Marine Produce Australia: Cone Bay Barramundi Aquaculture ...

To calculate the Inverse Simpson Index, the species richness of impact sites will be compared
to the sediment quality Reference Sites. The Inverse Simpson Index is ideally suited as an
EQS, as its sensitivity can be configured for either minor or moderate level impacts.
5.2.2 Assessment of imagery
Visual assessment of sediment condition beneath sea-cages is a rapid and simple method for
quantifying unacceptable levels of change. For example, sea-cages in Tasmania are fallowed
as soon as practicable following observation of hydrogen sulphide bubbles (Crawford 2003).
However, such indicators are generally representative of moderate to severe levels of change
(Crawford 2003), and are not suitable for application outside the MEPA.
Upon exceedance of an EQG, MPA will undertake photographic surveys as soon as reasonably
practicable. If the exceedance relates to the EQG for moderate protection, surveys will be
conducted beneath the sea-cages. Images will be recorded and saved to a hard drive. The
images will then be assessed qualitatively to determine whether there have been changes in
key indicators. For the moderate protection area, these include: white bacterial mats, MPBs,
black sediments, bubbles of hydrogen sulphide, mass mortality of benthic macrofauna, or a
significant reduction in the presence of animal tracks and/or bioturbator burrows, relative to
reference sites.
If the exceedance relates to the EQG for high/maximum protection, photographic surveys will
be undertaken as follows: at coral sites on an exceedance of the EQG for TSS, LAC and
phytoplankton biomass. Photographic images will be analysed qualitatively for the presence
of coral mucous, and/or a reduction in coral pigmentation.
5.2.3 LAC and TSS (LOI)
As per the multiple lines of evidence approach outlined in EPA (2005), EQS have been
developed for TSS (LOI), and LAC. The intent is to use these indicators in conjunction with
the indicators of coral health.
Upon an exceedance of the EQG for TSS (LOI), LAC or phytoplankton biomass, sampling at
each of the coral monitoring sites will commence as soon as reasonably practicable. The
intent is to establish whether measures of TSS and/or LAC at the coral impact sites are
beyond the range recorded naturally, as determined by ANOVA. Sampling will continue at
the impact and reference sites two times per week over an eight week period, resulting in a
sample size of n=16. Sampling will be timed to coincide with outgoing tides when coral
impact sites are more likely to receive inputs from the sea-cages.
5.3 Monitoring-management feedback loop
The order of events following an exceedance of either the EQG or EQS for water and
sediment quality is provided in Figure 5.2 and Figure 5.3, respectively.
Oceanica: Marine Produce Australia: Cone Bay Barramundi Aquaculture, Environmental Monitoring & Management Plan 41