Guiding Australian Consumers to Sustainable Seafood Choices - SEAFOOD Ecolabelling: Principles and Practice - page 397

environmentally benign aquaculture systems, the Australian Marine Conservation
Society devised the following rating system:
'Say No' - Open-system, intensive aquaculture types with feed added, e.g. seacage
fish farming;
'Think Twice' - Closed and semi-closed system intensive fish (e.g. tank- or pond-
reared barramundi) and coastal prawn farming, with feed added;
'Better Choice' - Open-system aquaculture types with no feed added, e.g. oyster
racks, mussel lines; and small-scale pond and tank invertebrate farming with feed
added, e.g. crayfish ponds.
Species grown in seacage aquaculture fish pens were categorised in the 'Say No'
section of the Guide. This was a policy decision made by the Australian Marine
Conservation Society due to an extensive list of concerns about seacage aquaculture
production systems. Concerns include the potential for such aquaculture systems
to introduce disease to wild fish populations; the high risk of escapes of captive
animals and their potential impact on marine ecosystems; the potential to establish
self-sustaining populations, the nutrient loading to marine systems, and the sourcing
of feed from wild fisheries (thus adding pressure to wild fisheries); and unacceptably
low food conversion ratios.
Growing carnivorous finfish in ponds and tanks where feed is added does not
resolve the issue about sourcing of fishmeal from wild fisheries or unacceptable
food conversion ratios. However, many other environmental concerns such as waste
and escapes can be managed through the closed-system nature of these operations.
The Australian Marine Conservation Society therefore considers closed-system
aquaculture more appropriate than seacage fish farming and thus species from
closed-system operations are categorised as 'Think Twice' - of some concern but
with issues that are resolvable.
Domestic prawn species grown in coastal prawn farms, where feed is added,
have also been categorised as 'Think Twice' species. Coastal prawn farms are
mostly closed or semi-closed systems and so most of the environmental concerns
with these operations can technically be managed. However, extensive areas of
subtropical and tropical coastline in Australia have been cleared for prawn farming
in the past and this is of concern and is emphasised in the Guide. Land clearing for
new prawn farms continues in parts of north-western Australia where governments
and industry have not apparently learnt from the mistakes of the past, and in the
future editions of the Guide these operations would be considered less acceptable
than the existing operations.
Species such as oysters and mussels which are grown in open-system aquacul-
ture arrangements, where no feed is added, or invertebrates grown in small-scale
pond or tank aquaculture have been categorised in the 'Better Choice' section. The
Guide emphasises that the assessment is sensitive to the scale of the operation and