Marine Produce Australia: Cone Bay Barramundi Aquaculture ...

Version Author Authority Comment MPA response
Rev0
Rev0
Oceanica
Oceanica
OEPA
OEPA
(Written)
Comments received from OEPA 1/4/2011
MPA response
The timing of water and sediment sampling was considered in the context of long
term data collected over a four year period. The intention was to undertake sampling
when background nutrient levels were at their annual minimum, thus increasing the
sensitivity of the EQG triggers. This approach is underpinned by statistical theory.
For example, the sensitivity of any statistical test, particularly those looking to detect
anthropogenic effects (if the effects exists), will be maximised when background
concentrations are lowest. In statistical terms, this approach is analogous to
increasing the ‘power’ of the monitoring program. A similar approach has been
adopted in the Environmental Quality Criteria Reference Document for Cockburn
Sound (EPA 2005), where the EQG are defined in terms of the ‘non-river flow
period−when river and estuarine flows are weak’.
The EMMP was developed specifically to determine whether the EQOs have been met.
Further, there is no requirement in the Ministerial Statement that the EMMP must
determine relationships/correlations between data sets−this is an exercise suited
more to scientific research than it is to compliance monitoring. It also stands that
sediments are long term indicators and as such, are unlikely to change quickly in
response to changes in water quality parameters.
Although there is potential for cyclones to disrupt/delay wet season monitoring,
cyclone events are of such scale that all sites (impact and reference) will be affected
equally. It is hence unlikely that sampling, if conducted in the weeks following the
event, would be confounded by such events.
Agreed changes to the EMMP
OEPA and MPA agreed to the following compromise: Both sediment and water quality
monitoring will be conducted over a four month period (July-October) during the
winter dry season. The timing of sampling will allow monitoring to proceed when
weather conditions are stable, and when background water quality concentrations of
chlorophyll and nitrogen are lowest. The frequency and timing of monitoring will be
reviewed 3 years following implementation of the EMMP.
MPA response
Additional reference sites were provided to capture the water quality gradient
between the eastern and western ends of Cone Bay, and to overcome issues with the
inappropriate positioning of existing reference sites (i.e. Cone Bay SW entrance). The
additional reference sites included in the EMMP are expected to capture the range of
water quality conditions in Cone Bay, while also being beyond the influence of the
existing aquaculture operation (i.e. sites ER1-ER3 are 1.2 to 1.9 km from the nearest
sea cages). It is important that the full range of water quality is captured so as to
allow for a fair comparison of medians with higher percentiles.
Oceanica’s understanding is that all of the additional reference sites are located well
inside the Maximum Ecological Protection area, so on this basis alone, should not be
affected by the barramundi aquaculture i.e. the criteria for the Maximum Ecological
Protection Area there are to be no changes from the normal distribution.
Agreed changes to the EMMP
OEPA and MPA agreed to the following compromise: Reference sites located at the
eastern end of the aquaculture lease are to be retained in their present locations.
This is to ensure they capture the possible confounding effects of Snapper Cove,
which is known to contribute significant levels of nutrients to Cone Bay during tidal
exchanges, and following rainfall events. Reference sites located at the western end
of the aquaculture lease are to be moved north west of their present location. This is
to account for the fact that modelling was not undertaken for conditions at the
western end of Cone Bay; it is therefore not certain whether the Reference sites at