The data is the quantitative abundance of megafaunal invertebrates derived from underwater visual census methods involving
transect counts at rocky reef sites around Tasmania. This data forms part of a larger dataset that also surveyed fish abundance
and algal cover for the area. The aggregated dataset allows examination of changes in Tasmanian shallow reef floral and
faunal communities over a decadal scale - initial surveys were conducted in 1992-1995, and again at the same sites in 2006-2007.
There are plans for ongoing surveys.
An additional component was added in the latter study - a boat ramp study looking at the proximity of boat ramps and their
effects of fishing. We analysed underwater visual census data on fishes and macroinvertebrates (abalone and rock lobsters)
at 133 shallow rocky reef sites around Tasmania that ranged from 0.6 - 131 km from the nearest boat ramp. These sites were
not all the same as those used for the comparison of 1994 and 2006 reef communities. The subset of 133 sites examined in
this component consisted of only those sites that were characterized by the two major algal (kelp) types (laminarian or
fucoid dominated). Sites with atypical algal assemblages were omitted from the 196 sites surveyed in 2006.
This study aimed to examine reef community data for changes at the community level, changes in species richness and introduced
species populations, and changes that may have resulted from ocean warming and fishing.
The methods are described in detail in Edgar and Barrett (1997). Primarily the data are derived from transects at 5 m depth
and/or 10 m depth at each site surveyed. The underwater visual census (UVC) methodology used to survey rocky reef communities
was designed to maximise detection of (i) changes in population numbers and size-structure (ii) cascading ecosystem effects
associated with disturbances such as fishing, (iii) long term change and variability in reef assemblages.
Description of biogeographical patterns on an Australia wide scale, for understanding natural variability over time, detecting
changes associated with climate change (range extensions), quantifying impacts of introduced species (e.g. Undaria); understanding
and describing ecosystem effects of fishing, and describing the influence of reef based fisheries at the decade scale.
The initial survey provided a detailed census of marine life for each site, and by re-examining these sites the aim is
to enhance our understanding of how reef species vary over a 12-13 year time scale.
These data will allow better management of rocky reef resources from increased knowledge of changes in these systems through
natural and human induced events, such as introduced species outbreaks, increased fishing pressure, climate change and disturbance
of marine health.
Edgar, GJ, Barrett, NS, (1997). Short term monitoring of biotic change in Tasmanian marine reserves, Journal of Experimental
Marine Biology and Ecology, 213: 261-279.
Edgar GJ, Moverley J, Barrett NS, Peters D, Reed C (1997). The conservation-related benefits of a systematic marine biological
sampling programme: the Tasmanian reef bioregionalisation as a case study. Biological Conservation 79: 227-240.
Stuart-Smith, RD, Barrett, NS, Crawford, C, Edgar, GJ, Frusher, SD. (2008). Condition of rocky reef communities: A key marine
habitat around Tasmania. NRM/NHT Report, Tasmanian Aquaculture and Fisheries Institute, Hobart.
Stuart-Smith, RD and Barrett, NS and Crawford, C and Frusher, SD and Stevenson, DG and Edgar, GJ, ‘Spatial patterns in impacts
of fishing on temperate rocky reefs: Are fish abundance and mean size related to proximity to fisher access points?’, Journal
of Experimental Marine Biology and Ecology, 365 (2) pp. 116 - 125. ISSN 0022-0981 (2008)
Stuart-Smith, RD and Barrett, NS and Stevenson, DG and Edgar, GJ, ‘Stability in temperate reef communities over a decadal
time scale despite concurrent ocean warming’, Global Change Biology, 16 (1) pp. 122-134. ISSN 1365-2486 (2010)
The underwater visual census (UVC) methodology used to survey rocky reef communities involved quantitative diver-based surveys
of fishes, large mobile invertebrates and macroalgae (see below for more detail; also described by Edgar & Barrett, 1997
and Edgar et al., 1997).
A total of 136 sites from 8 bioregions around Tasmania were surveyed in both 1992-1995 and 2006-2007. An additional 60 sites
were either resurveyed (from sites first surveyed in 1999) or surveyed for the first time in 2006.
At each site, 4 x 50m transects were laid at the 5m or 10m depth contour, and fishes, invertebrates (> 2.5 cm) and algae
were recorded separately by a team of 2 - 3 divers. Details of each site, including the date and GPS location, were recorded
and are available at IMAS. The methods below describe the specific survey technique for measuring macroinvertebrate abundance:
MACROINVERTEBRATES:-A diver searched the seabed for a 1 m wide lane along the transect line for cryptic fishes and macroinvertebrates
(i.e. 50 m x 1 m). Four 1 m x 50 m transects were surveyed at each site. Algae were swept away from the transect to obtain
a clear view of the substratum. Mobile invertebrates (including rock lobsters, abalone, sea urchins, octopus etc) were counted,
as were cryptic fishes (also estimated for size). The maximum shell length of abalone and the carapace length of rock lobsters
were measured underwater using vernier callipers whenever possible.
For the boat ramp component, the UVC methods described above were used to record abundance and size structure of fishes
and mobile benthic macroinvertebrates at 133 shallow reef sites around the Tasmanian coastline.