SUSTAINABILITY REPORT 2015

Bird Gate Innovation
Bird gates were developed as an on
farm innovation to allow birds to make
their own way out of fish pens if they
were to gain entry. The principle behind
the bird gates is that while there is
enough room for the birds to walk
through the gaps there is no platform for
them to land on the outside, or enough
room for them to fly through.
The gates are clamped onto the fish
pen handrail and the existing bird net
is stitched around the framework of the
gate. There is a support bracket that
sits against the inside of the stanchion
to ensure the gate stays in its required
position. A platform is located on the
inside for birds to land on when they
are in the fish pen and they can walk
through the gap and take off.
The bird gates are very effective for
Silver Gulls, and there have been
instances of a bird leaving the fish pen
within five minutes of the gate being
fitted. Tassal is conducting more trials
on enlarging the exit point enough to let
the larger gull (Pacific and Kelp Gulls)
species exit while not enlarging them
so much that seals see this as an entry
point. The gates are made out of 40 mm
aluminium tubing and weigh around five
kilograms, so they are easy to handle
and mount onto the pen by one person.
Salmon Escapes
There is currently no specific salmonid
escape legislation or regulation in place
in Tasmania. There are, however, a
number of elements in place at Tassal
that provide a management framework.
These include licence conditions
to report significant escapes, and
legislation preventing intentional release
of fish. Tassal is required to report
escape events of more than 500 fish
at any of our marine farming leases,
however we have made the decision to
report on all escape events of more than
100 fish. No Salmon escape events
occurred during the FY2015 reporting
period.
Due to the absence of native salmonid
stocks in Tasmania, ecological
interactions between wild and farmed
Salmon and associated genetic impacts
remain a non-material issue. Tassal
does not rear transgenic fish stocks.
In Tasmania, the potential impacts of
escaped Salmon include:
• Establishment of feral breeding
populations
• Negative ecological impacts on native
fish populations and prey species,
and
• Disease transfer from farmed fish to
native fish.
Tassal has a comprehensive Escape
Prevention and Response Protocol
(EPRP) that has been implemented to
eliminate stock escapes from marine
farms within areas that can be controlled
and to minimise the risk from areas
where it cannot. The EPRP supports the
best practice management requirements
of our ASC certification and the
Macquarie Harbour Area Management
Agreement (MHAMA).
Marine operations staff are trained in
escape response, and escape drills
occur at least annually on each site.
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