9 



only regained their former position, but eclipsed previous years in productiveness. The accompanying 



figures, derived from the French statistii'al returns, abundantly substantiate this stateratnt. In the year 



1873 the official value of the oyster produce of France was estimated at 2,147,565 francs, or roughly 



£99,000. For the three succeeding years the produce and value of the same fisheries are given as 



follows : — 



Oysters taken oflf beds. Value in I'raucs. English equivalent. 



1874 ... 104,731,350 ... 7,727,000 ... £309,080 



1875 ... 227,640,212 ... 11,247,416 ... £449,896 



1876 ... 335,774,070 ... 13,226,296 ... £529,051. 



lu the year 1887, representing the latest statistics immediately available, the total number of oysters 

 taken from the French fisheries is quoted at 375,000,000, showing that the magnificent record of the year 

 1876 has been beaten. 



A mong the evidence brought forward in the Sydney letters, with the view of depreciating the efficacy 

 of the French system, and republished in Mr. Fison's report, much stress is laid upon the circum- 

 stance that some twenty years ago the Hon. Thomas Holt, recognising the value and capabilities of that 

 system, undertook, at an expense of some £10,000, though unfortunately without success, the construction 

 of extensive culture ponds, or " claires," at George's River, New South Wales, for the cultivation of 

 oysters on the same principle. The causes that led to the failure reported, however, were not attributable 

 to the system, but to the fact that a species of oyster differing essentially in form, habits, and methods 

 of propagation from the European type was experimented with. Having recently availed myself of the 

 opportunity of inspecting these extensive " claires " constructed by Mr. Holt, I am of the opinion that 

 they are altogether unsuited for the culture of the Queensland and New South Wales commercial oyster, 

 Ostrea glomerata, that was the subject of experiment. On the other hand, they would in all probability 

 prove highly suitable for that special fattening process of Ostrea eJulis, for which atone these 

 claires are utilised in France. Propcjrly constructed, these claires take the form of shallow ponds of from 

 twelve to eighteen inches in depth, aud are so connected by means of sluices with the sea that fresh 

 streams of salt water obtain access to them only at spring tides ; the water throughout the intervening 

 periods remains completely stagnant. It is through the culture of the French oyster under the.se special 

 conditions that that green colouration of the oyster's tissues is acquired that command for it so high a 

 price in the Paris market, such colour being due to the character of its food, which consists almost 

 exclusively of the microscopic plants known as diatoms and the spores of the confervoid algce. This special 

 claire system of oyster culture is in no way suited to the Queensland oyster. 



Oyster culture on the French system, on the other hand, in so far as it consists of providing supple- 

 mentary material or apparatus for the catchment of the redundant supplies of spat is undoubtedly 

 worthy the attention of all oyster growers. Whether this material takes the simplest form of the returned 

 parent shells or cultch, or of tree-branches or fascines, or cemented tiles or boards, the result to be accom- 

 plished is identical, and it resolves itself tea question simply as to which of these can be most economically 

 or profitably employed on the areas under cultivation. In this direction it will be found that different 

 descriptions of oyster ground yield the best results in association with diverse descriptions of collectors. 

 On those beds and banks which are more or less completely submerged, and over which there is a sufficient 

 scour to prevent the accumulation of sediment, old oyster shells or cultch constitute the most convenient 

 and efficient form of spat collector to employ. This material, however, if laid on muddy banks, or where 

 there is an insufficient circulating stream, becomes speedily covered with slime and sediment, and is, in such 

 condition, useless as a spat-trap. The sine qua non of successful oyster spat deposit is the existence of 

 a perfectly clean surface for the embryo oysters to adhere to. On the oyster grounds in English waters, 

 such as Whitstable and Heme Bay, where the natural beds consist mainly of such old shells or cultch, 

 its surface is continually worked over with the dredge with the express object of exposing new and clean 

 shell surfaces for the attachment of the embryo brood. 



The form of collector next demanding attention is that of fascines or faggots, composed of boughs 

 and branches of various sorts of timber trees. This description of collector is essentially fitted for employ- 

 ment on oyster grounds where they can be kept continually floating or submerged below the surface of the 

 water. The drawback to the use of fascines, or tree branches in any form, is their liability, on exposure 

 to light, to become speedily coated with slimy growths that leave no foothold for the young oysters. 

 Considerable differences are, however, manifested by distinct kinds of trees with reference to their 

 attraction for oyster spat. The commoner Australian gums, Eucalypti, and wattles. Acacias, are apparently 

 distasteful on account of the puiigencyof the essential oils and essences they continue to exude even after 

 prolonged submersion, and are but rarely encrusted with oyster brood. The Coniferoe, including the cedars 

 and cypress-pines and also the shea-oaks, Casuarinas, have, on the other hand, been found in practice to 

 yield more favourable results than auy other timber, and more especially in experiments conducted by me 

 relating to the artificial propagation of the Tasmanian oyster. The readiness with which the Queensland 

 species naturally adheres to the large branching aerial roots of the orange mangrove, RhizopTiora mucronata, 

 w iuld seem to indicate that this material would form an excellent one for the systematic construction 

 of fascines. 



To render fascines more efficacious as spat collectors, the boughs of which they are composed are, * 

 as used in Europe, not unfrequently washed over with cement. This modified form of fascines 

 leads to those descriptions of collectors in which cemented surfaces are exclusively employed. The 

 most prominent of these are the cemented tih's first employed by M. Coste, and with the aid of which 

 miles of barren mud flats on the coast of France have been converted into mines of wealth giving 

 employment to thousands of individuals. This description of collectors is eminently adapted, and was 

 originally constructed, for employment on banks or flats that are left uncovered at ebb tides, and is 

 unsuited for manipulation beneath the water. 



The peculiar advantages of cemented tiles and of all forms of collectors constructed on the same 

 principle, consist in the fact that the relatively large cemented superficies, being on the under surface of 

 the collector, when placed in position, it remains almost permanently clean and ready for the adhesion 

 of the spat. They are consequently well adapted for employment on mud flats, where there is much sedi- 

 mentary deposit and under conditions in which other forms of collectors would be useless. 



The " split-paling" collectors, first introduced by myself in the Colony of Tasmania, as the nearest 

 approximate substitute for tiles, which were unprocurable, except at prohibitory prices, proved in all 

 ways equal to tiles as spat collectors, and in various directions possessed distinct advantages. Their price 



of 



