Study identifies water quality thresholds to protect fish during dredging

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A global study has assessed the potential risk from dredging to coastal fish and fisheries and identified guidelines that could protect 95 per cent of fishes from dredging‐induced mortality.

Dredging operations worldwide are forecast to intensify in the future to meet the demands of an increasing rate of coastal development and shipping activities and up to 20 per cent of fish species are likely to experience lethal and sub-lethal impacts as a result, according to results published in Conservation Letters.

The Western Australian Marine Science Institution Dredging Science Node brought together a team of researchers from universities and management agencies in Australia, led by Dr. Amelia Wenger at the University of Queensland, to develop evidence-based management guidelines to protect fish and fisheries from impacts associated with dredging.

The study found that more than 2,000 ports worldwide are within the range of at least one threatened species, while 97 ports are located within the range of five or more threatened species.

Figure 1: The global overlap between coastal ports and threatened marine fishes. The map shows the spatial distribution of threatened species, with the colors denoting the number of threatened species within particular areas. The black crosses indicate the presence of a port. The graph indicates the number of ports that fall within the geographic range of one or more threatened species (Wenger et al.)

It also determined that globally, between 2010 and 2014, 40.9 million tons of global commercial fisheries catch and 9.3 million tons of small-scale fisheries catch were extracted within five kilometres of a port, including many species known to be sensitive to sediment.

Figure 2: The spatial distribution and quantity of fishing activity that occurs within 5 km of a port. (a), (b) The location of commercial and small‐scale fishing activities and the quantity of catch in tons for each country where fishing activity occurs within 5 km of a port. (c) The countries where fishing of species known to be sensitive to sediment (see Table S3) occurs within 5 km of a port and the quantity of the catch. (d) The proportion of the fisheries catch of sediment‐sensitive species compared to the total fisheries catch that comes from within 5 km of a port for each country (Wenger et al.)

Dr Wenger said fish larvae were most likely to be affected by dredging sediment but that there were measures that could be taken to markedly increase the survival rate.

“While adult fish are unlikely to experience lethal impacts during dredging activities, we found that fish during early life history stages are at risk to lethal and sublethal impacts at suspended sediment concentrations and exposure durations regularly occurring during dredging operations,” she said.

“We found that maintaining suspended sediment concentrations below 44 mg/L  and for less than 24 hours would protect 95% of fishes from dredging‐induced mortality.

“Seasonal restrictions during peak periods of reproduction and recruitment could also protect species from dredging impacts,” Dr Wenger explained.

The thresholds developed in the study are considered to be a starting point for an adaptive management framework, to be used in conjunction with a monitoring program that evaluates the effectiveness of different management strategies at mitigating impacts to fish and fisheries.

Wenger A, Rawson C, Wilson S, Newman S, Travers M, Atkinson S, Browne N, Clarke D, Depczynski M, Erftemeijer P, Evans R, Hobbs JP, McIlwain J, McLean D, Saunders B, Harvey E (2018) Management strategies to minimize the dredging impacts of coastal development on fish and fisheries. Conservation Letters https://doi.org/10.1111/conl.12572

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

 

Category:

Dredging Science

Understanding the flow of suspended sediments across reefs

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A new study has developed a model that moves researchers a step closer to improved predictions of changes in shorelines adjacent to coral reefs and the transport of suspended sediments in reef systems.

This study at Tantabiddi, Ningaloo Reef in the northwest of Western Australia, deployed more than 20 instruments to measure how waves transform over the reef and in the lagoon, how currents develop and circulate throughout the reef system as well as the concentration of sediment in suspension in different zones of the reef.

The results published in Journal of Geophysical Research reveal that although variability in suspended sediment concentration occurs at tidal (or shorter) timescales in the different reef zones, the majority of the variability occurs over longer slowly varying (subtidal) timescales, which is related to the arrival of large swell waves at a reef location.
More than 20 instruments set up to measure suspended sediment flow at Tantabiddi, Ningaloo Reef (Image: Andrew Pomeroy)

The study, supported by Western Australia Marine Science Institute (WAMSI) Dredging Science Node, the Australian Research Council and the U.S. Geological Survey Coastal and Marine Geology Program captured low and high wave conditions, as well as a period of strong alongshore transport driven by wind. Wave generated currents flowed across the reef, separated in the lagoon and exited via the channels in the reef.

Lead author Dr Andrew Pomeroy from The University of Western Australia and the Australian Institute of Marine Science explained that up to 95% of the variability in the concentration of suspended sediments can be described by variability in waves and currents at tidal and longer timescales.

“This study shows that in coral reefs, suspended sediment transport varies at a number of different timescales – for example by waves, tides or time periods longer than tides such as storm systems, and by different processes – which is most important will depend on the question being asked,” Dr Pomeroy said.

Dr Pomeroy says the emphasis now needs to be placed on understanding and describing the physical processes that suspend sediment from the bed within coral reef canopies. Data within coral canopies as well as close to the bed is lacking because it is difficult to accurately obtain.

“This is important as it will enable changes in shorelines adjacent to reefs (by erosion or accretion) to be described as well as improve predictions of suspended sediment transport in coral reef environments for a range of conditions,” he said.

Pomeroy A, Lowe R, Ghisalberti M, Winter G, Storlazzi C, Cuttler M (2018) Spatial variability of sediment transport processes over intra‐ and subtidal timescales within a fringing coral reef system. Journal of Geophysical Research doi.org/10.1002/2017JF004468

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

WAMSI Bulletin May 2018

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Building trust among park managers and community through science

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Research has shown that the success of marine resource management is influenced by the levels of trust that exists between decision-makers and the rest of society.

In his latest paper, “Building trust among marine protected area managers and community members through scientific research: Insights from the Ningaloo Marine Park, Australia”, published in the journal Marine Policy, lead author Dr Chris Cvitanovic from the Centre for Marine Socioecology at University of Tasmania, says community engagement is critical to management success.

“We wanted to understand what, if any, impact the Ningaloo Marine Research Program had on residents of the region.  To do so we surveyed 125 local residents across Exmouth and Coral Bay, and found that the majority of residents believe that scientific research is important for the management of the marine park, and strongly support government investment in scientific research in the region,” Dr Cvitanovic said.

“More interestingly, the results also suggest that science undertaken through the Ningaloo Research Program has increased the extent to which community members trust local MPA managers and decision-makers, with many community members also suggesting that  this increase in trust has led to improved social and environmental outcomes in the region.”

“The extent to which scientific research can build and maintain trust among MPA managers and community members, however, is dependent on an effective  community engagement and outreach program that is implemented throughout, and following the completion of, the research,” Dr Cvitanovic said. “To this end our study also identified strategies and opportunities to further enhance  trust between community members and marine park managers in the Ningaloo region, for example, via targeted communication and engagement programs that account for different personality ‘types’ and the establishment of new citizen science programs.”

Co-author Dr Kelly Waples fom the Department of Biodiversity, Conservation and Attractions (formerly Parks and Wildlife) said one of the values presented by the Western Australian Marine Science Institution, and captured in the latest paper, has been the initiative and opportunity to go back and evaluate how effective the research program has been with respect to conservation outcomes.

“It has been a very valuable exercise to assess the elements of these large research programs that work well and where we may need to increase our efforts to ensure conservation outcomes for the marine environment and for the community,” Dr Waples said. “It does confirm that government investment in science has been very worthwhile and, given what we have learned, benefits will be improved in future programs.”

The research was funded by the Western Australian Department of Biodiversity, Conservation and Attractions, the Western Australian Marine Science Institution and the Centre for Marine Socioecology at the University of Tasmania.

 

Cvitanovic C, van Putten EI, Hobday AJ, Mackay M, Kelly R, McDonald J, Waples K, Barnes P (2018) Building trust among marine protected area managers and community members through scientific research: Insights from the Ningaloo Marine Park, Australia. Marine Policy doi.org/10.1016/j.marpol.2018.04.010

Confidence needed to turn ageing oil and gas infrastructure into reefs

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A review of Western Australian stakeholders has found that many are in favour of decommissioned oil and gas platforms being left to serve as artificial reefs as long as there is evidence to support the social, economic and environmental benefits.

The report was delivered by the independent Western Australian Marine Science Institution and jointly commissioned by the state government, fisheries, oil and gas, community, research, and regulatory sectors in response to the Blueprint for Marine Science 2050 report which identified better knowledge about the effects of decommissioning offshore infrastructure as a priority.

Over the next 10-20 years an increasing number of offshore oil and gas facilities around Australia will cease producing hydrocarbons and will require decommissioning. 

The process of decommissioning offshore oil and gas infrastructure is extremely expensive at a project level, and will become a major cost to the industry as a whole. Given the cost, safety issues and potential environmental risks associated with complete removal, there is interest, particularly from the oil and gas industry, in exploring other options.

 

Expected operational life of selected WA oil & gas projects. (Source: The Blueprint for Marine Science Report 2050. Pg 47 Estimates taken from Company Annual Reports)(Shaw et al 2018)

 

More than 120 stakeholders and association representatives from across sectors of the community from Perth, Exmouth, Karratha, Dampier, Port Sampson and Canberra were consulted. The group identified more than 900 issues, opportunities and concerns, which were developed into 30 questions that could be addressed through scientific research.

The priority science questions included:

  • What are the direct environmental impacts on fish species including from contamination, noise, habitat removal and cumulative ecological effects?
  • What is the timeframe for breakdown (corrosion) of the various standard components of oil and gas infrastructure?
  • What are the main contaminants following decommissioning, will they be released into the environment, and what are the toxicity issues?
  • Can the contaminants resulting from decommissioning be completely removed e.g. from sludge, scale, sands and drill cuttings?
  • Does oil and gas infrastructure (including pipelines) increase productivity of key fish species and biodiversity generally?

The consultation also identified a number of policy issues that are not science related such as managing navigation risks, who ultimately retains liability for infrastructure left in the ocean, the sharing of financial benefits from leaving infrastructure in situ and managing resource allocation of any new fisheries or environmental resources created.

A range of issues were raised in regard to improved communication with stakeholders about existing knowledge. The project also identified that a number of stakeholders were not satisfied with the current approaches to consultation regarding development operations, decommissioning activities, or policy discussion.

Lead author Dr Jenny Shaw said that while there is knowledge about the effects of decommissioning that can be drawn from the North Sea and the Gulf of Mexico, those surveyed believed it could not confidently be relied upon in Australian conditions.

“This was particularly true for issues around fisheries and environmental impacts given the uniqueness of Australian marine ecosystems,” Dr Shaw said. “The size and scale of the science questions that need to be addressed to resolve the uncertainties around decommissioning confirms that a strategic program of science projects that are unique to Australia’s offshore environment need to be developed to support company, regulator and community decisions on this subject.”

Although the information in the report was deemed to be relevant to oil and gas provinces across Australia, Western Australian stakeholder views were not assumed to be the same as those from other regions.

 

Shaw J.L., Seares P., Newman S.J. (2018) Decommissioning offshore infrastructure: a review of stakeholder views and science priorities. WAMSI, Perth, Western Australia. Pp 74. (www.wamsi.org.au/decommissioning-offshore-infrastructure-review-stakeholder-views-and-science-priorities)

EPA Gives Green Light for Beadon Creek Dredging

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Category: 

Dredging Science

Funding Boost for Western Australia’s Blue Economy

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Western Australia’s blue economy has received more than $2.6 million in funding over three years to support marine science.

The funds will go to the Western Australian Marine Science Institution to support the implementation of The Blueprint for Marine Science, which will guide long-term collaboration between all sectors operating in the marine environment.

The Blueprint will establish Western Australia as a hub for global marine science and support industry, community and government activities off our coast.

Australia’s blue economy is expected to be worth $100 billion by 2025. It encompasses many activities for economic growth, including renewable energy, tourism, fisheries, oil and gas, and maritime transport – balanced with the need to ensure the ongoing health of our oceans’ ecosystems.

More.

Listen to WAMSI CEO Dr Luke Twomey on ABC Country Hour here.

WAMSI Bulletin March 2018

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New Tool to Forecast Marine Response to Changes in the Kimberley

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An international team of researchers has developed and tested a conservation tool for the Kimberley region, in Australia’s far northwest, that can predict how marine species may fair under different climate and development scenarios.

A range of scenarios was modelled by scientists from CSIRO and Canadian-based ALCES under different management strategies to provide some insight into the potential pattern of responses by marine species over a 35 year period until 2050.

Changes in levels of conservation effort where compared against the three biggest environmental pressures of warming, rainfall and development.    

The researchers found that the dynamic Kimberley system, which is driven mostly by seagrass and algae (70%), reacted independently to many of the environmental pressures put on it.

 

Summary of result of scenario analysis

 

While variations in population growth made little difference to the overall outcome, groups and elements within the marine environment were found to respond differently to climate and development pressures, some showing dramatic variation between scenarios, and others showing very little.

WAMSI project leader, CSIRO’s Dr Fabio Boschetti, recently presented his team’s findings to Department of Biodiversity, Conservation and Attractions researchers and managers in Perth. He  explained that the use of modelling tools was not an ‘absolute’ prediction but attempts to say something about how the system may respond to different management decisions based on our current understanding.

“We analysed different conservation strategies ranging from doing nothing at all, to medium and high conservation efforts,” Dr Boschetti said. “Current conservation efforts are running at about medium.”

“What we did find interesting was that such a dynamic system was so independent of the forces,” Dr Boschetti said. “When we included a conservative 2.5 per cent population growth rate per year, which is quite high, we were still surprised to see it made such a small imprint on the system as a whole. It would be interesting to model spikes in evolution, such as unusual warming or rain events.”

Dr Hector Lozano-Montes (CSIRO) collated information from the results of 25 projects under the Western Australian Marine Science Institution’s (WAMSI) Kimberley Marine Research Program in order to describe the ‘system’ and develop an interactive dynamic food web based on how much marine biomass there is and where it is.  This work has resulted in the development of a more detailed picture of the complete interactions that occur in the Kimberley marine system.

The Ecopath system

 

Links:

Knowledge Integration and Management Strategy Evaluation Modelling_WAMSI KMRP project 2.2.8 Report_Boschetti et al 2017_Final

WAMSI Project Page: www.wamsi.org.au/modelling-future-kimberley-region

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

 

Category: 

Kimberley Marine Research Program

Kimberley coastline key to monitoring shorebird decline

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Researchers looking into the declining number of long-distance shorebirds say, while there is clear evidence that changes in Australian populations are strongly influenced by factors outside of the country, there may also be losses due to habitat pressure in the Kimberley.

A shorebird monitoring project, supported by the Western Australian Marine Science Institution, found some evidence suggesting that local habitat preferences of shorebirds in northwestern Australia have changed in response to human disturbance of roost sites, mangrove incursion on some beaches in northern Roebuck Bay.

The study, led by Danny Rogers and Chris Hassell from the Australasian Wader Studies Group, focussed on the coastlines of Roebuck Bay and Eighty Mile Beach.

Organic pollution of groundwater from Broome has contributed to algae blooms in Roebuck Bay, which may have detrimental effects on the food available to shorebirds.

“It is not yet clear whether these problems have only resulted in local relocation of shorebirds, or whether it affects their survival rates and population counts,” Danny Rogers said.

Bottom row: Greater Sand Plovers (Charadrius leschenualtii),
Top row (one mostly hidden): Great Knot (Calidris tenuirostris)
At right centre: Red Knot (Calidris canutus)
(Image: Danny Rogers )

Shorebirds carry out long-distance annual migrations between their feeding grounds in the arctic and non-breeding grounds in the southern hemisphere.

During their non-breeding season, migratory shorebirds are broadly distributed along those parts of the northern Western Australian coast with extensive tidal flats. Especially large concentrations are in Roebuck Bay and the northern 80 kilometres of Eighty Mile Beach.

Of the 41 shorebird species occurring regularly along this coastline, 18 species occur in internationally significant numbers (>1% of the population in the East Asian – Australasian Flyway). In total, more than 635,000 migratory shorebirds depend on the tidal flats of the northwestern Australian coast.

“Given the strong external influences on shorebird numbers in Australia, it is clear that Australian-based monitoring serves an important purpose as a barometer of shorebird populations throughout the East Asian – Australasian Flyway,” Danny Rogers said. “As the most important non-breeding region for shorebirds in Australia, Kimberley coastline monitoring is a very important part of this monitoring effort.”

Links:

Evaluating the impacts of local and international pressures on migratory shorebirds in Roebuck Bay and Eighty Mile Beach_WAMSI KMRP project 1.2.6 Report_Rogers et al 2017_Final

WAMSI Project Page: www.wamsi.org.au/pressures-migratory-shorebirds

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program