Aug 192014
 

Original story at ABC News

The critically endangered western trout minnow has been bred in captivity for the first time, in a program that is hoped will help shore up the population.

The western trout minnow was the first freshwater fish species in Australia to be listed as critically endangered. Photo: Department of Fisheries WA

The western trout minnow was the first freshwater fish species in Australia to be listed as critically endangered. Photo: Department of Fisheries WA

The western trout minnow is so rare it is only found in three small rivers in WA’s Great Southern region.

It was the first freshwater fish species in Australia to be listed as critically endangered.

Researchers from the University of Western Australia and the Department of Fisheries have managed to breed the fish in a laboratory, and hope to restock the rivers in a couple of years.

Principal research scientist Dr Craig Lawrence said there is also a team examining the reasons why the fish are becoming extinct.

“They are specifically looking at the reasons why several rare species in WA have got very low numbers in the wild,” he said.

“Once those factors are identified, we will put together a strategy to address them and it’s only then that we would look at restocking.”

Dr Craig Lawrence has bred the rare minnow in captivity for the first time. Photo: ABC News/Anna Vidot

Dr Craig Lawrence has bred the rare minnow in captivity for the first time. Photo: ABC News/Anna Vidot

In 2006 it was estimated that between 2,000 and 5,000 minnows remained in the wild.

Dr Lawrence said researchers had to break new ground in figuring out how to breed the fish.

“We had to work out how to keep them, feed them, breed them, incubate the eggs, raise the embryos, hatch the larva out, and rear them up to fry,” he said.

“They need specific cues to breed. They need the right flow rate, the right temperature, the right barometric pressure.”

He said weirs and dams on water bodies changed the way the rivers flow, which affected the fish’s breeding in the wild.

In one case, researchers built a “fish ladder” to help the animals get around the barriers, and this may need to be installed in other areas too, Dr Lawrence said.

Western trout minnow embryos. Photo: Department of Fisheries WA

Western trout minnow embryos. Photo: Department of Fisheries WA

The fish’s size was also a factor in breeding it in captivity, he said.

“When we’re talking about these fish, we’re scaling everything down to 1:1000 of what we would usually use,” he said.

“The accuracy of the injections and anaesthesia we use have to be very rigorous and there’s very little room for error.

“No-one else has used these techniques before for a fish of this size.”

The research has been carried out over five years, but the fish only breed four weeks out of the year, Dr Lawrence said.

Aug 042014
 

By Christopher Brown at The Conversation

Tighter bag limits for fishing could be the key to ocean conservation, according to new research showing that limiting fishing across entire regions can offer better protection than using marine reserves.
Fishing of potato rock cod is totally banned in Queensland waters. Better regulation might avoid similar bans for other species. Photo: Mark Priest

Fishing of potato rock cod is totally banned in Queensland waters. Better regulation might avoid similar bans for other species. Photo: Mark Priest

Continue reading »

Jul 192014
 

News release from The University of Exeter

The tiny plastic particles polluting our seas are not only orally ingested by marine creatures, but also enter their systems through their gills, according to a new study led by the University of Exeter.
Photo: Shutterstock

Photo: Shutterstock

Scientists also discovered that when microplastics are drawn in through this method they take over six times longer to leave the body compared with standard digestion.

Lead author Dr Andrew Watts of Biosciences at the University of Exeter said: “Many studies on microplastics only consider ingestion as a route of uptake into animals. The results we have just published stress other routes such as ventilation. We have shown this for crabs, but the same could apply for other crustaceans, molluscs and fish – simply any animal which draws water into a gill-like structure to carry out gas exchange.

“This is highly important from an ecological point of view, as if these plastics are retained longer within the animal there is more chance of them being passed up the food chain.”

The researchers used fluorescently labelled polystyrene microspheres to show how ingested microplastics were retained within the body tissues of the common shore crab, Carcinus maenas. Multiphoton imaging suggested that most microspheres were retained in the foregut after sticking to hair-like ‘setae’ structures within the crabs. Continue reading »

Jul 172014
 

Original story by Jake Sturmer, ABC News

A world-first study has found that dredging can more than double the level of coral disease in reefs.
Joe Pollock researches the impact of dredging on coral. He says his study on the impacts of dredging highlights the pressure reefs face. Photo: Ed Roberts

Joe Pollock researches the impact of dredging on coral. He says his study on the impacts of dredging highlights the pressure reefs face. Photo: Ed Roberts

Scientists have known for decades that dredging can smother corals, but researchers say this is the first time it has been linked to diseases.

With dredging approved in the world heritage listed Great Barrier Reef Marine Park, the scientists hope their work draws attention to the pressing issues facing the region.

The study by the Australian Research Council’s Coral Reef Studies Centre of Excellence looked at the 7 million cubic metres of dredging done for Chevron’s Gorgon Gas Project off Western Australia’s coast.

“There was a fair bit of dredging going there and this was an ideal opportunity to use this natural experiment to look at the impacts of dredging, sediment and turbidity on coral health,” lead author Joe Pollock said.

“What we’ve found is that you get two times as much coral disease near the dredge sites as you do at nearby control sites.”

Not all diseases are fatal but Mr Pollock said they can have a significant impact on reef health. Continue reading »

Jul 092014
 

Original story by Bianca Nogrady, ABC Science

Plant-eating tropical fish species are causing serious damage to algae and kelp forests in sub-tropical and temperate regions around the world, an international team of experts warn.
Pretty tropical fish are devastating kelp forests. Photo: Adriana Verges

Pretty tropical fish are devastating kelp forests. Photo: Adriana Verges

The findings come from a review published today in the Proceedings of the Royal Society B, which suggests that climate change is leading to ‘tropicalisation’ – the movement of tropical species towards the poles – as waters get warmer and ocean currents strengthen.

It reveals how algae and kelp-eating tropical fish such as rabbitfish have already led to the collapse of kelp forests – and their associated abalone fisheries – in Japan, and decimated the canopy-forming algae forests in the Mediterranean.

Two herbivorous tropical species – rabbitfish and drummer fish – have also been implicated in the loss of kelp forests on both the east and west coasts of Australia, says lead author of the study Dr Adriana Verges, marine ecologist at the University of New South Wales.

Overgrazing of algae and kelp by fish hampers recovery of the ecosystem from events such as heatwaves. Continue reading »

Jul 092014
 

Original story by Peter Kyne, Charles Darwin University at The Conversation

Sawfish are the most endangered group of marine fish in the world, largely thanks to overfishing and habitat loss. Formerly abundant, they have disappeared from many countries’ waters, and in many others they are scarcely holding on.
The world’s five species of sawfish are the most threatened fishes in the world. Photo: David Wackenfelt

The world’s five species of sawfish are the most threatened fishes in the world. Photo: David Wackenfelt

To put it bluntly, sawfish have been devastated. But we could reverse the trend. Recently the International Union for Conservation of Nature’s Shark Specialist Group released the first Global Sawfish Conservation Strategy. It won’t be easy, but they are steps we need to take if we are to save the world’s threatened sawfish. Continue reading »

Jul 082014
 

Original story by Selina Bryan, ABC News

Scientists at the Tamar Island Wetlands near Launceston are about to wage genetic warfare on a small pest that is causing a lot of trouble.

The mosquito fish, or gambusia, was introduced to Australia more than 100 years ago to fight malaria and was released in the Tamar in the 1990s.

Because the gambusia thrive in calm shallow water and feed off insect larvae, they seemed to be the ideal mosquito control agent.

But being fast breeders and voracious eaters, the mosquito fish, like the cane toads of the mainland, have become the problem.

Now the University of Tasmania is leading a national campaign to eradicate the fish with the support of a $476,000 grant. Continue reading »

Jul 062014
 

Original story at Australia Network News, ABC

Scientists are concerned that hundreds of thousands of tons of plastic waste floating in the ocean is being eaten by fish.

Scientists believe fish may be eating tons of plastic waste. Photo: Great Barrier Reef Marine Park Authority

Scientists believe fish may be eating tons of plastic waste. Photo: Great Barrier Reef Marine Park Authority

An international team of experts has found evidence there is 100 times less plastic on ocean surfaces than expected.

Professor Carlos Duarte, an oceanographer from the University of Western Australia, was part of the study that towed a mesh net through the world’s oceans.

He told Pacific Beat there are a number of possibilities for where the missing plastic has gone but one stands out.

“The disturbing reality is that we cannot account for where the 99 per cent that is missing may be,” he said.

“The plastic particles that are missing might be ingested by fish. That one possibility is… the most likely one.” Continue reading »

Jul 052014
 

Original story at Bush Telegraph

One of the oldest fish species in Australia that predates the breaking up of Gondwanaland, is under threat.
The ancient Salamander Fish, the Lepidogalaxias salamandroides, is facing threat from a lack of rainfall and a predator. Photo: Brad Pusey

The ancient Salamander Fish, the Lepidogalaxias salamandroides, is facing threat from a lack of rainfall and a predator. Photo: Brad Pusey

The salamander type fish is found in an isolated pocket of Western Australia in an area known as the Southern Acid Peat Flats, west of Albany. Continue reading »

Jul 032014
 

Original story from the Society for Experimental Biology via EurekAlert!

This image shows tropical damselfish (Chromis viridis) schooling in a coral reef. Photo: Lauren Nadler

This image shows tropical damselfish (Chromis viridis) schooling in a coral reef. Photo: Lauren Nadler

Like humans, fish prefer to group with individuals with whom they are familiar, rather than strangers. This gives numerous benefits including higher growth and survival rates, greater defence against predators and faster social learning. However, high carbon dioxide levels, such as those anticipated by climate change models, may hinder the ability of fish to recognise one another and form groups with familiar individuals.

Scientists at the ARC Centre of Excellence for Coral Reef Studies at James Cook University, Australia, have been studying the effect of carbon dioxide on the schooling behaviour of the tropical damselfish Chromis viridis. Lead investigator Miss Lauren Nadler found that juvenile fish normally require three weeks to recognise their school-mates, however elevated carbon dioxide levels significantly impaired this ability. Continue reading »