Oct 062014
 

Original story at PSNews online

A 2,000 kilometre project to help native fish species travel up the River Murray is to take out man-made obstacles along the river system.
Macquaria ambigua: Golden Perch or Yellowbelly.

Macquaria ambigua: Golden Perch or Yellowbelly.

The $70 million Sea to Hume fishway program near Waikerie in South Australia's Riverland includes 17 fishways designed to help native fish species navigate major weirs and barrages.

The Minister for Water and the River Murray, Ian Hunter said the new fishways would help to increase the population and distribution of more than 25 species of native fish such as Murray cod and golden perch.

"While locks, weirs and barrages play an important role, mainly in the navigation of boats through different sections of the river, they restrict the natural movement of some native fish," Mr Hunter said. Continue reading »

Sep 162014
 

Original story at ABC News

Three-quarters of the trash found off Australian beaches is plastic, a new study says, warning that the rubbish is entangling and being swallowed by wildlife.
Litter impacts wildlife through entanglement and ingestion, with 43 per cent of seabirds from study discovered with plastic in their gut.

Litter impacts wildlife through entanglement and ingestion, with 43 per cent of seabirds from study discovered with plastic in their gut.

Researchers surveyed the vast Australian coastline at intervals of about 100 kilometres, compiling the world's largest collection of marine debris data, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) said.

"We found about three-quarters of the rubbish along the coast is plastic," CSIRO scientist Denise Hardesty said.

"Most is from Australian sources, not the high seas, with debris concentrated near cities."

The report, part of a three-year marine debris research and education program developed by Earthwatch Australia with CSIRO and energy group Shell, found there were two main drivers of the pollution - littering and illegal dumping.

Rubbish found included glass and plastic bottles, cans, bags, balloons, pieces of rubber, metal and fibreglass, as well as fishing gear and other items lost or discarded in or near the sea.

The report said this marine debris not only posed a navigation hazard but could smother coral reefs, transport invasive species, harm tourism and kill and injure wildlife.

It warned that litter impacted wildlife through entanglement and ingestion, but also indirectly via the chemicals it introduced into marine ecosystems.

Smaller turtle species in particular ingested the debris, possibly because soft, clear plastic resembled its natural prey jellyfish. Continue reading »

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 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 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 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 »

Jun 252014
 

Original story by Bianca Nogrady, ABC Science

The unique damselfish practice of cultivating their favourite type of algae on coral reefs contributes to an increase in coral disease, Australian researchers have found.
Damselfish are known for their habit of 'farming' a particular species of algae found on coral reefs Photo: Jordan M Casey

Damselfish are known for their habit of 'farming' a particular species of algae found on coral reefs Photo: Jordan M Casey

The study, published in the Proceedings of the Royal Society B, also suggests that overfishing of other fish species may contribute to an increase in the numbers of damselfish, which in turn may boost coral disease.

Damselfish are known for their habit of 'farming' a particular species of algae found on coral reefs -- often to the detriment of the coral itself, says lead author and PhD candidate Ms Jordan Casey from the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University.

"They weed out the stuff they don't like, they farm the good stuff, they keep it at a certain level where it continues to grow, and they're constantly engaging in very aggressive behaviour that keeps other fish outside of their territories so they can't feed on this very good palatable feeding algae," says Casey.

Previous research has suggested that this farming behaviour, which leads to algal dominance over coral, has implications for the health of the coral but no one had explored what was going on at the microbial level.

To explore how the practice affects coral, the team looked at the DNA of microbial populations present in areas of the Great Barrier Reef populated by two different species of damselfish. They found a much greater abundance of bacteria linked with coral black band disease inside the damselfish territories than outside their range. Continue reading »

Jun 152014
 

Original story by Kerry Staight at ABC News

The lure of a lucrative European market is prompting a growing number of Australian shellfish producers to invest in native angasi oysters.
Angasi oysters being farmed at Coffin Bay. Photo: ABC/Kerry Staight

Angasi oysters being farmed at Coffin Bay. Photo: ABC/Kerry Staight

The flat oyster already fetches around double the price of the better known Pacific oyster domestically, and the industry says it could potentially fetch up to five times the price in countries like France. Continue reading »