The adventures of team sawfish

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Blog by Team Sawfish

Sweltering heat, mosquitoes, angry crocodiles and swarms of flies characterise the typical late dry season (September-November) in northern Western Australia. And it’s here that Team Sawfish has found itself for the past 15 years , as we continue our research on sawfish. This past October, Dr Ruth Leeney of Protect Africa’s Sawfishes and Dr Barbara Wueringer of James Cook University decided to brave these conditions and joined our team during our month long expedition on the Fitzroy River.

The main objective of our trip was to investigate how unnatural instream barriers, such as dams, may impact on the movement and health of the largetooth sawfish (Pristis pristis), which inhabits freshwater rivers and lakes as juveniles.Dams and other barriers in rivers and estuaries can block the movements of fish and which may prevent them from accessing food, spawning grounds or other important resources.

The Camballin Barrage, a small weir on the Fitzroy River used for irrigation for cattle and crops.

This work is part an ongoing project that is gathering information from several rivers throughout Western Australia.

The Fitzroy River is an ideal site for this study. It’s one of the largest known nurseries of the largetooth sawfish and it has instream barriers of various sizes, including a small weir (a type of dam often used for irrigation) and several road crossings. 

During our October trip we sampled various pools within the river that were located between the river mouth and 380 km (236 miles) upstream from the river mouth. From these pools we captured seven different sawfish. This is fewer fish than we typically see, and was largely due to the lack of captures of young of the year (YOY; fish pupped within the year). The number of YOY that we captured earlier in the year was also relatively low, which suggests this may have been a poor year for YOY.

All captured sawfish were only 2-3+ years old but still had an average length of 205 cm (6.7 feet)! In addition, the majority of these fish were recaptures of those that we had previously tagged with individually numbered Rototags (i.e. cattle ear tags). Two of these sawfish were initially tagged 2 to 3 years ago! Long-term recaptures like these allow us to gather some important information on the distribution, movements and growth of this species.

Although we can collect some of this vital information through recapturing sawfish for the few months of the year that we’re in the field, we also rely on local and visiting fishers to report their encounters. (see instructions below on how to report an encounter with a sawfish).

The sawfish that we did capture were also tagged with small acoustic transmitters. These transmitters emit a unique acoustic signal that is picked up and recorded by receivers, which we have installed throughout the river. Data from these transmitters and receivers will help us to better understand sawfish movements and how dams and river levels affect them.

Although we tag the animals in the dry season, it is the data from the wet season we are most interested in. Only during the wet season are the barriers submerged by rising river levels, and we want to know at what river level sawfish move beyond these barriers.

Release of a tagged largetooth sawfish

As well as capturing the largetooth sawfish, we had hoped and expected to find the smaller dwarf sawfish (Pristis clavata), which we have been monitoring over the last few years. Although the largetooth sawfish is the only sawfish that lives in freshwater for long periods of time, the dwarf sawfish, which lives in marine and estuarine environments, is attracted to the estuarine pools of the Fitzroy River in the late dry season, when these pools become more salty (around 35 ppt; similar to the ocean). This increase in salt in the late dry season is due to a decrease in freshwater flow and the constant transport of ocean water into the pools by the large tides. Typically during this time we primarily find dwarf sawfish in the estuarine pools, as the majority of the largetooth sawfish appear to leave the area. This year however, we were surprised to find a couple largetooth sawfish but unfortunately did not find any dwarf sawfish.

After a month in the field our food supplies, energy levels and time ran out. As we left the sawfish and the river behind, our team agreed that in spite of a few minor setbacks our trip was a success. We were able to tag a few new sawfish and collected some important recapture data. This will help us to better understand and inevitably help to advance conservation efforts for these threatened sawfish.

Although, we had to finally part ways with our esteemed and much appreciated colleagues, we had enjoyed the time spent with them and the memories of fly bites, tasty porridge, not so tasty tree sap and most importantly, the sawfish.

Pictured is the October 2014 Team Sawfish field crew. Missing are Dr David Morgan and James Keleher.

Pictured is the October 2014 Team Sawfish field crew. Missing are Dr David Morgan and James Keleher.

To report a sawfish captured in Western Australia and for more information regarding Team Sawfish please visit http://www.freshwaterfishgroup.com/team-sawfish.php. If you encounter a tagged or untagged sawfish outside of Western Australia please visit the Sawfish Conservation Society at www.sawfishconservationsociety.org, or the International Sawfish Encounter Database at www.flmnh.ufl.edu/fish/sharks/sawfish/sawfishdatabase.html.

This research was funded by Chevron Australia and was made possible by the Western Australian Marine Science Institution.

 

 

 

Category: 

Sawfish Project

Northwest seagrass in a world of its own (in the lab)

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In the second part of our report into measuring the effects of light reduction and sediment burial to determine the capacity for northwest seagrasses to withstand change, we move from the field to the lab for some surprising results.

The WAMSI Dredging Science Node project has brought together researchers from Edith Cowan University (ECU), The University of Western Australia (UWA) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to test tolerance levels that have

UWA’s seagrass growth facility (Crawley campus)

previously never been determined for seagrass species in the far northwest.

Dr John Statton manages the research’s experimental tank system at UWA’s seagrass growth facility (Crawley campus) where the effects of light stress and sediment burial are being measured under controlled conditions on three commonly co-occurring northwest Australian

tropical seagrass species (Halodule uninervis, Halophila ovalis and Cymodocea serrulata).

“We’ve been keeping plants under different light intensities for a number of weeks now. It was quite clear that within the first three weeks the plants at low light intensities (4 and 11% surface irradiance) had lower photosynthetic rates and growth rates than unshaded plants.

“Some of the responses were as expected but what was interesting is that it took a long time for all except one of the species, Halophila ovalis, to die,” Dr Statton said.

Halophila ovalis

Halophila ovalis has the smallest leaf and storage reserves of the three seagrasses under observation and is the only variety of the three that can also be found off the southwest coast.

In the second stage of the research, the plants were subjected to fine sediment (Rocla Quarries WA sponsored UWA with high-grade fine sediments) burial at a depth of between 4mm to 70mm but the effects of light were found to have a far greater impact.

“Only the deepest burial treatments resulted in in some adverse effects,” Dr Statton said. “The seagrasses adapted and grew vertically to new sediment heights then, much like suburban lawns, they put out runners spreading across the new sediment surface. So their initial response to being buried in sediment was to increase the length of their leaves then grow vertically.”

The next step to the lab work will be to install the combined sediment burial and light interaction experiment to look at answering the questions as to what synergies there are when the stresses are combined.

 

The first part of this story was published in the February WAMSI Bulletin:

WAMSI research finds northwest seagrass in a world of its own (Part 1 – in the field)

Related Links:

Tropical Seagrass examined for light pressures (article by Science Network WA)

 

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.

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Dredging Science

What is the Kimberley worth?

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With her 11-month old baby in tow, Dr Jennifer Strickland-Munro spent five months camping along the 13,000km stretch that marks the Kimberley coastline to find out exactly how people value the area and what their hopes are for its future.

The 2013 trek with her son, Samson and husband, Beau, from Darwin to Eighty Mile Beach, has culminated in the first report from the “Values and aspirations for coastal waters of the Kimberley” research project funded by the Western Australian Government and administered by WAMSI.

In the first study of its kind to document the extent to which the region’s ~35,000 residents and many tourists value the Kimberley coast and marine environment, the results demonstrate that despite how hard it is to access some areas, there is nowhere that is considered without value.

Jennifer interviewing a Kimberley resident

“We interviewed 232 people in total that we met along the way, from a range of stakeholder groups,” Dr Strickland-Munro said. “This included Aboriginal Traditional Owners, Aboriginal and non-Aboriginal residents, people from recreational and commercial fishing interests, aquaculture, tourists and tour operators, marine transport, Federal, State and local government, environmental non-government organisations and a range of community groups like sea rescue clubs who are clearly out and about on the coast.”

“Analysis of interview data revealed that social values for the Kimberley coastline and marine environment are largely non-consumptive, direct uses. Values relating to the physical landscape (e.g. aesthetics, coastal geology, unique nature experiences, and the Kimberley’s ‘pristine untouched environment’) were dominant.

“Biodiversity, an indirect use value relating to the presence of key flora and fauna including marine animals, reef biodiversity, migratory shorebirds and mangroves, was also widely and intensely valued,” Dr Strickland-Munro said.

A broad suite of Aboriginal values also emerged, with the clear need to include Aboriginal people in decision making rating highly.

Jennifer and family camping in the Kimberley

The project is now moving into its next phase as it looks to extend and validate what has already been found. An online survey will be launched in early April. The survey uses Public Participation GIS (PPGIS) techniques in which people place markers onto a Google map interface to indicate where and what they value about the Kimberley coast, as well as their management preferences for the future.

For more information about the survey contact Jennifer at j.strickland-munro@murdoch.edu.au.

The results of the three year project will be available by the end of the year when the newly documented information will be able to be put into practice across planning for parks and wildlife, shires and industry to help better understand the suite of values and aspirations for the Kimberley coast.

 

[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.]

 

Attached files:

PDF iconvalues_and_aspirations_for_coastal_waters_of_the_Kimberley.pdf

Category:

Kimberley Marine Research Program

Fears sea levels could rise as scientists find signs huge Antarctic glacier is melting

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New aerial ice studies have given scientists an unprecedented insight into how one of the world’s largest glaciers is melting.

The research, published in the journal Nature Geoscience, has uncovered a series of tunnels and gateways which are allowing warm water to eat away at the Totten Glacier in East Antarctica, potentially leading to a dramatic rise in global sea levels.

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WAMSI Research Conference 2015

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Category: 

Research Conference 2015

Premier launches Marine Science Blueprint at WAMSI conference

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Western Australian Premier and Minister for Science Hon. Colin Barnett MLA launched the WA Blueprint for Marine Science 2050 at the Western Australian Marine Science Institution (WAMSI) research conference (30 March-1 April).

The Blueprint is an important initiative that aims to help government, research institutions and industry to better plan and collaborate on the priority marine research needed to support the future prosperity of WA and the nation.

The recommendations are the culmination of comprehensive consultation focusing on the end users of research, business, industry, government and community groups brought together by an independent steering group led by renowned scientist and advocate for collaborative research, E/Prof Alistar Robertson.     

Premier Barnett, Professor Robertson and WAMSI CEO Patrick Seares launched the Blueprint on Wednesday 1st April 2015 at 1.30pm at the WAMSI Conference held at the State Library.

WAMSI Conference 

The 2015 research conference has provided progress updates and latest findings from more than 50 WAMSI projects being delivered by its partner organisations forming part of two of the largest marine research programs in Australia.

Among the keynote speakers;

  • EPA Chairman Paul Vogel will discuss science, knowledge and managing risk through environmental impact assessment;
  • Woodside Energy, Senior Vice President Science and Technology, Shaun Gregory, will provide an industry perspective on strategic marine science;
  • WA Chief Scientist Peter Klinken will present his views on the State’s research focus; and
  • WAMSI CEO Patrick Seares will present an overview of research progress, future direction and initiatives to improve collaboration on information.

Over the course of the three day conference, lead researchers and industry representatives who are working with WAMSI on the Kimberley Marine Research Program and the Dredging Science Node provided updates on the foundational research supporting these programs including:

  • Reports on the most up to date information available for use in dredging operations and management, including lessons learned from the Gorgon Dredging Project at Barrow Island and its application to the management of the Wheatstone Dredging Project at Onslow; and 
  • Key findings and future direction for marine research being carried out for the first time in the unique conditions that exist off the Kimberley coast.  

WAMSI Conference 2015

Location:        The State Library of Western Australia

         Perth Cultural Centre, 25 Francis Street, Perth

Date:              Monday 30 March – Wednesday 1 April 2015.

Click here to view the full conference schedule (as at 26/02/2015)

More information including conference schedule updates, abstracts and audio/PowerPoint presentations are available on the WAMSI Conference 2015 webpage.    

 

Category: 

Research Conference 2015 Kimberley Marine Research Program Dredging Science

The Kimberley coastline: what lies beneath?

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The ocean bottom supports communities as diverse as those of any habitat on land but learning about what lies beneath the sea off Australia’s remote and hazardous Kimberley coast is presenting many challenges for marine scientists.

One project, which aims to explore and describe the nature of seabed life in the far northwest, is beginning to reveal the diverse nature of life beneath the sometimes swirling, turbid waters.

The results will form the basis for sound decision making to support conservation and sustainable development of marine parks as part of the Western Australian Marine Science Institution’s (WAMSI) Kimberley Marine Research Program.

Project leader, The Australian Institute of Marine Science’s (AIMS) Dr Andrew Heyward explained how the researchers are collecting data where ships carrying scientists and a range of equipment will survey the seabed areas in the southern, central and northern Kimberley.

“This work is the major field activity for the project and consists of five expeditions over the next couple of years. The first, undertaken last November, focussed on mapping the very large area contained within the boundaries of the recently declared Lalang -garram/Camden Sound Marine Park.”

“We mainly used acoustic mapping of depth and seabed shape using multibeam echo sounders combined with direct assessment of habitats on the seabed using towed video cameras,” Dr Heyward said.

Along with researchers from CSIRO and the WA Museum, the scientists will also work with Indigenous groups of the Kimberley coasts, including the sea rangers, who will provide additional information about shallow near shore areas.

“The initial survey has revealed very complex seabed shapes in some places, particularly close to island edges and narrow channels, where the extreme tides caused strong currents,” Dr Heyward said. “In those places the seabed was fairly hard, being either exposed rocky ground or pavement with a veneer of coarse sand.

Those sorts of places often supported low to medium density patches of filter feeding organisms like sponges and sea fans.”

High resolution photos also revealed very diverse life was often present on submerged rocks and ledges, but many of the organisms were small or encrusting. The researchers anticipate that many new species, both large and small, will be discovered once samples are identified back at the WA Museum.

In the northern part of the Lalang -garram/ Camden Sound Marine Park, an archipelago of islands provides a range of different habitats, including fringing reefs where, at low tide, abundant areas of coral can be seen exposed on the edges of the reef flats.

In contrast the deeper and more open bay areas of Camden Sound typically had fewer exposed rocky areas of seabed, but were frequently large areas of sand, including in a few places, large underwater sand dunes formed by the strong tidal currents.

“So the large open part of the Lalang -garram/Camden Sound zoned for whale sanctuary, is kind of like a big sandpit for them to frolic in,” Dr Heyward said.

Mixed brozoans soft corals sponges & seafans on rock

The researchers found that during spring the tidal currents caused increased turbidity, making camera work very challenging. The turbid water also greatly reduced the amount of light reaching the seabed.

“When we measured this it was quite common for little or no light to reach below depths of 10-15m below low tide,” Dr Heyward said. “This observation explains why organisms that rely on light for growth were not found in the broader parts of the bay which were typically 20-40m deep. So things like seaweeds and reef building corals tend to be close to the edges on hard rocky ground that is not too deep.”

A second expedition back to Camden Sound will commence this March. While further mapping of the seabed will continue, that expedition will also allow the scientists from AIMS, CSIRO and WA Museum, to collect samples of the biota. These samples will form the basis of the Kimberley project’s biodiversity reference collection at the WA Museum.

 

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

WAMSI research finds northwest seagrass in a world of its own

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Groundbreaking research into the sensitivity of seagrasses off the northwest coast has uncovered unique behaviour that could lead to a re-think in the way the region is managed.

The seagrasses off Western Australia are the most extensive and diverse of any region in the world with 26 species in 11 genera, accounting for more than 35 per cent of all species currently described globally.

The submerged flowering plants play a vital role in supporting biodiversity, filtering harmful chemicals and nutrients, and sequestering CO2 from the atmosphere. Tropical seagrasses are also a critical food source for fauna such as dugong and green turtles, but little is known about populations off the subtropical northwest .

A Western Australian Marine Science Institution (WAMSI) Dredging Science Node project has brought together researchers from Edith Cowan University (ECU), The University of Western Australia (UWA) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to measure the effects of light reduction and sediment burial to determine the capacity for northwest seagrasses to withstand change.

Tolerance levels have previously been determined for seagrasses in the southwest but they are very different to the species off the far northwest coast according to ECU Professor Paul Lavery.

“In the southwest, the dominant species of seagrasses have large storage organs and carbon reserves, and produce large non-dormant seeds,” Professor Lavery said. “Because of their considerable carbon reserves, when they are placed under stress by dredging operations, they draw on those carbon reserves and can survive for several months.

James McLouglin and Roisin McCallum establish a field experiment at Thevenard Is. to determine the mechanisms and rate of seagrass recovery
James McLouglin and Roisin McCallum establish
a field experiment at Thevenard Is. to determine
the mechanisms and rate of seagrass recover

“The seagrass species up north are much smaller, producing small dormant seeds that lay waiting in sediments. They appear to be much more sensitive to changes in light and sediment cover. However we need to be cautious,” he said. “While they may show a rapid response to dredging-induced changes, we don’t really understand yet if they can recover quickly from those impacts. It’s possible that a few months after complete loss, the meadow returns from seed.”

The researchers are conducting a combination of field studies and controlled laboratory experiments.

“We’re working in the Pilbara areas around Exmouth Gulf and Thevenard Island (about 20km off Onslow),” Professor Lavery said. “We’ve been going up every few months to measure characteristics of the meadows, from when they grow, to when they die off and how much biomass there is. This is information we just don’t have for seagrasses in the north.”

Northern sites_Mick Haywood
Research sites in the Pilbara areas around Exmouth Gulf and Thevenard Island

The research program is focused on gaining information that is useful and relevant in a systematic way. An initial recommendation from the research is that pre-development surveys and ongoing monitoring programs for seagrass should consider the time of year. In the month of June, for example, there appears to be no seagrass meadows. It’s not until September that they start to grow back.

“This most basic and fundamental piece of information we didn’t understand before,” Professor Lavery said. “This in turn will save money for companies as they often conduct costly surveys when seagrass is not naturally present.”

We’ve now conducted field studies in several locations to see if the same sort of patterns exist in each location and so far we’re finding that different places have different patterns, which makes things more complicated and is going to make advising government and industry more challenging.”

Off Thevenard Island the researchers removed seagrasses from both shallow and deep water meadows to observe how the system recovers.

“We wanted to see if the meadows can recover from seed or by material drifting in from elsewhere,” Professor Lavery said. “So far we aren’t seeing any recovery by seed. There seems to be a need to have vegetative material available for it to grow back. So it’s back to the lab now to find out the capacity for the seagrasses to withstand change.”

 

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

Seagrass helps protect natural ‘carbon sinks’, study finds

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The disappearance of seagrass meadows could be contributing to greenhouse gas emissions, an international study has found.

As ABC online reports, research conducted at Oyster Harbour in Albany found centuries-old carbon dioxide deposits have been created by seagrass meadows.

Scientists at The University of Western Australia’s Oceans Institute, in conjunction with overseas researchers, discovered the meadows act as carbon “sinks”, preventing the erosion of carbon deposits and the subsequent release of carbon dioxide into the atmosphere.

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Going with the flow in the Kimberley

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A Western Australian Marine Science Institution (WAMSI) project is using genetics to see how ocean currents in the Kimberley transport marine organisms from one reef to another.

Bardi-Jawi rangers, Mayala traditional owners and researchers from four WAMSI partner institutions recently conducted field studies along the remote and rugged coastline, collecting samples on exposed reefs at low tide between the 12 metre tidal surges around the Dampier Peninsular and Buccaneer Archipelago.

“We collected seagrasses, corals, fishes and trochus shells that live in the intertidal zone which is exposed at low tide,” CSIRO’s Dr. Oliver Berry said.

“We selected these species to represent the types of organisms that are common in the Kimberley. Some are also commercially, recreationally or culturally important like the trochus shell and stripey snapper, or form key habitats like seagrass and corals.”

Sites sampled Dampier Peninsular and Buccaneer Archipelago

Sites sampled Dampier Peninsular and Buccaneer Archipelago

 

The researchers are using scans of the organisms’ genomes to measure the genetic relationships between different reefs and seagrass beds. The more genetically similar the organisms from different reefs are, the more movement occurs between them.

“When you consider managing a marine resource you have to understand what drives population dynamics,” Dr. Berry said. “For some populations whether they are growing or shrinking is driven locally by births and deaths. But, especially in places where there are strong tides and currents, it’s possible that even populations quite distant from each other are strongly interdependent because organisms move between them a lot.”

“A seemingly large area like the Kimberley can be very linked if hydrodynamics (ocean currents) drive those population linkages. So if there was a disaster at one location, if that population was insular, or locally driven, it may take a long time for it to recover. But if the population was linked to other areas then it may recover more rapidly. What we’re trying to do is to better understand these relationships between populations.

“Of course it’s a difficult thing to study because most movement in marine species occurs when they are tiny eggs, seeds, or larvae. Genetics is a way to indirectly measure movement, and it’s becoming increasingly cost-effective and powerful with the development of genome sequencing technologies,” Dr. Berry said.

The research being undertaken by WAMSI with scientists from Edith Cowan University, AIMS, Department of Fisheries, WA and the Western Australian Museum, is expected to uncover a range of different patterns reflecting the exposure to currents of different reefs and the different life histories of the organisms.

“For example, looking at the patterns in the trochus shell, we know it has a short larval stage and that some fishes have longer ones,” Dr Berry said. “We expect this to mean fish get transported further and that these differences will be reflected in the genetic relationships between populations.”

“This is the first time anyone has attempted anything like this in the Kimberley, and anywhere in the world in such a macro-tidal environment,” he said.

“Now that there is increasing interest in developing the region we need to get a baseline understanding of how the ecosystem works, so that it can be managed effectively,” Dr Berry said. “We expect to have some results by the end of this year.”

 

[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