392 
THE TROPICAL 
AGRICULTUiaST. 
[Dec. ], 1900. 
The Liiigas on the shc-lf were similar in every 
respect to the Gulf of Mannar oysters. 
1 have recently seen in print that the annual 
value of the Persian Gulf Peai l Fishery is £300,000. 
On niy return to Ce;ylon I obtained the sanction 
of Governniont to send home a rrial shipment of 
pearl oyster shells, and in December, 1876, ihesliells 
of 12,000 oysters that had been lifted for a sample 
of pearls for the fishery of the following years were 
sent to the Crown Assents to dispose of, in communi- 
cation with Messrs. ijtooks & Faith, but subse- 
quently they reported that the shells were of no 
value. 
However, the Gulf of Mannar Pearl Oyster shell 
must now be of some value, as durini; the recent 
fisheries men were sent by mercantile firms in 
Colombo to collect shells for shipment to Europ 
MIGRATION OF OYSTERS AND EMPLOYMENT 
OP DIVERS WITH DIVING DRESS. 
It has frequently been surmised when oysters 
were reported to have disappeared from a bed 
and no traces left of them, tluit they had jirobably 
migrated to some other more suitable locality, 
into depths beyond the capacity of native divers 
to reach ; and that the employment of European 
divers with diviiif; dress might be the means of 
tracing them, or of finding new beds of oysters. 
My experience of pearl oysters is that they only 
move about in their young stage, say up to one 
year old, and after that age they remain on the 
bed they settle down u;ion, if a rocky bed, until 
they come to ripe old age, unless they are forcibly 
removed ; but if they happen to come on a sandy 
bed, they would have no means of holding on, and 
would most probably be drifted away and des- 
troyed. 
I am led to this conclusion, by observing that 
it is only during their j'oung stage that I find, 
when at anchor on a bed of oysters, that they 
attach themselves to the vessel's cable. The fact of 
the oysters mooring themselves by such a strong 
cable as they do, would also bear out this conclusion, 
for if they were in the habit of moving about 
always, it would be unnatural for them to moor 
with many threals of th,eir byssus, when one or 
two threads would be sufficient for a temporary 
resting-place. But supposing they were in the 
iiabit of migrating and got into depths beyond 
the capacity of the native diver, say 10 fathoms 
as his greatest working depth, the coiiHguration of 
the bed of the ocean, in the neigliboui hood of the 
Pearl Banks is such, that a short distance would 
take them into deoihs beyond the capacity of 
even the diver with diving dress, ag' the edge of 
the bank of soundings is very precipitous. 
It has often been suggested also, that better 
results would be obtained on the pearl banks by 
the employment of divers with diving dress, both 
at inspections of banks, and at fislieries ; but as a 
matter of fact, I have had ex])erience of the diver 
with diving dress in both these cases. 
Some years ago a Eurojiean diver was employed 
regularly at inspections of the banks, and in Apiil, 
1884, I had four European divers along with native 
divers, employed in the fishing of a bank of oysters 
^ Chilaw ; when [ found the native divers brought 
up in a day's work as many oysters per diver as the 
Euro))ean divers. 
At inspections of the banks, it is necessary to 
get over the ground quickly, as there are very 
large aresis to be examined, and the native diver, 
who can be taken about in a handy rowing boat, 
making a dive when wanted, during which he goes 
over a space of about 20 square yards, and brings 
up a .sample of what is on the bottom, over that 
area, all in about one minute, is just the man 
required. I have never known any of the native 
divers employed at inspections to" give a false 
report of the state of the bottom, a>id I have 
found that I could form a far better idea of (he 
state of a bank from their reports, than I could 
from that of the European diver, who could not 
move about as quickly as ti.e native. 
In this connection I will relate an amusing incident 
that occurred during the fishery oH Chilaw in April, 
1884. One morning tlie European divers reported 
to me that there were no oysteis where the 
vessel was anchored, and ked for it to be moved 
to another part of the bank. I knew from the 
native diver's report that the vessel was anchored 
on the best part of the bank, so I called np four 
native boats, an<l told t'le tindals to work close 
round the siiips, which they did, and their native 
divers sent up oysters, 50 to a dive. (Jn seein}; 
this the European dive)'s began work ag'.in, and 
found oysters. Some time after they had been 
working, I was looking over tlie vessel's side, 
and observing the' life line of one of the Europeaj'i 
divers being violently jerked, I called out to his 
attendants to haul him up quickly, believing 
that some accident had happened, and that the 
poor niau might be hauled in unconscious or even 
dead, but when landed on the stage, he was 
very much alive, for when the front piece of hi.s 
helmet was removed, he bawled out in a stentorian 
voice " Where's the man who stole my oysters." 
He then explained that he had kept a basket 
at t!;e foot of his ladder to hold the oysters 
as he gathered them up, and that when he 
returned to the Ijasket with the last handful of 
oysters required xo lill it, he found the basket 
empty and oysters gone, and that his rage at 
this mishap caused him to tug so violently at 
the life line. The oysters hail been commandeered 
by one of the native divers (belonging to one of 
the boats working close by), while the European 
diver was aw:"y from his basket. 
This I found out some time afterwards, but 
as thpre was no evidence available at the time, 
the ihief escapedpunishment, much to the annoy- 
anc of the European diver 
PHYSICAL CHANGES IN THE BED OF THE 
SEA ON THE PEARL BANKS. 
As far back as my exjierience goes, there have 
l)een no material changes of this nature. It is 
true the divers have at times reported small 
portions of the rocky part of a pearl oyster bed 
to be covered with a layer of sand a few inches 
deep, and on one occasion during a small fishery 
off Chilaw, the divpi.s reported, the oysters were 
being covered up with sand ; and that they had 
a difficulty in getting at the oysters as they were 
swayed to and fro by the sea. although they were 
at a depth of 9 fathoms. This was evidently 
caused by a heavy ground swell rolling in at 
the time, and if it swayed the divers about, was 
also probably causing the silting up of sand on 
the oysters. These occurrences are, however, lare, 
or have been rarely norieed. The bed of the 
Cheval and Modrigam Paars seem to remain 
undisturbed by physical changes, as the area and 
eonliguration of their rocky portions have been 
fairly maintained during my time. No silting 
up or upheaval in their neighbourhood can be 
detected by the soundings, which have not de- 
creased during the last seventy years. Changes, 
however, are taking place on the shore in tliat 
