With no work in lockdown, tour operators helped find coral bleaching on Western Australia’s remote reefs



Jeremy Tucker, Author provided

James Paton Gilmour, Australian Institute of Marine Science

Significant coral bleaching at one of Western Australia’s healthiest coral reefs was found during a survey carried out in April and May.

The survey took a combined effort of several organisations, together with tour operators more used to taking tourists, but with time spare during the coronavirus lockdown.

WA’s arid and remote setting means many reefs there have escaped some of the pressures affecting parts of the east coast’s Great Barrier Reef), such as degraded water quality and outbreaks of crown of thorns starfish.

The lack of these local pressures reflects, in part, a sound investment by governments and communities into reef management. But climate change is now overwhelming these efforts on even our most remote coral reefs.

Significant coral bleaching has been identified at WA reefs.
Nick Thake, Author provided

When the oceans warmed

This year, we’ve seen reefs impacted by the relentless spread of heat stress across the world’s oceans.

As the 2020 mass bleaching unfolded across the Great Barrier Reef, a vast area of the WA coastline was bathed in hot water through summer and autumn. Heat stress at many WA reefs hovered around bleaching thresholds for weeks, but those in the far northwest were worst affected.

The remoteness of the region and shutdowns due to COVID-19 made it difficult to confirm which reefs had bleached, and how badly. But through these extraordinary times, a regional network of collaborators managed to access even our most remote coral reefs to provide some answers.




Read more:
We just spent two weeks surveying the Great Barrier Reef. What we saw was an utter tragedy


Australia’s Bureau of Meteorology provided regional estimates of heat stress, from which coral bleaching was predicted and surveys targeted.

At reefs along the Kimberley coastline, bleaching was confirmed by WA’s Department of Biodiversity, Conservation and Attractions (DBCA), Bardi Jawi Indigenous rangers, the Kimberley Marine Research Centre and tourist operators.

At remote oceanic reefs hundreds of kilometres from the coastline, bleaching was confirmed in aerial footage provided by Australian Border Force.

Subsequent surveys were conducted by local tourist operators, with no tourists through COVID-19 shutdown and eager to check the condition of reefs they’ve been visiting for many years.

The first confirmation of bleaching on remote coral atolls at Ashmore Reef and the Rowley Shoals was provided in aerial images captured by Australian Border Force.
Australian Border Force, Author provided

The Rowley Shoals

Within just a few days, a tourist vessel chartered by the North West Shoals to Shore Research Program, with local operators and a DBCA officer, departed from Broome for the Rowley Shoals. These three reef atolls span 100km near the edge of the continental shelf, about 260km west-north-west offshore.

One of only two reef systems in WA with high and stable coral cover in the last decade, the Rowley Shoals is a reminder of beauty and value of healthy, well managed coral reefs.

But the in-water surveys and resulting footage confirmed the Rowley Shoals has experienced its worst bleaching event on record.

The most recent heatwave has caused widespread bleaching at the Rowley Shoals, which had previously escaped the worst of the regional heat stress.
Jeremy Tucker, Author provided

All parts of the reef and groups of corals were affected; most sites had between 10% and 30% of their corals bleached. Some sites had more than 60% bleaching and others less than 10%.

The heat stress also caused bleaching at Ashmore Reef, Scott Reef and some parts of the inshore Kimberley and Pilbara regions, all of which were badly affected during the 2016/17 global bleaching event.

This most recent event (2019/20) is significant because of the extent and duration of heat stress. It’s also notable because it occurred outside the extreme El Niño–Southern Oscillation phases – warming or cooling of the ocean’s surface that has damaged the northern and southern reefs in the past.

A reef crisis

The impacts from climate change are not restricted to WA or the Great Barrier Reef – a similar scenario is playing out on reefs around the world, including those already degraded by local pressures.

By global standards, WA still has healthy coral reefs. They provide a critical reminder of what reefs offer in terms of natural beauty, jobs and income from fisheries and tourism.

Despite the most recent bleaching, the Rowley Shoals remains a relatively healthy reef system by global standards. But like all reefs, its future is uncertain under climate change.
James Gilmour, Author provided

But we’ve spent two decades following the trajectories of some of WA’s most remote coral reefs. We’ve seen how climate change and coral bleaching can devastate entire reef systems, killing most corals and dramatically altering associated communities of plants and animals.

And we’ve seen the same reefs recover over just one or two decades, only to again be devastated by mass bleaching – this time with little chance of a full recovery in the future climate.

Ongoing climate change will bring more severe cyclones and mass bleaching, the two most significant disturbances to our coral reefs, plus additional pressures such as ocean acidification.

Reducing greenhouse gas emissions is the only way to alleviate these pressures. In the meantime, scientists will work to slow the rate of coral reef degradation though new collaborations, and innovative, rigorous approaches to reef management.The Conversation

James Paton Gilmour, Research Scientist: Coral Ecology, Australian Institute of Marine Science

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How we discovered the conditions behind ‘slow earthquakes’ that happen over weeks or even months – new research


The world’s tectonic plates.
Naeblys/Shutterstock

Åke Fagereng, Cardiff University

You’re probably familiar with earthquakes as relatively short, sharp shocks that can shake the ground, topple buildings and tear rips in the Earth. These earthquakes, and their aftershocks, happen because although tectonic plates move at centimetres per year, this motion is seldom steady. Earthquakes result from a “stick-slip” motion, where rocks “stick” along fault planes while stress accumulates until a “slip” occurs – a bit like pulling on a stuck door until it suddenly opens. This slip also releases energy as the seismic waves that, in large magnitude earthquakes, create substantial damage.

In the last two decades another class of stick-slip motion has been discovered worldwide. These “slow slip events” last for weeks to months, compared to seconds to minutes for earthquakes. Slow slip events occur faster than average plate motion, but too slow to generate measurable seismic waves. This means they need to be studied by GPS networks rather then seismometers.

Although their motion is slow, the amount of movement that occurs in a slow slip event is substantial. Earthquake magnitude depends on the distance that rocks move and the area this movement occurs over. Using the same definition, many slow slip events would have had magnitudes above 7.0 if they slipped at earthquake speeds.

Slow slip events repeat at intervals of a year to a few years. Compared to major earthquakes, which have repeat times of hundreds of years (or more), slow slip events are actually very frequent. Even in the short time of a couple of decades that we’ve observed these types of slip, many cycles have occurred in several places – notably around the Pacific Rim.

Slow slip events generally happen next to areas where faults are locked and expected to rupture in major earthquakes. It’s therefore possible that these slow slip events can trigger earthquakes on neighbouring locked faults. It has, for example, been suggested that slow slip events preceded the 2011 magnitude 9.1 Tohoku earthquake in Japan and the 2014 magnitude 8.1 Iquique earthquake in Chile. That said, numerous slow slip events have also been observed without any immediate, subsequent major earthquakes on neighbouring faults.

Earthquakes may also trigger slow slip. In particular, the magnitude 7.8 Kaikōura earthquake in New Zealand in 2016 triggered slow slip events up to 600km away from its epicentre.

It is not known why some fault segments host slow slip and others host earthquakes. Neither is it known whether the same area can change behaviour and host either slow slip or earthquakes at different times. It’s therefore important to characterise the source of slow slip, and find out what materials help create slow slip and under what conditions.

A unique opportunity

The Hikurangi subduction zone.
Åke Fagereng composite using map data from NOAA., Author provided

The Hikurangi subduction zone (where the Pacific ocean floor is pulled underneath the New Zealand continent) offshore New Zealand’s North Island is potentially the country’s largest earthquake fault and is a unique opportunity to investigate slow slip events. This is because slow slip here happens shallower and closer to the shoreline than anywhere else in the world.

The drill.
Åke Fagereng, Author provided

The shallow slow slip events in New Zealand have been observed by onshore GPS and ocean bottom pressure sensors. Oceanic scientific drilling expeditions recently sampled sediments and installed observatories along this margin.

The subduction zone.
Stihii/Shutterstock

These International Ocean Discovery Program expeditions – which drilled to just over 1km deep in water depths of 3.5km in late 2017 and early 2018 – revealed that the seafloor rocks and sediments hosting slow slip in Hikurangi are extremely variable. The range of rocks, described in a recent Science Advances paper led by Philip Barnes of NIWA (New Zealand’s National Institute of Water and Atmospheric Research), include mudstones, sands, carbonates, and sedimentary deposits from oceanic volcanic eruptions. The seafloor samples show that the source of the slow slip is a mixture of very soft sediment and hard, solid rocks.

Different types of rock from the New Zealand seafloor.
Åke Fagereng, Author provided

The diverse seafloor sediments are not the only variability offshore of New Zealand. The seafloor itself is also very rough, including seamounts (submarine mountains rising over a kilometre above the seafloor). This seafloor roughness also makes the fault vary depending on where along it you are.

The observations are consistent with a hypothesis where slow slip events occur in rocks that are transitional between moving steadily and moving in earthquakes. One way to think of this model is as rigid rocks interacting with softer, more ductile surroundings. Researchers using numerical simulations and laboratory experiments have also suggested that variable fault rocks can cause slow slip.

But diverse fault rock isn’t the only model for the mechanics of slow slip. Another possibility is that pressurised fluids decrease frictional resistance and slip speed along faults. It is also possible that some rocks become stronger when they move faster – so that faults start accelerating but slow down before reaching earthquake speeds.

The recent discoveries in New Zealand may be applicable to other depths and locations around the world. However, future studies will undoubtedly lead to further insights and complexities – including in the relationship between slow slip events and earthquakes.The Conversation

Åke Fagereng, Reader, School of Earth and Ocean Sciences, Cardiff University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We’ve just discovered two new shark species – but they may already be threatened by fishing



One of the newly discovered sixgilled sawshark species (Pliotrema kajae).
Simon Weigmann, Author provided

Per Berggren, Newcastle University and Andrew Temple, Newcastle University

Finding a species that’s entirely new to science is always exciting, and so we were delighted to be a part of the discovery of two new sixgill sawsharks (called Pliotrema kajae and Pliotrema annae) off the coast of East Africa.

We know very little about sawsharks. Until now, only one sixgill species (Pliotrema warreni) was recognised. But we know sawsharks are carnivores, living on a diet of fish, crustaceans and squid. They use their serrated snouts to kill their prey and, with quick side-to-side slashes, break them up into bite-sized chunks.

The serrated snout of a sixgill sawshark (Pliotrema annae).
Ellen Barrowclift-Mahon/Marine MEGAfauna Lab/Newcastle University., Author provided

Sawsharks look similar to sawfish (which are actually rays), but they are much smaller. Sawsharks grow to around 1.5 metres in length, compared to 7 metres for a sawfish and they also have barbels (fish “whiskers”), which sawfish lack. Sawsharks have gills on the side of their heads, whereas sawfish have them on the underside of their bodies.

A sixgill sawshark (Pliotrema annae) turned on its side, showing gills and barbels.
Ellen Barrowclift-Mahon, Author provided

Together with our colleagues, we discovered these two new sawsharks while researching small-scale fisheries that were operating off the coasts of Madagascar and Zanzibar. While the discovery of these extraordinary and interesting sharks is a wonder in itself, it also highlights how much is still unknown about biodiversity in coastal waters around the world, and how vulnerable it may be to poorly monitored and managed fisheries.

The three known species of sixgill sawshark. The two new species flank the original known species. From left to right: Pliotrema kajae, Pliotrema warreni (juvenile female) and Pliotrema annae (presumed adult female).
Simon Weigmann, Author provided

Fishing in the dark

Despite what their name might suggest, small-scale fisheries employ around 95% of the world’s fishers and are an incredibly important source of food and money, particularly in tropical developing countries. These fisheries usually operate close to the coast in some of the world’s most important biodiversity hotspots, such as coral reefs, mangrove forests and seagrass beds.

For most small-scale fisheries, there is very little information available about their fishing effort – that is, how many fishers there are, and where, when and how they fish, as well as exactly what they catch. Without this, it’s very difficult for governments to develop management programmes that can ensure sustainable fishing and protect the ecosystems and livelihoods of the fishers and the communities that depend on them.

Small-scale fishers of Zanzibar attending their driftnets.
Per Berggren/Marine MEGAfauna Lab/Newcastle University, Author provided

While the small-scale fisheries of East Africa and the nearby islands are not well documented, we do know that there are at least half a million small-scale fishers using upwards of 150,000 boats. That’s a lot of fishing. While each fisher and boat may not catch that many fish each day, with so many operating, it really starts to add up. Many use nets – either driftnets floating at the surface or gillnets, which are anchored close to the sea floor. Both are cheap but not very selective with what they catch. Some use longlines, which are effective at catching big fish, including sharks and rays.




Read more:
Sharks: one in four habitats in remote open ocean threatened by longline fishing


In 2019, our team reported that catch records were massively underreporting the number of sharks and rays caught in East Africa and the nearby islands. With the discovery of two new species here – a global hotspot for shark and ray biodiversity – the need to properly assess the impact of small-scale fisheries on marine life is even more urgent.

Pliotrema kajae, as it might look swimming in the subtropical waters of the western Indian Ocean.
Simon Weigmann, Author provided

How many other unidentified sharks and other species are commonly caught in these fisheries? There is a real risk of species going extinct before they’re even discovered.

Efforts to monitor and manage fisheries in this region, and globally, must be expanded to prevent biodiversity loss and to develop sustainable fisheries. There are simple methods available that can work on small boats where monitoring is currently absent, including using cameras to document what’s caught.

A selection of landed fish – including sharks, tuna and swordfish.
Per Berggren, Author provided

The discovery of two new sixgill sawsharks also demonstrates the value of scientists working with local communities. Without the participation of fishers we may never have found these animals. From simple assessments all the way through to developing methods to alter catches and manage fisheries, it’s our goal to make fisheries sustainable and preserve the long-term future of species like these sawsharks, the ecosystems they live in and the communities that rely on them for generations to come.The Conversation

Per Berggren, Marine MEGAfauna Lab, Newcastle University and Andrew Temple, Postdoctoral Research Associate in Marine Biology, Newcastle University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How we discovered a new species of orangutan in northern Sumatra



File 20171103 26472 gug2mh.jpg?ixlib=rb 1.1
The new species has a smaller head, and a distinctly ‘cinnamon’ colour compared with other orangutans.
Maxime Aliaga, Author provided

Colin Groves, Australian National University and Anton Nurcahyo, Australian National University

We have discovered a new species of orangutan – the third known species and the first new great ape to be described since the bonobo almost a century ago.

The new species, called the Tapanuli orangutan (Pongo tapanuliensis), has a smaller skull than the existing Bornean and Sumatran orangutans, but has larger canines.

As we and our colleagues report in the journal Current Biology, the new species is represented by an isolated population of fewer than 800 orangutans living at Batang Toru in northern Sumatra, Indonesia.

Orangutan populations in Sumatra and Borneo – the new species’ distribution is shown in yellow.
Curr. Biol.

Read more: The lengthy childhood of endangered orangutans is written in their teeth


The existence of a group of orangutans in this region was first reported back in 1939. But the Batang Toru orangutans were not rediscovered until 1997, and then confirmed in 2003. We set about carrying out further research to see whether this isolated group of orangutans was truly a unique species.

On the basis of genetic evidence, we have concluded that they are indeed distinct from both the other two known species of orangutan: Pongo abelii from further north in Sumatra, and Pongo pygmaeus from Borneo.

The Batang Toru orangutans have a curious mix of features. Mature males have cheek flanges similar to those of Bornean orangutans, but their slender build is more akin to Sumatran orangutans.

The hair colour is more cinnamon than the Bornean species, and the Batang Toru population also makes longer calls than other orangutans.

Making sure

To make completely sure, we needed more accurate comparisons of their body dimensions, or “morphology”. It was not until 2013 that the skeleton of an adult male became available, but since then one of us (Anton) has amassed some 500 skulls of the other two species, collected from 21 institutions, to allow for accurate comparisons.

Analyses have to be conducted at a similar developmental stage on male orangutan skulls, because they continue growing even when adult. Anton found 33 skulls of wild males that were suitable for comparison. Of 39 different measurement characteristics for the Batang Toru skull, 24 of them fall outside of the typical ranges of northern Sumatran and Bornean orangutans.

The new orangutans have smaller heads – but some impressive teeth.
Matthew G Nowak, Author provided

Overall the Batang Toru male has a smaller skull, but bigger canines. Combining the genetic, vocal, and morphological sources of evidence, we have confidently concluded that Batang Toru orangutan population is a newly discovered species – and one whose future is already under threat.

Under threat as soon as they’re discovered.
Maxime Aliaga, Author provided

Despite the heavy exploitation of the surrounding areas (hunting, habitat
alteration and other illegal activities), the communities surrounding the habitat of the Tapanuli orangutan still give us the opportunity to see and census the surviving population. Unfortunately, we believe that the population is fewer than 800 individuals.

Of the habitat itself, no more than 10 square km remains. Future development has been planned for that area, and about 15% of the orangutans’ habitat has non-protected forest status.


Read more: Orangutans need more than your well-meaning clicktivism


The discovery of the third orangutan in the 21st century gives us an understanding that the great apes have more diversity than we know, making it all the more important to conserve these various groups.

The ConversationWithout the strong support of, and participation from, the communities surrounding its habitat, the future of the Tapanuli orangutan will be uncertain. Government, researchers and conservation institutions must make a strong collaborative effort to make sure that this third orangutan will survive long after its discovery.

Colin Groves, Professor of Bioanthropology, Australian National University and Anton Nurcahyo, , Australian National University

This article was originally published on The Conversation. Read the original article.

Australia: Large Number of New Spider Species Discovered in Queensland


The link below is to an article reporting on the discovery of over 50 new species of spider in Queensland, Australia.

For more visit:
https://www.theguardian.com/environment/2017/apr/11/fifty-new-species-of-spider-discovered-in-far-north-australia

Argentina: Fluorescent Frog Discovered


The link below is to an article that reports on the discovery of a fluorescent frog in Argentina.

For more visit:
https://www.theguardian.com/world/2017/mar/14/worlds-first-fluorescent-frog-discovered-in-south-america

Some of the world’s strangest species could vanish before they’re discovered


Bill Laurance, James Cook University

Scientists have described around 1.5 million species on Earth – but how many are still out there to be discovered? This is one of the most heated debates in biology. Discounting microbes, plausible estimates range from about half a million to more than 50 million species of unknown animals, plants and fungi.

This biodiversity matters because it could be used to fight human diseases, produce new crops, and offer innovations to help solve the world’s problems.

Why is there so much uncertainty in the numbers? The biggest reason, I argue, is that a lot of biodiversity is surprisingly hard to find or identify. This has profound implications for nature conservation and for our understanding of life on Earth.

Hidden biodiversity

We find new species every day but the organisms that we’re now discovering are often more hidden and more difficult to catch than ever before.

Not surprisingly, the first species to be described scientifically were big and obvious. The earliest naturalists to visit Africa, for instance, could hardly fail to discover zebras, giraffes and elephants.

But recent discoveries are different. For instance, lizard species found today are generally smaller and more often nocturnal than other species of lizard. The tiniest of them, a thumbnail-sized chameleon from Madagascar, was discovered just a few years ago.

Three newly discovered species: (a) a snake-like amphibian from India; (b) the world’s tiniest lizard, and © the only lungless frog species.
B. Scheffers et al. (2014) Trends in Ecology & Evolution

Other unknown species are notoriously difficult to capture. For example, a biologist friend of mine was visiting his mother-in-law in north Queensland when her cat strolled in with an odd-looking animal in its mouth. He wrestled the cat’s dinner away and found that it was a mammal species never before seen in Australia called the prehensile-tailed rat.

Now known to be quite common in the Wet Tropics, this tree-dwelling rat almost never enters conventional wildlife traps. We can thank my mate’s mother-in-law’s cat for the discovery.

Other poorly explored places where new species wait to be discovered include the deep sea, soils and caves. After spending some 1,100 hours digging holes in the ground, biologists stumbled over the first species of Indian caecilian, a primitive, snake-like burrowing amphibian never before seen on the subcontinent.

On a far-flung beach in Alaska, a dead animal that washed ashore just last year turned out to be a completely new species of whale.

A frog species discovered in Borneo is the only frog in the world that completely lacks lungs. It lives in fast-flowing streams that are so oxygen-rich that it can breathe solely through its skin.

And a newly discovered spider in Morocco has evolved to move and escape predators by somersaulting over sand dunes.

The rainforest rooftop

High on the list of places to discover new species include rainforest canopies. In the early 1980s a Smithsonian Institution ecologist, Terry Erwin, used an insecticidal fog on several trees in the Panamanian rainforest and was stunned by his findings. Most of the insects that fell to the ground were entirely new species. Based on quick calculations he estimated that there could be 30 million species of insects residing in the canopies of the world’s rainforests.

Erwin’s conclusions, as it would be expressed today, went viral. In one fell swoop he had increased estimates of global biodiversity at least tenfold. Most biologists today consider his original estimate too high, however some believe he only overestimated a little.

Rainforest canopies are one of the world’s great biological frontiers.
William Laurance

Cryptic species

Beyond species that are difficult to find or catch, a lot of unknown biodiversity is staring us right in the face but we simply can’t see it. For these species, new discoveries are down to advances in molecular genetics. Around 60% of all new organisms described today are so-called “cryptic species” that are nearly indistinguishable from one another.

In recent years, for example, we’ve discovered that Africa has not just one species of elephant but two. Formerly considered different subspecies, genetic analyses reveal that they’re as dissimilar to one another as the Asian elephant is to the extinct woolly mammoth.

Genetic studies have also revealed hidden variation among Africa’s giraffes. Just last year, researchers revealed that what was once considered a single species of giraffe is actually four.

And in Costa Rica, one putative species of butterfly turned out to be at least ten.

Genetic studies have revealed that one apparent species of giraffe is actually four.
William Laurance

Molecular genetics is turning biology on its head in other ways. Organisms we used to think were only distantly related, such as antelopes, dolphins and whales, are practically cousins in evolutionary terms.

Epicentres of unknown species

One last reason why many species are yet to be discovered is that they only live in a small area of the world. Known as “restricted endemics”, these species are geographically concentrated in certain regions such as tropical mountains, islands, and climatically unusual environments.

Most of Earth’s restricted endemics reside in “biodiversity hotspots”, defined by having more than 1,500 locally endemic plant species and less than 30% of their original habitat remaining. Of 35 currently recognised hotspots, half are in the species-rich tropics with the remainder divided among Mediterranean, islands and other ecosystems.

The world’s 35 recognised biodiversity hotspots.
Conservation International

Today, the bulk of new species are being discovered in the biodiversity hotspots. The scary thing is that our recent analyses show that more than half of all hotspots have already lost over 90% of their intact habitat.

Further, most hotspots occur in poorer nations with rapidly-growing populations and escalating social and economic challenges, creating even greater pressures on their already beleaguered ecosystems and species.

Scary implications

Taken collectively, these studies suggest that there’s an enormous wealth of biodiversity on Earth left to discover and that much of it is in danger.

Further, our present knowledge is just scratching the surface. Evolution has had billions of years to create biologically active compounds that can combat human diseases, generate genetic diversity that could save our food crops from disastrous pathogens, and spawn ecological innovations that can inspire marvellous new inventions.

What a tragedy it would be to lose this biodiversity before we have ever had the chance to discover and learn from it.

A new species of Anglerfish discovered this year in the Gulf of Mexico. This bizarre fish has bioluminescent algae in the ‘fishing pole’ above its head to attract prey.
Theodore W. Pietsch, University of Washington

The Conversation

Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University

This article was originally published on The Conversation. Read the original article.

We discovered 20 new fish in northern Australia – now we need to protect them


Matthew Le Feuvre, University of Melbourne; James Shelley, University of Melbourne; Stephen Swearer, University of Melbourne, and Tim Dempster, University of Melbourne

We recently discovered 20 new species of fish in the Kimberley region of north-west Australia (one of them has been named after writer Tim Winton).

But that’s only the start of the story. At a time when the federal government is redoubling efforts to develop northern Australia, our discovery is a timely reminder of how little we know about our country.

A 2014 CSIRO report found 1.4 million hectares of land in northern Australia could be irrigated. Underlying this expansion would be approximately 90 large dams and numerous smaller water-regulating structures such as weirs.

While this could boost the northern Australian economy, impacts on aquatic ecosystems from altered flow regimes, habitat modification and reduced water quality are likely to be significant.

The long-nosed sooty grunter is found in a single river in the Kimberley.
Matthew Le Feuvre & James Shelley, Author provided

Threatened waterways

Fish are the most researched group of species living in Australia’s freshwater ecosystems. As such, we can use them as indicators of how much we know about these environments.

To date, research effort has been focused on south-east Australia. What stands out is a lack of research across much of the country, particularly in the north.

Despite this, northern Australia’s freshwater fish fauna is very diverse and includes many fish found across tiny areas. Unfortunately the lack of research means that for many of northern Australia’s fishes, all we know is that they exist.

Under the federal Environment Protection and Biodiversity Conservation (EPBC) Act, 16% of Australia’s freshwater fish are listed as threatened. But most of the species analysed are from the rivers of south-east Australia, which are most affected by people.

In a recent study we identified another 55 potentially vulnerable species that meet the criteria for conservation listing.

When we mapped the already listed and potentially vulnerable fish species, we found hotspots for fish conservation in the Kimberley, the Wet Tropics and Arnhem Land.

Map a) shows the number of currently listed threatened fish. Map b) shows the number of species that we identified as potentially vulnerable. Map c) shows river condition (1=best quality; 8=worst). Map shows d) freshwater fish research effort across Australia (red=most effort).
Matthew Le Feuvre, Tim Dempster, James Shelley and Steve Swearer, Author provided

While often overlooked, Australia’s freshwater fish are almost as unique as our kangaroos and koalas: 74% of these fish are found nowhere else in the world.

If enigmatic northern Australian species, such as the saratoga (Scleropages leichardti), the long-nosed sooty grunter (Hephaestus epirrhinos) or the Prince Regent gudgeon (Hypseleotris regalis) are lost, we contribute to an ongoing global freshwater fish extinction crisis. Australia’s freshwater fish deserve adequate protection.

Exploring the north

The Kimberley in northern Western Australia is rugged, remote, pristine and holds a number of species found nowhere else. We decided to investigate the region’s freshwater fishes.

Before our project began, we knew that the region was home to 50 species of freshwater fish, or almost a quarter of Australia’s freshwater fish species. Eighteen of these are found only in the Kimberley region.

Over the past three years, we spent nine months surveying over 70 sites on 17 of the Kimberley’s rivers. We found that many of the endemic species are potentially particularly vulnerable if their environment were to change. For example, the long-nosed sooty grunter is large, found in a single river, rare and exclusively carnivorous, making it vulnerable to extinction.

Excitingly, we also uncovered 20 new species of freshwater fish. This increases the known freshwater fish species in Australia by roughly 10% and, with 70 species in total, it makes the Kimberley the most diverse region for freshwater fish.

Many of the new species are large, clearly distinct fish, which could be identified as new species when we observed them from the riverbank. We found most of these new species in rivers we could only access by helicopter.

Put simply, due to the difficultly and expense of sampling the remote Kimberley wilderness, we just haven’t looked hard enough in the region’s rivers. Entire river systems in the Kimberley remain unsampled and we should not be surprised to uncover more species unknown to science.

What else is out there?

Our findings raise questions about the environmental sustainability of developing northern Australia. If we can find 20 new species of freshwater fish in nine months of fieldwork in the Kimberley, how many more species are present across the rest of northern Australia?

Fish are big and easy to find compared to most of the smaller aquatic life. They represent the conspicuous tip of the iceberg of what lives in our rivers. What happens if we investigate more cryptic or poorly known taxa such as amphibians or invertebrates?

The Prince Regent gudgeon.
Matthew Le Feuvre & James Shelley, Author provided

How can we manage and protect species we don’t know exist? Before we develop the north, we need to know what’s out there.

The majority of northern rivers remain in relatively good condition, so there is ample opportunity to ensure that species are not lost as a result of development. Fortunately, most major developments are a decade or more away, so there is time to gather this information.

Learning from the south

Many rivers in southern Australia have been degraded by habitat modification, altered flow patterns, invasive species, barriers to fish movement, reduced water quality and overexploitation.

Many fish species are threatened. Of 46 species found in the Murray-Darling Basin, 19 are listed as threatened at the state or national level.

What have we learned?

River flow, infrastructure and land use all need to be actively managed to maintain healthy rivers and allow key ecological processes, such as migrations and the inundation of floodplains, to continue. We need to be vigilant to prevent alien species invading.

A major source of conflict in the Murray-Darling Basin Plan was the allocation of water to the environment. Considering the environment as a stakeholder at the beginning of this process could have avoided future conflicts.

These practices will need to be adapted to the highly seasonal rainfall of northern Australia, which will be challenging. Intact rivers with particularly high numbers of species found nowhere else may be good candidates for freshwater protected areas, which are rare in Australia.

We need to ensure that our unique freshwater fishes are properly conserved. With research and good planning, we can ensure we do not repeat the sins of the past in northern Australia.

The Conversation

Matthew Le Feuvre, PhD candidate, School of BioSciences, University of Melbourne; James Shelley, PhD candidate, School of Biosciences, University of Melbourne; Stephen Swearer, Professor of Marine biology, University of Melbourne, and Tim Dempster, Associate professor in Marine Biology, University of Melbourne

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