OYSTERS AND OYSTER FISHERIES OF QUEENSLAND. 267 



into the water again, under the impression that their life is destroyed. As a matter of fact, 

 each of the five finger-like processes separated from the starfish's body is capable of growing 

 into a fresh starfish, so that by the process of dismemberment the further multiplication of the 

 species is accomplished. If only the lambs' tails docked by the Australian pastoralist could be 

 induced to re-grow the lamb, on the same happy principle, millionaire squatters would soon 

 become a drug in the market. To encompass the certain destruction of the starfish, it is 

 desirable that they should be carried to land and be deposited above the reach of the tide. They 

 may also be killed immediately, by immersion in fresh water. 



Certain species of sea-urchins, or sea-eggs. Echini, have been occasionally accredited with 

 oyster-eating proclivities. Their habits, however, are essentially herbivorous, and the only 

 injury they might possibly, but very improbably, do to oysters is that of piercing the very 

 young and fragile shells, with their sharp spines, in passing over them. 



Many varieties of Queensland fish prey more or less extensively, though not exclusively, on 

 oysters. Among these may be mentioned the family of the toad-fishes, Tetradons, porcupine fish, 

 Diodons, leather-jackets, Monacanthi, and the several varieties of breams, Pagridae. The most 

 destructive fishes on the oyster-banks are, however, undoubtedly the Sting-rays, or " Stingarees" 

 as they are popularly denominated, belonging to the shark tribe and referable to the genus Trygon. 

 The common dark brown species, Trygon pastiiiaca, is probably the greatest delinquent in this 

 direction. It abounds on the low-lying banks throughout the oyster-growing districts, and commits 

 serious havoc among the young stock, under the action of its pavement-like crushing teeth. A 

 more typical oyster-eating member of the shark tribe, that abounds in the southern colonies and 

 is occasionally taken in Moreton Bay, is the so-called Port Jackson shark, Ccstracioii Philippi. 

 It is of a tawny-brown colour, with an abnormally large head and projecting brow-ridges, and has 

 a strong sharp spine developed in front of each of the two dorsal fins. It rarely exceeds a length 

 of five feet, but is provided with powerful crushing jaws of greater strength even than those of 

 the Rays, with which it easily breaks up the largest oyster-shells. On certain of the Tas- 

 manian Government oyster reserves, and private beds, it has wrought such havoc, that the oysters 

 were only saved from entire destruction by fencing them round with wire netting. With reference 

 to its oyster-eating proclivities, the species is known in Tasmanian waters by the name of the 

 "oyster-crusher," while in some parts of Victoria it is called the "pig-fish." In testimony of 

 the peculiar hardness of its palate, it may be mentioned that in the neighbourhood of Port 

 Jackson, New South Wales, it feeds extensively on the spine-covered sea urchins, its teeth 

 being frequently stained a bright violet hue through its predilection for this piquant diet.* 



A species of boring sponge, allied to Hyiiiciiiacidoii celata, has here, as in European waters, to 

 be included among the enemies of the 03'ster. Its attacks are, however, confined almost exclusively 



* In view of this, it is interesting to remark that Howes has recently drawn attention to the fact {Trans. Liverpool 



Biol. Sac, Vol. VI., p. 124) that the interior of the mouth of this fish is beset by a series of uniformly diffused minute teeth. 



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