the reef biota at bunurong marine national park - Parks Victoria

Parks Victoria Technical Series No. 84
Bunurong Subtidal Reef Monitoring
3.5 Fishing
Abalone
The average size of blacklip abalone, H. rubra, was similar between the Bunurong MNP and
the reference areas during most surveys prior to 2006, with variations in mean size generally
less than 5 mm length (Figure 3.23a). A marked decrease in mean size of H. rubra was
measured both inside and outside the MNP between 2006 and 2011, with mean size falling
to well below previously observed sizes (Figure 3.23a). The proportion of legal sized abalone
has also declined during this period to lowest observed levels, both inside and outside the
MNP (Figure 3.24). Although a decline was also evident in MNP sites the scale of decline,
and low abundances (Figure 3.23b), suggests an increased in fishing pressure in Western
reference sites, which may extend into the MNP, to a lesser extent.
Rock Lobster
The southern rock lobster J. edwardsii is common inside the MNP, however the survey sites
do not encompass their preferred microhabitat and do therefore do not adequately survey
their abundances (Figure 3.25).
Fishes
The size spectrum analysis indicates that in reference sites the abundance of larger fishes in
2006 and 2010 were amongst the lowest of all surveys, 2010 was also the lowest for sites
within the MNP (Figure 3.26). The biomass and density of fishes above 200 mm length in
2006, 2010 and 2011 is also the lowest of recorded observations inside the MNP. Similarly
observations of biomass and density of fishes above 200 mm length at reference sites were
low in 2010 and 2011 (Figure 3.27 and Figure 3.28). A decline in size of the larger, fished
species, including blue throated wrasse N. tetricus, senator wrasse P. laticlavius and magpie
morwong C. nigripes was apparent (Figure 3.29 to Figure 3.31). Mean size of purple wrasse
N. fucicola was relatively consistent across all surveys, however no N.fucicola were observed
within MNP sites in 2011 (Figure 3.32).
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