Marine Produce Australia: Cone Bay Barramundi Aquaculture ...

� Where sites are inferred to be in the MEPA and the HEPA, as in the above example,
medians should not be calculated if the number of sites is less than n=3 (as a minimum of
three samples is required to derive a meaningful estimate). In this case, additional
samples shall be obtained such that the number of measurements is at least n=3 (see
also footnote #15).
Median DO values will be compared to the EQG calculated from n=8 Reference Sites. EQG,
encompassing the 80th and 90th percentiles shall be calculated after each sampling occasion.
After completion of the four month sampling period
At the completion of the four month sampling period, ammonia and DO values obtained at
each of the HEPA and MaxEPA sites over the four sampling occasions will be pooled and the
sample percentiles calculated. For example, the median for high protection site 1 (H1) will be
calculated by pooling data obtained on sampling occasions 1, 2, 3 and 4..
Similarly, at the completion of each sampling occasion, ammonia and DO values obtained in
the MEPA, or any gradient site located outside of the MEPA, will also be pooled and the
sample median calculated: Where sea-cages are located greater than 200 m from the
western MEPA/HEPA boundary (such that all sites are positioned in the MEPA, irrespective of
current direction), medians will be calculated by pooling data obtained on occasions 1, 2, 3
and 4, and compared against the EQG for moderate protection. However, where sea-cages
are located less than (or equal to) 200 m from the western MEPA/HEPA boundary (meaning
some or all of the sites are inferred to be in the HEPA), the EQG will be assessed differently
depending on the inferred position of the sites. For example, if a site falls outside the MEPA,
then the EQG for high protection will be used, and if the site falls within the MEPA, then the
EQG for moderate protection will be used. This approach is summarised in Figure 5.1.
For sites positioned at the HEPA and MaxEPA boundaries, sample percentiles will be
calculated for each of the replicate sites (n=4): H1-H4 and Max1-Max4, respectively. Median
DO values will be compared to the relevant EQG calculated from pooled Reference Site data
(n=4x8=32) obtained over the four month sampling period.
In the event the EQG for ammonia is exceeded, spare samples collected on the same day as
the original samples will be analysed. If the EQG is still exceeded following reanalyses, then
monitoring shall be undertaken against the relevant EQS as soon as reasonably practicable.
5.1.3 Chlorophyll-a
Sample medians will be calculated after each sampling occasion. Chlorophyll-a values
obtained from the sites at the boundary of the HEPA will be pooled and the sample median
calculated (n=4). In this case, the sample median will be compared against the EQF for high
protection (80th percentile). Identical methods will be employed in the case of the MaxEPA:
Chlorophyll-a values obtained from the sites at the boundary of the MaxEPA will be pooled
and the sample median calculated (n=4). In this case, the sample median will be compared
against the EQF for maximum protection (70th percentile).
These data will be compared to the EQG calculated from n=8 Reference Sites. EQG should
be calculated after each sampling occasion. In the event the EQG is exceeded, spare
samples collected on the same day as the original samples will be analysed. If the EQG is
still exceeded following reanalyses, then monitoring shall be undertaken against the relevant
EQS as soon as reasonably practicable.
5.1.4 Sediment quality
Sample percentiles (median and 95th) will be calculated twice: once, after each sampling
occasion and then again, following the completion of the four month sampling period.
After each sampling occasion
At the completion of each sampling occasion, TKN, TP, TOC and redox discontinuity values
obtained at the HEPA and MaxEPA boundaries respectively will be pooled and the sample
median calculated (n=4). Similarly, at the completion of each sampling occasion, TKN, TP,
TOC and redox discontinuity values obtained at gradient sites will also be pooled and the
Oceanica: Marine Produce Australia: Cone Bay Barramundi Aquaculture, Environmental Monitoring & Management Plan 39