research projects

Macro Colonisation Under the Busselton Jetty (F. Cosgrove 2013)

Busselton Jetty, once a functioning port for the town of Busselton was retired in 1973 and has since become a popular tourist attraction for both visitors to the underwater observatory and divers to the colonised wood piles underneath. Renowned as one of the best shore dives in Australia the originally wood piled jetty is home to established colonising assemblages and their diverse associated marine life. In 2004 a fire destroyed over half of the jetty, with extensive funding; reconstruction was finished in 2011 with the addition of new steel piles. With the addition of these steel piles came the opportunity to study the influence substrate had on the composition of resident colonising assemblages. Furthermore the effect shading and temporal variation had on the composition of colonising assemblages was also investigated. Results of this study indicated that although colonising assemblages differed significantly between substrates and lighting conditions, the extent of these differences in community structure was minimal in the case of substrate type and almost negligible in the case of shading. Temporal variation was the biggest contributor to changes in colonising assemblages with the first twelve months of colonisation dominated by opportunistic organisms with short life spans resulting in dynamic patterns of colonisation.

Diversity and Abundance of Nudibranchia under the Busselton Jetty with the Influence of Water Temperature (B. King 2014)

 In the summer of 2010/2011 an anomalous warming event caused record high ocean temperatures along the Western Australian coast and resulting in the mortality and range extensions of marine organisms (Pearce and Feng 2013). Nudibranchs at the Busselton Jetty were reported to have disappeared for a short time after this anomaly (Mischa 2011) and sparking interest into the effects of anomalous events and climate on these organisms. An underwater diver census was conducted to take quantitative observational data of nudibranch abundance and diversity at three different sites along the jetty. Additionally, historical census data of organisms sighted and recorded by staff at the Observatory was used to find a relationship between temperature and monthly sighting percentages at the jetty. Sea temperatures have been consistently measured at the jetty since 2001, giving a way of comparing monthly and annual temperature averages to the census data. The diver census found no diversity and no significant temporal change in abundance at each of the sites over the sampling period. The samples were dominated by observations of C. brevicaudatum, however highly distributed individuals and low abundance values returned little results to analyse. The Observatory census however showed that the sighting percentage of the nudibranch H. saintvincentius had a strong significant correlation with monthly temperature averages. Other nudibranchs recorded in the Observatory census did not have any significant correlation with temperature, however further conclusions could be made with more quantitative measurements of nudibranch abundance over a longer time period.

Colonisation in a South Western Australian Artificial Reef: A Rehabilitation Study 

(S. Teede 2018)

In March 2015, a number of timber jetty piles beneath Busselton Jetty in Western Australia were wrapped with a protective marine wrap, MarineGard 60 in order to reduce the impact of biological attack from marine borers weakening the heritage listed structure. In order for the protective wrap to be applied to the timber piles, established marine fouling communities were removed from the piles by scraping and high-pressure water blasting. The ecosystem beneath Busselton Jetty is diverse, supporting over 300 marine species and is a well-known recreational fishing and diving site among both locals and visitors. In an attempt to remediate the environmental damage caused by wrapping the jetty piles, a rehabilitation method was established. This method involved the use of ‘corals of opportunity’ fragments being reattached to the wrapped jetty piles. Fragments used for the restoration consisted of a range of invertebrate species including soft corals, sea sponges and ascidians. This paper reviews the success of the rehabilitation method used and also quantifies the differences in colonisation between piles wrapped with MarineGard 60, rehabilitated piles and piles in a natural state of colonisation, using biomass, percentage cover and diversity indices. Biomass and percent cover varied significantly between each of the pile treatment types, with the rehabilitated piles showing a similarity to jetty piles in a natural state of colonisation. Very low biomass was observed in the piles wrapped with MarineGard 60 and there was little habitat complexity created by those organisms colonising the wrap substrate. Diversity indices showed the soft coral Carijoa sp. dominates the community on in the natural state piles but reduces overall diversity; the dominance of this species was emerging in the rehabilitated piles. Diversity was higher among the rehabilitated and wrapped piles as the disturbance returned the fouling community to an earlier state succession with high competition for space and food resources.

 

Ocean Accounting Pilot for Geographe Marine Park (IDEEA Group 2020)

The Australian Government Department of Agriculture, Water and the Environment is leading the implementation of Environmental Economic Accounting: A common National Approach Strategy and Action Plan whereby all Commonwealth, state and territory governments have agreed to work together to develop a consistent approach to environmental-economic accounting across Australia. The ‘Ocean accounting pilot for Geographe Marine Park’ project is a pilot project under this strategy. The project has three key objectives:
1) Provide structured environmental, cultural, social, and economic information to contribute to the Monitoring, Evaluation, Reporting and Improvement (MERI) system informing ongoing management of Geographe Marine Park
2) Improve understanding of how ocean accounts can assist the sustainable management of marine resources
3) Trial the internationally accepted frameworks and Technical Guidance on Ocean Accounting in an Australian marine context and assess feasibility for broader application.
This report, compiled by IDEEA Group and Hydrobiology for the Australian Government
Department of Agriculture, Water and the Environment, is an assessment of the data available to populate Ocean Accounts for Geographe Marine Park.

Report available here

The “marine heatwave”off Western Australia during the summer of 2010/11

(A. Pearce, R. Lenanton, G. Jackson et al 2011)

* Water temperatures off the south-western coast of Western Australia rose to unprecedented levels during February and March 2011, and this warming event has been termed a “marine heat wave”. While surface temperatures were more than 3°C above the long-term monthly average over an extended area in February 2011, the temperature in some localised areas in coastal waters exceeded the long-term monthly average by 5°C for periods of a day or two in late February/early March.
* A scientific Workshop was organised on Thursday 5 May, 2011 to review the oceanic processes and biological/fisheries consequences of the heat wave and to provide a means for capturing much of the anecdotal information.
* This heat wave, which coincided with an extremely strong La Niña event and a record strength Leeuwin Current, is viewed as a major temperature anomaly superimposed on the underlying long-term ocean-warming trend.
* While sudden changes in water temperature have been recorded in waters off the Western Australian coast in the past, there have been no previous records of such strongly elevated temperatures.
* Biological effects reported to date include fish and invertebrate deaths, extensions and
contractions in species distributions, variations in recruitment and growth-rates, impacts on trophic relationships and community structure, and variations in catch rates of exploited species.
* As such, the elevated water temperatures were viewed as resulting either in mortality or in a variety of “sub-lethal” effects, both of which can have either short or long-term implications.
* These observed and expected biological consequences are based primarily on anecdotal
information collected during or directly after the passage of the heat wave. However, as results from ongoing research and monitoring programs become available, a more comprehensive and considered view of the effects will be forthcoming in the form of peer-reviewed journal papers.
* While widespread mortality of fish and invertebrates were reported, none were shown to be attributable to disease.

Report available here