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

Where to find WAMSI science data

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Data from the Western Australian Marine Science Institution’s WAMSI-2 projects (2012-2018) is discoverable and available for reuse.

WAMSI Data Manager, Luke Edwards from the Pawsey Supercomputing Centre, manages the collection and storage of data from the programs including:

WAMSI Dredging Science Node

Kimberley Marine Research Program

Wheatsone sawfish offsets project

“One of the great legacies of the WAMSI science is that the data is made discoverable for ongoing and future research,” Luke Edwards said. “Data is made public after the default 18 month embargo period to enable researchers to publish.”

For example, KMRP project 1.3.1 on Reef Growth and Maintenance has data publicly available now.  The link to the metadata record is http://catalogue.aodn.org.au/geonetwork/srv/eng/metadata.show?uuid=7ab491d2-9507-428c-aed1-091d2aaed521.

Within the metadata, there are links to the Pawsey Data Portal, where it is held.

As well as the Pawsey Data Portal, data is stored in the CSIRO Data Access Portal (DAP) and AIMS Data Centre.

Data discovery and access starts via the AODN catalogue – http://catalogue.aodn.org.au/geonetwork/.  To see all WAMSI 2 projects, type WAMSI 2 into the “Title” search box.

Other discovery pathways are being developed including via the WA Open Data catalogue – https://catalogue.data.wa.gov.au/group/wamsi.

Other WA Government marine data is available here – https://catalogue.data.wa.gov.au/group/0-wa-marine-map.

 

Category:

Sawfish Project Kimberley Marine Research Program Dredging Science

Dredging Science: Understanding how low light levels can affect coral health

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Research has confirmed that some coral and important reef building algae can sustain being exposed to low light conditions for up to 10 consecutive days before their health is critically affected.

The findings have important implications for the environmental impact assessment and management of dredging operations, which cause sediment plumes.

The results of the Western Australian Marine Science Institution’s Dredging Science Node research, conducted in specially developed tank systems at the AIMS National Sea Simulator (SeaSim), have been published in Scientific Reports.

Lead researcher Pia Bessell-Browne from The University of Western Australia Oceans Institute, Centre for Microscopy, Characterisation and Analysis and Australian Institute of Marine Science said corals and important reef building algae are particularly susceptible to light limitation resulting from elevated sediment particles in the water column which can be generated by naturally occurring events, such as cyclones, as well as coastal development activities such as dredging.

 

Experimental tank set up at the AIMS National Sea Simulator used to determine the impacts of 6 light levels on both coral and algal health. (SeaSim)

 

“This study has determined light levels that need to be maintained in order to reduce negative impacts on the health of coral and reef building algae,” Ms Bessell-Browne explained. “When corals do not receive adequate light, the algae that live within their tissues and provide them with up to 90 per cent of their daily energy requirements leave, meaning the corals are without their main food source and can starve if this condition is maintained over extended time frames.”

A range of low light levels were investigated and their impacts on several species of corals, along with juvenile corals and a species of reef building algae were determined.

 

Photographs of representative A. millepora and P. acuta fragments after 30 d of exposure to the six daily light integral (DLI) irradiance treatments of ~0, 0.02, 0.1, 0.4, 1.1 and 4.3 mol photons m−2 d−1 (Bessel-Browne et al., (2007))

 

“The results demonstrate that both corals and algae are sensitive to exposure to low light conditions for more than 10 consecutive days,” Ms Bessell-Browne said. “Juvenile and adult corals have similar low light tolerance, while the reef building algae is more sensitive to the low light conditions than the corals.”

The thresholds determined by these research findings are expected to contribute to the environmental impact assessment and management of dredge programs where these coral and algae species occur in the field.

Bessell-Browne P, Negri A.P., Fisher R, Clode P.L., Jones R (2017) Impacts of light limitation on corals and crustose coralline algae Scientific Reports doi:10.1038/s41598-017-11783-z

 

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

Branching corals are better at rejecting dredging sediment

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Researchers working to better predict the likely environmental impacts associated with dredging have found that branching corals are highly adept at cleaning their surfaces of depositing sediments compared to other coral structures.

The Western Australian Marine Science Institution Dredging Science Node study assessed the sediment rejection ability of eight common Indo-Pacific coral species from three different morphologies (coral structures) in a series of short-term exposure tests over a range of sedimentation levels and one longer-term exposure test at a high sediment concentration level.

Australian Institute of Marine Science (AIMS) scientists tested: branching corals, that are made up of thick upright and horizontal branches;  foliose coral, that are more flattened and plate-like; and massive corals, that are characteristically ball or boulder-shaped.

The results, published in the Marine Pollution Bulletin, show that sediment accumulation rates on live corals and dead (enamel-covered) skeletons varied between morphologies, with branching species often more adept at self-cleaning.

Lead researcher, Dr Alan Duckworth explained corals have a range of different ways for shifting sediment primarily involving; mucus entrapment, hydrostatic inflation (the ability of corals to expand tissues, resulting in a shape which better sheds sediments), tentacle movement and ciliary action, which is small threadlike appendages producing strong swirls of water that draw nutrients toward the coral, while driving away waste products.

“These ‘active’ (energy-requiring) processes work in combination with ‘passive’ forces associated with gravity,” Dr Duckworth said. “Both the macroscale morphology (growth form, branch thickness and spacing) and microscale morphology (corallite size and shape) affect how sediments settle, collect and are cleared from the surface.

“We found that flow rates (0–17 cm s− 1) significantly affected the coral’s ability to shed sediment as did differences in particle sizes, with coarse silt rejected faster than fine silt, but only at very high (235 mg cm− 2) deposition rates.

“Noncarbonate siliciclastic sediment was rejected faster than carbonate sediments, and smothering for many days by millimetres of low organic content carbonate sediment resulted in bleaching, but no mortality.

“Estimating the sedimentation rate where the self-cleaning ability of corals is exceeded will improve our ability to make scientifically sound predictions of the likely extent, severity, and persistence of environmental impacts associated with dredging and can also be used with water quality monitoring during dredging to inform adaptive management,” Dr Duckworth said.

Duckworth A, Giofre N, Jones R (2017) Coral morphology and sedimentation Marine Pollution Bulletin doi.org/10.1016/j.marpolbul.2017.08.036

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

Study finds early warning triggers for corals during dredging operations

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Effective management of dredging operations requires understanding the effect of the activities on the surrounding environment including important habitats like coral. New research conducted by researchers from the Australian Institute of Marine Science (AIMS) and The University of Western Australia (UWA) has supported decision-making in this field by defining a series of thresholds that can be used to reliably predict the impact of water quality levels on coral health.

The study, conducted as part of the Western Australia Marine Science Institution Dredging Science Node, used a comprehensive water quality and coral monitoring dataset collected by industry during a past dredging project that occurred off Western Australia.

“Essentially, we’ve used this data to understand how turbid the water can get before coral health begins to be affected,” AIMS Ecological Risk Assessment Modeller and lead author Dr Rebecca Fisher said.

The researchers examined water quality measurements, such as light levels, turbidity and sedimentation, and compared them to observed changes in the health of hundreds of individually marked corals that were surveyed each fortnight. This led to an improved understanding of how corals in shallow, reef environments respond to changing water quality which then allowed the team to develop water quality ’trigger-points‘– or thresholds – at which the corals were negatively affected. Cutting-edge modelling techniques were applied to account for uncertainty in the assessment of coral health in order to increase the reliability of the water quality thresholds.

Figure 3 from Fisher et al –  Example coral mortality and water quality data used for analyses, showing time series of proportional live coral cover measurements for representative colonies of each taxa (black circles) and mean daily turbidity (NTU; red lines). Solid black lines represent GAM smooths (see Appendix S2 for details) with grey bands indicating 95% confidence bounds, fitted using a beta distribution to the proportion of live coral cover. Right hand panels show images of each colony at the start of dredging and immediately preceding the start of bleaching (day 203, used as the end point in the present analysis, Figure 2)

 

“The dataset used was particularly valuable because it contained measurements of water quality and coral health close to the dredging, in areas where it was expected and approved by the regulators that corals would be impacted through to areas further away where there was no effect,” Dr Fisher explained. “It’s important to understand how corals respond when exposed to a full range of conditions, including those that are more extreme. This provided the information needed to build a pressure:response curve: without observing those upper limits, you just have no way of finding thresholds.

“This work will be useful to industry to improve confidence in managing dredging operations to protect the environment. It will assist managers and regulators assessing future proposals to provide confidence about the potential impacts to coral reef environments, based on the predicted water quality conditions,” Dr Fisher said.

Links:

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside Energy, Chevron Australia and BHP Billiton 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 Australia, Woodside Energy and Rio Tinto Iron Ore. The commercial entities had no role in data analysis, decision to publish, or preparation of the manuscript.

 

Category:

Dredging Science

A thin layer of sediment impacts coral settlement behaviour

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Further research into dredging pressures on coral has revealed that even a very fine layer of sediment can prevent coral larvae from settling on a surface and building on the coral community.

Successful recruitment, where coral larvae attach and establish themselves as part of the adult community, is important for sustaining and recovery of coral reefs.

The research published in the Science of The Total Environment for the Western Australian Marine Science Institution’s Dredging Science Node found that coral larvae avoid sediment-covered surfaces, but will settle nearby on clean substrates including grooves and downward facing surfaces.

 

A conceptual diagram showing possible coral settlement behaviour and cause–effect pathways in response to sediment stressors, such as suspended sediments, deposited sediment and reduced light. (Ricardo et al)

 

The study also looked at how sediment affects coral behaviour with regard to calcareous red algae (CRA), which are rock-hard calcareous algae that contribute significantly to reef calcification and cementation, and induce larval settlement of many benthic organisms including corals.

Study author, Gerard Ricardo, from the Australian Institute of Marine Science, looked at coral settlement on sediment-covered and sediment-free surfaces under controlled conditions at the National Sea Simulator facility in Townsville.

 

VIDEO: A time-lapse of Acropora millepora larvae settling on calcareous red algae (CRA) recorded over 2.5 hours.

 

VIDEO: A time-lapse of Acropora millepora larvae settling on sediment-covered and sediment free calcareous red algae (CRA).

 

“We found a very fine layer of sediment prevents larvae from settling in two ways,” Gerard Ricardo said. “First by creating a physical barrier over the CRA, and second by deteriorating the quality of the CRA. This means that sediment deposited during dredging, and even following some natural deposition events, may influence where larvae settle on a reef.”

“These results have implications for reef recovery and resilience because of the overall reduction in optimal-substrate space, and the flow-on effects for newly-metamorphosed corals that settle in sub-optimal locations,” Mr Ricardo said

 

Ricardo G.F., Jones R.J., Nordborg M, Negri A.P. (2017) Settlement patterns of the coral Acropora millepora on sediment-laden surfaces. Science of the Total Environment doi.org/10.1016/j.scitotenv.2017.07.153

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside Energy, Chevron Australia and BHP Billiton 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 Australia, Woodside Energy and Rio Tinto Iron Ore. The commercial entities had no role in data analysis, decision to publish, or preparation of the manuscript.

Category:

Dredging Science

Award goes to WAMSI sea sponge responses to dredging project

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Three researchers from Western Australian Marine Science Institution’s Dredging Science Node recently presented their findings at the World Sponge Conference in Ireland, with PhD candidate Brian Strehlow winning a prize for best student presentation.

Mr Strehlow, from The University of Western Australia, won the prize for best student presentation in the category of organismal biology, for his full-length presentation (12 minutes with 3 minutes for questions) which elaborated on the mechanisms of resilience to sediment-related stress that some sponge species possess.

“Identifying relative impacts by different types of pressures in combination with thresholds and guidelines will assist managers to reduce the risks and severity of impacts from dredging developments,” Mr Brian Strehlow said.

As part of the presentation, short videos showed that sediments that enter a sponge (Video 1) can be expelled after a return to controlled conditions (Video 2).

 

VIDEO 1: 3D X-ray of Ianthella basta after 48 hours of acute sediment exposure to siliciclastic sediments (shown in white) in the high sediment (135 ± 30 mg L-1) treatment

 

VIDEO 2: 3D X-ray of Ianthella basta after 3 weeks of recovery in control conditions (0 mg L-1) after 48 hours of acute sediment exposure to siliciclastic sediments in the high sediment (135 ± 30 mg L-1) treatment.

 

“Describing these mechanisms was an important part of determining the pressure-response relationships of sponges to sediment-related stress,” Mr Strehlow said.

Dr Mari Carmen Pineda and Team leader Dr Muhammad Abdul Wahab, both from the Australian Institute of Marine Science, also presented talks on their dredging science results.

Whereas Brian Strehlow’s presentation focused on the mechanisms underpinning the resilience of some species, Dr Pineda’s talk (12 min) elaborated on the dose:response relationships and cause:effect pathways for multiple sponge species exposed to sediment stress.

Dr Abdul Wahab presented a talk entitled, “Effects of dredging on benthic filter feeding”. This talk also presented results of the WAMSI research, including field surveys of filter feeding communities before and after dredging.

 

WAMSI project sponge group
Top: Brian Strehlow (PhD candidate; winner best student talk)
Bottom left to right: Cecilia Pascelli (PhD candidate; winner best student talk), Heidi Luter (Post-doc), Blake Ramsby (PhD candidate), Muhammad Abdul Wahab (Post-doc), Mari-Carmen Pineda (Post-doc)

 

Presentations

Pineda MC, Strehlow B, Duckworth A, Jones R (2017) Pressure-response relationships of sponges to dredge pressures – a laboratory approach. 10th World Sponge Conference. Sponges & their Environment ABSTRACT

Strehlow B, Pineda MC,  Duckworth A, Clode P, Webster N (2017) Sub-lethal stress responses of sponges to dredging pressures. 10th World Sponge Conference. Sponges & their Environment. ABSTRACT

Wahab MAA, Fromont J, Gomez O, Fisher R, Jones R (2017) Effects of dredging on benthic filter feeding communities. 10th World Sponge Conference. Ecosystems & Environment. ABSTRACT

Posters

Fromont J, Wahab MAA, Gomez O, Ekins Merrick, Goverdina Geerruida Grol M, Hooper J.N.A. (2017) North-western Australia: a sponge biodiversity hotspot. 10th World Sponge Conference ABSTRACT

LINKS:

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside Energy, Chevron Australia and BHP Billiton 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 Australia, Woodside Energy and Rio Tinto Iron Ore. The commercial entities had no role in data analysis, decision to publish, or preparation of the manuscripts.

Category:

Dredging Science

Sponges show varying levels of tolerance and resilience to sediment stress

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Different sponge species adopt different strategies to cope with sediments in turbid environments and while many of these alleviate pressure in the short-term, researchers have found that longer-term exposure may still compromise fitness and overcome the sponge’s ability to withstand sediment stress.

Sponges are ecologically important filter feeders that employ a wide variety of mechanisms to cope with turbid environments, such as those affected by dredging activity.

As part of a Western Australian Marine Science Institution Dredging Science Node project supported through co-investment from industry and the Australian Institute of Marine Science (AIMS), a team of researchers led by Dr Nicole Webster tested the sensitivity of sponges to poor water quality conditions. Five main experiments were performed by Dr Mari-Carmen Pineda and PhD student Brian Strehlow at the National Sea Simulator (SeaSim).

The researchers used tanks equipped with an automatic sediment delivery system in which all relevant environmental parameters were also electronically controlled. The latest results have been published in three separate articles in Scientific Reports.

 

PhD student Brian Strehlow and intern Miriam Sternel working on effects of combined dredging pressures experiment at SeaSim (MCP)

 

High concentrations of suspended sediments in the water column were found to interfere with suspension feeding, the strategy used by most sponge species to uptake their food from the seawater.

 

Sponges smothered by sediments and mucus layer in Carteriospongia foliascens (MCP)

 

Sediments were found to clog sponges’ internal chambers (aquiferous system), which affect their nutritional stores in the long term. In addition, light reduction associated with high turbidity also negatively affected the sponge photosymbionts, which are another source of nutrition for some species. However, most species also possessed an array of different mechanisms for coping with those pressures, such as the production of mucus that traps sediments or oscular closure and tissue regression to minimize the risk of clogging.

 

Tissue regression in Ianthella basta (MCP)

 

“Although sponges seem generally resilient to sediment pressures and can present several strategies to ameliorate their effects, we believe that long-term exposure will adversely impact their energetic resources which can certainly affect sponge population dynamics and their important roles in the oceans,” Dr. Pineda said.

Sub-lethal thresholds for suspended sediment concentrations and light intensity were also identified for some sponge species during the experiments.

“These thresholds can be used to help proponents to more reliably predict the effects of their dredging proposals on sponge communities and also to design dredging programs to minimise impacts overall,” Dr. Pineda said. “Also, where the sponge species we used in our experiments occur in the field, they could be used as sentinels in dredge environmental monitoring and management programs and, with knowledge of the thresholds and indicators of stress we have identified, used to reduce risks on these important benthic communities.”

Future experiments will focus on the effects of dredging pressures on sponge larvae and juveniles, as early life stages may be more vulnerable than adult sponges.

LINKS:

Pineda MC, Strehlow B, Sternel M, Duckworth A, Jones R, Webster N.S. (2017) Effect of suspended sediments on the sponge holobiont with implications for dredging management. Scientific Reports. doi:10.1038/s41598-017-05243-x

Pineda MC, Strehlow B, Sternel M, Duckworth A, den Haan J, Jones R, Webster N.S. (2017) Effects of sediment smothering on the sponge holobiont with implications for dredging management Scientific Reports 7, Article number: 5156 doi:10.1038/s41598-017-05243-x

Pineda MC, Strehlow B, Kamp J, Duckworth A, Jones R, Webster N.S. (2017) Effects of combined dredging-related stressors on sponges: a laboratory approach using realistic scenarios Scientific Reports doi:10.1038/s41598-017-05251-x

Project Page: www.wamsi.org.au/filter-feeder-responses-dredging

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside Energy, Chevron Australia and BHP Billiton 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 Australia, Woodside Energy and Rio Tinto Iron Ore. The commercial entities had no role in data analysis, decision to publish, or preparation of the manuscript.

Category:

Dredging Science

Rare soft corals feature in Kimberley photographic field guide

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More than 90 images, giving a glimpse into the rare soft coral gardens of Australia’s remote northwest, have been compiled in a photographic field guide by Dr Monika Bryce of the Western Australian Museum.

Octocoral (non reef-building coral) specimens collected on five expeditions conducted in 2015 and 2016 in and around Camden Sound, Maret Island, Eclipse Islands and Lynher Bank have been identified and the species are characterised in the guide.

The locations for investigation by the Western Australian Marine Science Institution’s Benthic Biodiversity project team were selected with the WA marine park initiatives in mind, in particular Lalang-garram/Camden Sound Marine Park and the North Kimberley Marine Park in the Cape Bougainville-Cape Londonderry region.

The ship based surveys focussed on the deeper areas, from around 12-100m below low tide, where little information is available from previous Kimberley studies. Samples were also taken in nearshore areas at low tide reef walks and sediment grabs.

The guide is designed to walk scientists through the characters they require to identify species of octocorals. It features images of the octocoral species, and the sclerites that form their skeletons which are used to determine species identifications.

 

Chironephthya sp. 2  Chironephthya sp. 2  sclerites (that form their skeletons)

 

“The simplicity of the guide belies the complex taxonomic science that underpins it, and the enormous amount of time it has taken Monika to identify the 92 species presented in it,” Dr Jane Fromont, Head of Department of Aquatic Zoology at the Western Australian Museum said.

Video of sponge gardens at Nick’s Rock.

“There are rich sponge and octocoral gardens in the Kimberley and this guide gives a snapshot of the octocoral biodiversity.

“This is the first identification guide of octocorals of the Kimberley region,” Dr Fromont said. “As a new resource into a virtually unknown fauna it will be incredibly useful to researchers attempting to identify these animals. It also provides general estimates of abundance and rarity, and the habitats where the animals are found, and is therefore important for managers of the region.”

 

 

Ultimately all available data will be drawn together to provide an overview of the large scale trends in habitats along the Kimberley including:

  • A habitat map identifying the major seabed habitat types throughout the Kimberley.
  • A better understanding and appreciation of the importance of marine biodiversity in the Kimberley (including number of species and identification of species new to science and/or new to the region)
  • An improved ability to plan and manage marine protected areas in the Kimberley.

 

“The Kimberley is an increasingly active, multiple-use marine region, with a growing need for accessible environmental and socio-economic information,” WAMSI Benthic Biodiversity Project leader, Dr Andrew Heyward (AIMS) said. “These are voyages of discovery, which is inherently exciting for the scientists. We expect the project will reveal much about life on the seabed in this region and make a useful contribution to planning and management.”

WAMSI’s joint venture partners, the Australian Institute of Marine Science, CSIRO, Curtin University and Tradional Owners also supported the fieldwork and provided laboratory facilities.

The Octocoral Field Guide, Kimberley, Western Australia can be found at:

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

 

Category:

Dredging Science