Signals from the sawfish nursery

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By Jeff Whitty and Dr David Morgan

Murdoch University’s Freshwater Fish Group (Centre for Fish & Fisheries Research) in conjunction with the Nyikina-Mangala Rangers, are unravelling the mysteries of one of the most threatened fishes in the world, the freshwater sawfish (Pristis pristis).

A WAMSI project funded by Chevron Australia, ‘Team Sawfish’ is helping to protect one of the world’s largest fishes that is found in freshwater. The freshwater sawfish has declined globally, and in Australia is listed as Vulnerable on the Environment Protection and Biodiversity Conservation (EPBC) Act.

Facing multiple threats including fishing pressure, often by means of bycatch and habitat modification, the numbers and ranges of all sawfishes have greatly declined. In Western Australia, the freshwater sawfish inhabits rivers as juveniles and as such it is likely to be impacted by habitat modifications such as instream barriers (e.g. dams), which may obstruct their migrations into freshwater nurseries. Murdoch University researchers are investigating what impacts these barriers may have on the freshwater sawfish.

In August 2015, Team Sawfish, consisting of Murdoch University researchers and the local Nyikina-Mangala Rangers, set out to continue their work studying the impacts of such barriers in the Fitzroy River, Western Australia.
Team Sawfish measuring a freshwater sawfish

Starting at 360rkm (i.e. 360 kilometres upstream of the river mouth), Team Sawfish systematically sampled pools for sawfish as they moved downstream, including those pools located in close proximity to  the various barriers on the river and ending within the estuarine pools near the river mouth.

The aim of this trip was to catch and tag freshwater sawfish with acoustic transmitters in order to monitor and thus better understand how anthropogenic barriers may affect the movements and/or behaviour of these fishes during the wet and dry seasons, noting movement over the barriers is only possible during peak flows during the wet season (December-April).
Nyikina-Mangala Rangers preparing to deploy an acoustic receiver to monitor the movements of tagged sawfish

During their sampling efforts, Team Sawfish found pools along the river to have become filled in and shallow, a likely result of the lack of flushing of introduced sediments during the past few small wet seasons.

The small 2014-2015 wet season also seemed to have led to the capture/presence of very few sawfish and no young of the year (those pupped within the 2014-2015 wet season).

This finding was congruent with findings from previous years, which suggested that the relative abundance of sawfish within the freshwater pools of the river is positively correlated with the size of the previous wet season.  

The Freshwater Sawfish that were captured were limited to size classes that would have been pupped in 2011-2012. Observing sawfish from the 2011 year class to still be present within the river provided further evidence that some juvenile sawfish do inhabit the river for more than four years, as previous data suggested.

The monitoring of sawfish continues and the team is continuing to tag and record freshwater sawfish in spring of this year.

If you catch a tagged sawfish, or would like to know more about these mysterious creatures, please contact fish@murdoch.edu.au.

 

Category: 

Sawfish Project

IGEM collaboration important first step in voluntary industry data sharing

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The success of a pilot project that generated a snapshot of environmental data relevant to impact assessment and monitoring off the northwest coast is on track to begin sharing industry meta-data from the many industry funded studies in Western Australia.

Several conscientious oil and gas companies have taken the initiative by agreeing to share information about the huge number of datasets they collect.

Woodside, Chevron, Inpex, Murphy Oil Australia, PTTEP, Quadrant Energy (formally Apache), Santos, Shell Australia, facilitated by their peak industry body APPEA, are creating a meta-database called the Industry-Government Environmental Meta-database (IGEM), which is being developed and operated by the Western Australian Marine Science Institution (WAMSI).   

Metadata is information about data. It tells you where, how, when and what data was collected.  As well as these companies, WAMSI, the Australian Institute of Marine Science and the state government Departments of Parks and Wildlife, and Fisheries are also contributing their own metadata to the IGEM.

“As an industry, we collect a huge amount of data,” Chair of the APPEA Environment and Safety Committee Gerry Flaherty said. “But right now only the companies who pay for the projects know what has been collected.  If we have an emergency we need to respond to quickly. Having a place where everyone can see what information is out there will dramatically improve our response.”

“This will be a great advantage for IGEM partners in projects to inform regulatory processes or for research purposes, not just response,” WAMSI CEO Patrick Seares said. “It means they can look at the IGEM to see what already exists, then negotiate access to it with the owners rather than doing expensive duplicate fieldwork.”

IGEM will have the capacity to increase its key datasets but it will begin with using metadata collected post-2008 in seven key areas: mangroves; benthic habitats; demersal fish, nesting turtles, seabirds and shorebirds, megafauna; and sediment quality.

Subscribers will be able to search for relevant environmental studies by research activity in a specific area; the date it was collected; the organisation that collected the data; type of data; and key words.

The in-development web-based platform should initially provide access to geospatial metadata records on key studies off Western Australia, but with the potential to expand nationally. The site will have a page accessible to the general public with limited information and a log-in interface for approved members who can generate reports.

“I hope as we can start seeing the system evolve that other companies, agencies and research groups see the positives in this process and follow the lead of the current participants,” Patrick Seares said. “Sharing metadata has so many upsides and really doesn’t expose the data owners to any risk.”

The IGEM platform is expected to be available by early 2016.

Field report from research vessels in Camden Sound, Kimberley region

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The initial ship-based expedition to Camden Sound was conducted under the auspices of WAMSI’s Kimberley Benthic Biodiversity Project, which aims to provide a better knowledge base about what occurs where in the Kimberley’s diverse marine environments, especially in areas of management priority such as the state government’s proposed marine parks and reserves.

Cruise leader on board the RV Solander, Dr Andrew Heyward from AIMS in Perth, said that the vessel operated 24/7 during its 18-day itinerary. “Scientists and staff worked in shifts, doing towed video and sediment sampling during daylight, and multibeam sonar surveys during the night,” he said.

Although the weather was generally very good, extreme tides, strong currents, turbid waters and some uncharted areas provided plenty of challenges for researchers. They successfully completed more than 200 km of towed video and thousands of km of multibeam seafloor mapping, in the first of two expeditions to the Camden Sound area.

“We’ve seen large areas of dynamic sand across the open Sound, including some patches with underwater sand dunes,” commented Andrew, “but also rocky ground covered in a large variety of marine invertebrates, in particular sponges and soft corals.”

The turbid waters of Camden Sound prevent sunlight from penetrating more than ~10 m in depth, so organisms that need light – such as corals and seaweeds – appear to be restricted to the shallowest parts of rocky ground and the upper edges of fringing reefs around islands. As depth increases and light fades the filter feeding sponges, soft corals, ascidians and bryozoans become the dominant components of the seabed communities.

“Thanks to the combined efforts of the Solander and the Linnaeus this month,” said Andrew, “we’re beginning to understand a lot more about what the seafloor of the Lalang-garram-Camden Sound Marine Reserve looks like, and the benthic biodiversity that lives there.”

Dr Iain Parnum from Curtin University is busily compiling all the gathered multibeam sonar data now. “In terms of outputs, first of all, we’ll deliver some much-needed improved bathymetry information for Camden Sound,” he explained. “Secondly, sonar backscatter data – both from the seafloor and the water column – will give us good insights into the kinds of underwater terrain and ecosystems at each sampled location.”

In addition, Dr John Keesing from CSIRO took advantage of the presence of the RV Solander in the Kimberley to advance another WAMSI project investigating historic changes in water quality. He collected sediment cores (each ~1.5 m long) at ~20 m depth from two locations in Roebuck Bay. “These cores will be used to reconstruct a time series of water quality in the Bay, which is expected to go back about 100 years,” he said.

As with all WAMSI projects, the data and outputs will be freely available to everyone with an interest in the marine environments of the Kimberley.

Map showing sites in Camden Sound where towed video surveys were conducted in November 2014 

 

A still image from one of the towed video surveys showing mixed filter-feeding community (including bryozoans, sponges and soft corals) growing on a rock outcrop (Photo courtesy of AIMS)

Category:

Kimberley Marine Research Program

Vale Professor Lindsay Collins

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We are deeply saddened to hear of the passing of Professor Lindsay Collins.

Lindsay has been involved with WAMSI since its inception in 2006. A leading geomorphologist with the Applied Sedimentology and Marine Geoscience Group, Department of Geology at Curtin University, he was a valued friend and project leader on both the Ningaloo Research Program in collaboration with CSIRO and the WA Museum, WAMSI’s Caring for our Country Project – Shark Bay and the current Kimberley Marine Research Program.

Lindsay was one of life’s true gentlemen and we all owe him a debt of gratitude for his dedication and lasting contribution to marine science.

He shared his passion for geomorphology supervising some 50 Honours, Masters and PhD geoscience students over his more than 40 years of research and teaching during which time he earned the respect of his colleagues as a highly cited scientist and an expert in his field.

Lindsay Collins could always be relied on to produce high quality, successful and valuable collaborative projects. Just this year we were fortunate to have him present his latest project for us on Kimberley Reef Growth and Maintenance at the WAMSI Conference in March.

Lindsay’s wise guidance about science, but also people, has always been highly valued by WAMSI. His engaging personality and honest opinion were a great asset to the marine science community as a whole.

On behalf of all of us at the Western Australian Marine Science Institution and its partners I offer our sincere condolences to his family, and his many colleagues.

Patrick Seares
WAMSI CEO
 

The funeral for Professor Lindsay Collins will take place next Friday, 11th September at 2.30 at Karrakatta Cemetery, followed by a wake at Cottesloe Beach Hotel at 4.30pm.

Lindsay Collins and Premier Colin Barnett at the 2015 WAMSI Conference