THE TROPICAL 
AGRICULTURIST. [April ], 1904. 
CEYLOIS' PEAEL FISHERIES. 
PKOFESSOK HERDMAN'S REPORT AND 
RECOMMENDATIONS. 
The fact that the receipts of the Peavl 
Fishery of 1904 for the first eleven days 
amount to within E4,000 of half a-milliun 
rupees, whereas last year the taiiings for 
the same period of eleven days (March 3rd 
to 13th) was little more than one-third of 
this— K187,878, lends an added interest to the 
first sessional paper of 1804 : Summary of 
of Dr. Herdman's Report to the Ceylon Gov- 
ernment oa the Pearl Oyster Fisheries of the 
the Gulf of Manaar. The Professor's im- 
portant recommendations we have quoted 
in full elsewhere. The remainder of this 
summarised report, which it is most satis- 
factory to have at once, in view of the 
great size and highly scientific nature of tbe 
more elaborate work to come, IS, however, of 
such interest that our readers will be glad to 
have the bulk of it given following. The suc- 
cessful results of Prof. Herdman's mission 
are evident almost every step of the way. 
The knowledge of the pearl oyster and its 
habits, absolutely as well as with special 
reference to our shores, has been added 
to in no small measure— to the gain of 
science in the world at large. But, with 
special regard to Ceylon, the causes of 
the shifting of oysters from place to place 
have been made more clear ; the safety of 
transport and the benefit to be derived from 
it are emphasized, especially from the results 
obtained at Galle ; and the kind of bed that 
the oysters prefer to lie upon, a very im- 
portant item in the delicate life of this 
mussel and if farming operations are to be 
carried on successfully, has been studied to 
most fruitful purpose. With the portion of 
the report dealing with pearl formation (to 
appear later), we shall have reproduced the 
Summary completely. In that portion the 
advantage of dredging is fully em- 
phasized, numbers of oysters having been 
thereby found on places not known as 
" paars." The Recommendations urge the 
substitution of dredging for diving "either 
wholly on in part " ; and no doubt the cost 
of dredging will be carefully compared at 
the present fishery with that of diving 
(allowing for the oysters paid to the boat- 
men) and the future method— or methods— 
duly settled. By the artificial " culching" of 
sandy bottoms, proposed, near important 
paars, large areas may be brought under 
pearl oyster cultivation that will make the 
" pearl " revenue of the Colony a permament 
yearly section amounting to about one 
million rupees, at least. We understand that 
the present fishery is likely to last till April 
20th ; one-tenth of the yield generally covers 
expenses. The chief duty of the Marine 
Biologist (now Mr. Hornell), is, in fact, laid 
down as the farming of the oysters-banks 
in such a way as to ensure a constant sup 
ply of mature oysters; how far this will 
succeed, remains to be seen. But so exhaus 
tive have been the experiments, and so 
fully drawn up are the scientific conclusions, 
that we feel assured that success is in 
store and that the fame and lustre of 
Dr. Herdman's splendid work, in which 
Mr. Hornell has had so distinguished 
a share, will only become greater and more 
brilliant as the decades come and go and as 
Governor succeeds Governor in the favoured 
island of Ceylon. 
PEARL OYSSER FISIIDRIER OF THE 
GULE OF MANNAR. 
SUMMAFtY OF RESULTS. 
(Extracts from a Report bii W A. Herd man, Esq., 
D.Sc, F.B.S.) 
As a result of tlse observations and experiments 
given in the preceding pages, or still to be detailed 
in the Special Reports whieli vvill be published by 
the Royal Society, 1 have arrived at certain con- 
clasious upon which the recommendations that 
follow are based. 1 Jo not claim that all these 
conclusions are new. Some are merely corrobo- 
rations and extensions of the discoveries and views 
of ray predecessors ; in other cases we have been 
able to ascertain new facts and so correct former 
opinions, or settle points that were in dispute. I 
believe that we are now in a position to give a 
sufficiently complete and continuous account of the 
life history and habits of the Ceylon pearl oyster 
to serve for practical purposes, and to enable us to 
picture with fair accuracy the details of its life- 
economics, its feeding and breeding, its struggles 
with enemies and competitors, with sand and 
with storms, and fiually its association with 
Cescode p irasites, and the consequent process 
of pearl formation. 
THE CONCLUSIONS 
may be stated briefl7 as follows : — 
The Pearl Oyster, or rather " mussel." of the 
Ceylon fisheries lives in very pure and clear sea 
water in the Gulf of Mannar on certain patches of 
hard ground known as " paars." The Paars are, 
for ihe most part, at depths of 6 to 9 fathoms, and 
those that are best known lie at a considerable 
distance from land, the Cheval Paar at 9 to 14 
miles, the Periya Paar Kerrai at 12 miles, and the 
Modragama at about 3 miles from the nearest 
coast. The Muttuvaratu, at about 4 miles off 
Karativu Island, is the only one where important 
fisheries have been held — that is, near the shore. 
The hard bottom of the paars is to some extent 
formed of corals and shells, but to a much larger 
extent by a modern "rock" no.w forming in si^w. 
This may be called a calcrete," as it is com- 
posed of the sand and neighbouring organic 
remains cemented into a continuous hard muss 
by carbonate of lime. We have shown that 
the cementing, although no doubt in part a chemi- 
cal process, is in places largely due to living 
NuUipores and Polyzoa, especially the latter. 
Where the bottom on the pearl banks is not 
calcrete, it is formed of a coarse sand in some 
parts almost wholly inorganic, with large quartz 
grains, and derived from the waste of the grani- 
toid rocks of central Ceylon brought down by the 
rivers. Elsewhere the sand is of organic origin 
being formed by the shells of large bottom-living 
Foraminifera, such as Heterostegina depressa and 
Orbitolites complanata and of the calcareous 
remains of many other kinds of animals. 
The divers distinguish between a hard bottom 
("paar") suitable for pearl oysters and a sandy 
one which is more or less useless. The sand, how- 
