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How to Use the AQUAmark
The AQUAmark is designed to be attached to fishing gear at
regular intervals, typically on a head rope for bottom set
nets, or on a foot rope for drift nets. It should not be
allowed to rest on the seabed or be buoyed into the swell
, as this will mask the sound. The device includes an eye
to allow it to be attached using rope. It can also be braided,
possibly with additional flotation (see right), to minimise
any risk of snagging. Some fishermen have also used bait
bags as a convenient method of fixing.
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To ensure adequate
acoustic coverage for porpoise deterrence, the AQUAmark
100 should be attached to the ends of the gear, and at
separations not exceeding 200 metres. This spacing has
also been found acceptable for the AQUAmark 200 where dolphin
bycatch is a problem, although closer spacing may be necessary
when there is deliberate predation from fishing gear. The US
NMFS regulations specify a 300ft maximum spacing for pingers
such as the AQUAmark 300.
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Maintenance and Testing
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The AQUAmark is virtually maintenance free. It contains a
built-in battery that is sealed in. The typical life in a
seasonal fishery, where nets are also taken out of the water
during the fishing season, can approach the stated battery
shelf life of 4 years. This is because the device includes
a contactless immersion switch that senses complete immersion.
Even when the devices are wet, but out of the water, the
switch will detect this and turn off the pinger.
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Out of season, the devices should be rinsed in fresh water and placed in a
dry environment. If they can be stored at normal room temperature,
this will improve battery life. Battery life will not
deteriorate out of season unless they are left in a cold
outdoor environment, or in direct sunlight.
Operational integrity is verifiable by periodic testing.
For those with good hearing, the AQUAmark 200 and 300 are audible.
All pingers emit a coded signal incorporating serial number and battery
level when they first switch on after immersion. A trained ear
can count the battery transmissions (5=Full to 1=Empty battery).
Alternatively, easy to use testers are available (see right).
These are essential for the AQUAmark 100, whose ultrasonic
transmissions are generally inaudible. They provide audible
and visual indication of correct function.
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