"تقرير المتحف البريطاني حول الخليج الفارسي كمنطقة محتملة لإنشاء مصائد إسفنج ناجحة (Pol. No. 1718/05)" [و‎‎١] (٤/١)

B. 152 4
British Museum Report on the Persian Gulf as a Possible Area
for Successful Sponge Fisheries. (Pol. No. 1718/05.)
There is no definite information in literature concerning the existence
of commercial sponges in the Persian Gulf; and, although the Natural
History Museum possesses specimens of horny sponges from that region,
some ol which were collected by the writer of this Report in the course
of a voyage from Basra to Karachi, there are among them no typical
commercial sponges. In spite of this negative evidence, which is of small
importance, it is very probable that commercial sponges do exist in great
abundance in certain localities in the Gulf, especially, for instance, on the
extensive pearl oyster beds.
The fact that there has hitherto been no trade in sponges from the Persian
Gulf is no proof against their existence. Previous to 1840 the sponge trade
of the West Indian region did not exist, and its origin at that date was due
to an accident; now thousands of men are employed in the industry.
The Persian Gulf, or "the Green Sea," is a shallow enclosed sea, the
depth of which rarely exceeds 55 fathoms. Numerous islands and shallows
occur in its south-western portion and near the entrance to the Straits of
Ormuz. The bottom is formed of mud, clay, sand, and rocks, the last two
being favourable ground for sponge growth. Outside the Gulf and along
the coast of Muscat, the 10-fathom line extends out several miles from the
shore; and beyond this line the great depths are reached.
Conditions Favourable to the Growth of Commercial Sponges.
These sponges flourish in warm temperate and tropical waters in depths of
from 10 to 30 fathoms, though their bathymetrical range is from 2 to 70
fathoms. They grow best on rocks and reefs in currents of three or four
knots an hour. Too strong currents cause the growth to be irregular.
Z nfavourahJe Conditions that might Prevent Successful Sponge Fishing
in the Persian Gulf.
Mud is obnoxious to most sponges. There is no likelihood of commercial
sponges being abundant in the northern end of the Gulf, where the
diluvium brought by the Shat-el-Arab is being deposited.
The " Shamal," or Dust-wind, a north-west wind that fiils the air for
days together with dust from the plains of Mesopotamia, would probably be
rather detrimental to certain forms of submarine life, for the impalpable
sand and dust foil on to the water, and are partly suspended and partly sink
to the bottom.
Lastly, occasionally the temperature may be too great for healthy sponge
life.
An air temperature of 179° Fahr. has been recorded on the Muscat
coast; this would give rise to a water temperature nearly as high {i.e.,
within 33 lahr. of boiling water) in simHow water of only a few fathoms
depth.
S. 33.