Surveys of fish, invertebrates and algae were conducted on subtidal rocky reefs within the Batemans Marine Park (BMP) in December 2005 (11 sites), 2006 (25 sites) and 2007 (22 sites). At the time of the 2005 and 2006 surveys, the BMP had been created but legislation to implement the zoning scheme and hence enforce fishing restrictions was not in place. Data obtained in 2005 and 2006 thus represent
baseline conditions. The zoning came into effect in June, 2007. The BMP surveys form part of a broader study into the effectiveness of marine protected areas (MPAs) in Australian temperate waters. Surveys were undertaken with identical methodology to studies in the nearby Jervis Bay Marine Park (Barrett et al., 2006) as well as in Western Australia, South Australia, Tasmania and Victoria.
Surveys assessed the diversity and abundance of fish and macro-invertebrates and percentage cover estimates of algae and sessile invertebrates. One hundred and nine species of fish, fifty five species of macro-invertebrates and seventy three species of algae were counted throughout the surveys. Schooling fish species such as Chromis hypsilepis (One-spot puller), Atypichthys strigatus (Mado
sweep) and Trachinops taeniatus (Eastern hulafish) were the most abundant at most sites. The most abundant resident reef fish were Parma microlepis (white-ear), Crinodus lophodon (Rock cale) and Notolabrus gymnogenis (Crimson-banded wrasse). The most abundant invertebrates were Centrostephanus rodgersii (Long spine urchin), Astralium spp. (Turban shells), Heliocidaris spp. (common urchins)
and Turbo spp. (Turbo). In many locations C. rodgersii were very abundant and formed extensive barrens. This most probably impacted on algal assemblages, with many sites devoid of canopy forming algae in the depth ranges (5 and 10 m) surveyed. Algae covering most substrata sampled were crustose coralline algae, species of Peyssonnelia (red algae) and Ecklonia radiata (brown kelp).
The survey methodology was designed to detect changes at all levels of species interaction and the response of sanctuary zones to protection. Ideally surveys should be repeated each year, producing a time-series of data documenting changes in the abundance and distribution of species of interest. This would also provide an indication of MPA performance as observed changes between management zones could be differentiated from chance divergence. It would also provide a reference for assessing the extent of fishing related influence on the regions subtidal reef ecosystems. Surveys of fish and mobile invertebrates should be repeated on an annual basis and surveys of algal assemblages be conducted on at least a biannual basis, until biotic changes associated with MPA protection stabilise. Because the sites surveyed in 2005 & 2006 were deliberately different (utilising available resources to maximise sampling coverage of the BMP and sanctuary zones), the large number of sites surveyed overall meant not all could be re-surveyed in the time available in 2007. The 2007 sites therefore represent a random sample of those covered by previous surveys, and as many as could be sampled within the time and logistical constraints imposed. If there are to be ongoing annual surveys in BMP, a subset of the existing sites need to be chosen, such that they can all be reliably repeated on an annual basis within the time frame that budgets will allow. The work to date provides a comprehensive baseline from which an ongoing program may be developed and refined within those budgetary constraints.
Neville Barrett, Rick Stuart-Smith, Carolina J. Zagal, Arianna Polacheck, Tim Lynch, Graham Edgar & Fran Clements
Tasmanian Aquaculture and Fisheries Technical Report Series