtained from the mangrove flats, as 

 they would be more easily gathered, inasmuch as they are ;iot, 

 in that locality, fixed to any solid sulistance. From an examina- 

 tion of a very large series of these oysters, I am convinced that 

 they were infested with the worm before th(?ir removal, as the 

 evidence of disease was in nearly all cases deep-seated and below 

 the lines of growth made after being laid down. The natural beds 

 — only a short distance from the artificial ones — are fairly free 

 from disease ; and, further, they appear to overcome the worm 

 when attacked, quickly enclosing it with a thick layer of shelly 

 matter before it has time to establish itself. From what I ascer- 



