Figure 8. Fragile stony coral and rich biodiversity on a 
seamount at 1,100 m depth 
Video surveys frequently provide valuable knowledge about the 
existence of rare fauna or unknown habitat associations. For 
example, a survey in 1994 identified aggregations of a stalked 
crinoid at 200 m depth in a single submarine canyon off SE 
Australia (figure 9). Crinoids have been in the fossil record of 
the Earth for millions of years but are now relatively rare; this 
is the only known aggregation in temperate Australian waters. 
Recording the presence of crinoids was of value to conservation 
planning, but estimating its density and abundance using stereo 
video will permit the persistence of this remnant population to 
be monitored into the future. 
Figure 10. South-east Commonwealth Marine Reserves (DEWR, 
2007). 
For example, quantitative photographic mapping of the 
distribution of the iconic giant crab off SE Australia revealed 
that a dominant component of the adult habitat is made up by 
low-relief, bryozoan-based ‘thickets’ (figure 11). This habitat 
has a limited distribution on the outer continental shelf and 
upper continental slope (150 to 350 m depths) where bottom 
fish-trawling and giant crab trap fisheries overlap (Williams et 
al„ 2007). 
Figure 9. The rare stalked crinoid Metacrinus cyaneus at 200 m 
water depth. 
In Australia, information from still and video images has been 
used to underpin risk assessment for regulating different 
activities within specific sub-areas of Marine Protected Areas 
and for evaluating the effects of fishing on benthic habitat. 
Figure 10 depicts the first temperate deep sea network of 
marine reserves in the world, the South-east Commonwealth 
Marine Reserve network (DEWR, 2007). The potential impacts 
from a range of different fishing gears was assessed by an 
expert panel of scientists and commercial fishers using 
catalogues of benthic habitat images (Williams et al., 2005) 
which relied heavily on the data produced by the towed body 
system described here. 
While qualitative image data may be used to estimate the 
vulnerability of habitat types, and to record the presence or 
absence of direct impacts, it will frequently be necessary to 
have quantitative data to determine the source and seriousness 
of impacts. Whether impacts have natural or anthropogenic 
causes will determine if mitigation is possible, and quantifying 
Figure 11. A giant crab Pseudocarcinus gigas amongst sponges 
and bryozoans at 340 m. 
Video sequences are now being used to identify and measure 
the sources of visible impacts on this habitat, for example marks 
left by fishing gears (figure 12), and the extent of habitat 
degradation, such as overturned boulders, per swept area of 
video transect. 
m&m 
mmmm 
Hiwfi SB# 
Figure 12. Direct impact of fishing gears: degradation of low- 
relief benthic communities at 132 m depth. 
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