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Abstract

The reef biota in four Tasmanian marine reserves and at associated unprotected reference sites
was investigated over a 6-year period following protection from fishing. The largest reserve at
Maria Island (7 km coastline length) proved the most effective at achieving species conservation
and resource enhancement. The number of fish, invertebrate and algal species, the densities of
large fishes (.325 mm length), bastard trumpeter (Latridopsis forsteri ) and rock lobsters (Jasus
edwardsii), and the mean size of blue-throated wrasse (Notolabrus tetricus) and abalone (Haliotis
rubra), all increased significantly within the Maria Island reserve relative to external reference
sites. Increases of an order of magnitude in the biomass of rock lobsters and two orders of
magnitude in the abundance of trumpeter were particularly noticeable. Small abalone declined in
density within the reserve, while large abalone became more numerous. The effectiveness of
marine reserves corresponded with reserve size. Changes in species richness of fishes, invertebrates
or plants were not detected in any of the three smaller reserves, other than an increase in
number of fish species greater than 325 mm size within the Tinderbox marine reserve (2 km
reserve length). Although patterns were partly obscured by the low power of statistical tests, trends
were generally evident at the Tinderbox reserve for increasing densities of large fishes and rock
lobsters, and for increases in the mean size of rock lobsters, abalone and blue-throated wrasse.
Most of these trends were not apparent in the reserves with small reef areas at Governor Island (1
km reserve length) and Ninepin Point (1 km length). Rock lobsters above the legal size limit
nevertheless became abundant in all reserves by the end of the study while remaining rare outside.
Indirect changes to reef assemblages were also detected following the declaration of the Maria
Island marine reserve. Accompanying the increase in macroalgal species richness was a change in
predominant plant species from Cystophora retroflexa to Ecklonia radiata. Results of this study
provide the first clear evidence that shallow Tasmanian reef ecosystems are overfished, and that
unfished coastal ecosystems differ substantially from those where fishing occurs. The most noticeable changes caused by fishing were the virtual elimination of net-susceptible and heavily
targeted species, which may otherwise be common, plus indirect changes to algal communities.We
suggest that ecosystem change associated with fishing of shallow coastal reefs may be a
widespread phenomenon worldwide.

Item Type:	Article
Authors/Creators:	Edgar, GJ and Barrett, NS
Journal or Publication Title:	Journal of Experimental Marine Biology and Ecology
ISSN:	0022-0981
DOI / ID Number:	https://doi.org/10.1016/S0022-0981(99)00098-2
Additional Information:	The definitive version is available at http://www.sciencedirect.com
Item Statistics:	View statistics for this item

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