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substantial number of ships have been deratted by "1080" in preference to the use of cyanide
resulting in a considerable saving of time and cost to the ship owner.
(d) Trapping. This method is seldom used except as an expedient to eliminate isolated rats
and/or to secure specimens for the laboratory.
(e) Methyl Bromide. This is a very effective and lethal fumigant which has been used over
a number of years in the Port as an insecticide, particularly in the dried fruit industry. It
has considerable penetration powers and is not difficult to disperse after an operation. It
is also possible to use this gas as a rodenticide and where there is an infestation of
rodents and insects the combined problem can be solved with one operation.
The following are the names of the firms approved for carrying out the deratting of ships:—
London Fumigation Co. Ltd.
Contra-Pest Service Ltd.
Rentokil Laboratories Ltd.
(iv) Progress in the Rat Proofing of Ships
No Change.
RODENT CONTROL MEASURES CARRIED OUT ON LIGHTERS
In recent years there has been a steady decline in the number of lighters found to be infested
with rats. The factors which have led to this decrease are as follows:—
1. Cleanliness and Hygiene
Freedom from rats depends, in a large measure, upon proper maintenance and cleanliness of
the lighter itself. A lighter should be systematically cleaned at frequent periods. Each time a
hold is emptied, the dunnage or gratings should be stacked and the hold swept clean before the
dunnage or gratings are laid again.
2. Harbourage
This is divided into three types or classes - structural, incidental and temporary.
Structural harbourage is that type which is integral with the lighter's structure. Incidental
harbourage is that type located in or around equipment placed within the lighter. Temporary
harbourage is that type existing in movable supplies, stores, dunnage etc. In other words, structural
harbourage results from design and construction and is built into the lighter; incidental
harbourage is introduced aboard the lighter and temporary harbourage results from the manner in
which the lighter is operated.
3. Ral-prooling
Rat-proofing includes the abolition of harbouring and nesting places, the isolation of the rat
from a food supply and the prevention of rat communications between compartments.
Rat-proofing may be accomplished in two ways — by protection, or by elimination, of partially
or totally enclosed spaces. Protective methods apply generally to the rat-proofing of existing
lighters which have numerous spaces available for rat harbourage and which can be protected
from infestation only by making them rat-proof. Rat-proofing by elimination of enclosed spaces
is applicable in the design and construction of new lighters. It is by far the most scientific and
satisfactory method. The adoption and observance by the Lighterage Industry of the Port Health
Authority recommendations relating to the rat proofing of lighters has, since its introduction in
1959, played a very important part in containing the rodent population to a minimal level.
The methods of deratting employed throughout the year were:-
Fumigants Rodenticides
1. Sulphur Dioxide Sodium-fluoroacetate (1080)
2. Methyl Bromide
The method of treatment is determined by the condition and degree of infestation at the time
of inspection.
During the year, fourteen of the rats recovered from treated lighters were sent to the Public
Health Laboratory, County Hall for routine bacteriological examination. Pasteurella pestiswasi
not isolated from any specimen.
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