Friday Fishy News - July 20

[Flattieman]

Hey, Raiders!

Long time, no chat! Well... I attended the ISS as described in the last edition of Friday Fishy News - they were two of the best weeks of my life! Made heaps of awesome friends and learned a lot in the process - the social life really made it awesome, though! So much so that I've been to distracted by chatting on MSN to get back into the swing of things on FR! Anyway, I'll try to catch up on some of the posts I've missed (there's HEAPS) in time... In the meantime, here's the news!:

Considering that I learned about climate change for two weeks, I think the next story is an apt choice to kick this edition off...

Climate to put heat on fish stocks

By Ewin Hannan

The Australian

July 9

CLIMATE change is likely to put significant pressure on the nation's fish stocks, with new CSIRO research identifying the eastern and southeast coastlines as the most vulnerable to warming temperatures.

A new CSIRO climate change vulnerability index, to be launched today, finds coastal waters will warm by up to two degrees by 2030, encouraging fish to move south, threatening marine turtles, and potentially pushing box jellyfish down the east coast.

Scientists said yesterday fishing stocks potentially faced a "double whammy" from the consequences of fishing and climate change.

The climate change index, developed by CSIRO's Marine and Atmospheric Research Unit, considered seven large marine domains around Australia and determined their vulnerability to climate change based on five dimensions.

These were biological, regional characteristics, climate change, fishing, and other stress factors caused by human activity.

The index revealed that the eastern-central and southeast domains were the most vulnerable to the impact of climate change.

The index predicts that sea surface temperatures around Australia will warm by 1-2C by 2030, and by up to 3C by 2070, with the greatest warming off southeastern Australia and the Tasman Sea.

Anthony Richardson, a member of the CSIRO's Wealth from Oceans Flagship, said the advantage of the index was that it identified principal stress factors for each domain, and allowed the development of regional policies to tackle climate change.

Dr Richardson said that as waters warmed along the east coast, fish and marine life would be encouraged to move south.

He said scientists believed potentially fatal box jellyfish could move south from Queensland.

"The east Australian current which flows south along the east coast will strengthen and take jellyfish further south," he said. "The conditions there will be warmer so they may do OK further south so that has implications for bathing."

Dr Richardson said the impact of climate change would have potential significant consequences for the nation's fishing industry, with warm-water fish likely to move south, and cold-water fish also expected to retreat down the coast.

"I think the fishing industry is starting to be concerned about the impact of climate change," he said. "They are fishing heavily, and the changing environmental considerations are all stresses in the future. Pressure from fishing and climate change represent a double whammy for the industry."

Professional fisherman Rolf Norington has already seen a change in the species he catches over his 25 years in the industry.

Now licensed to catch only prawns and squid, Mr Norington, from Brooklyn, north of Sydney, said that warmer currents sweeping down the coast from Queensland had brought the spawn of new species into Broken Bay.

"With the 13 years of drought we have just faced, the Hawkesbury River system has had little flow and the saltiness of the water has allowed new species to grow and breed," he said as he prepared his boat, Australia Star, for this week's work.

"If we are allowed to address the problems caused by drought and climate change, it will be nice, but we are being regulated out of existence and our markets are being taken by imported prawns and other seafood."

Mr Norington said the existing conditions placed on prawntrawlers prevented them from taking any fish species with amateur fishing bag limits and also prevented them from working on weekends and public holidays.

"We are always painted as the bad guys ... raping the fishing resource, but nothing could be further from the truth," he said.

"It is our livelihood. Why would we destroy it?"

Mr Norington, 41, said he and other professional fishermen were keen to work with government bodies and environmentalists to ensue that Australians could continue to enjoy fresh local seafood and not rely on frozen produce brought in from Asia.

According to the CSIRO, the warming waters will also result in an increased number of female marine turtles being born, making it more difficult for the turtles to mate in the future.

The index will be presented to the Australian Marine Science Association conference starting in Melbourne today. The conference will also consider research examining the impact of warming waters on climate change.

The CSIRO's Elvira Poloczanska said fish on the east coast that were living on or near the sea bed had shifted southwards as coastal waters warmed.

"The large giant kelp forests that are found fringing the coasts at spots in southern Australia support a myriad of fish and other animals," she said. "These cold-water seaweeds are at high risk in Australia from warming waters. Kelp forests on the east Tasmanian coast are already in decline as sea temperatures increase."

and a similar story...

Warming waters to drive fish south: CSIRO

ABC News Online

By Timothy McDonald

July 9

A CSIRO study of the waters off the south-east coast of Australia reveals that they are warming up faster than anywhere else in the southern hemisphere.

The scientists warn that these warmer waters will not only dramatically change the marine environment, but could devastate local fisheries.

However fisherman from the area say they are not worried yet because they have just had their best catch in years.

Steve Buckless, a fisherman from the NSW south coast, says this year's catch has been outstanding.

"Just general trawl fish - which is flathead, ling, blue grenadine - most of those species are more abundant this year than they have been for the last seven or eight years," he said.

"We're finding the catchability (sic) has increased incredibly this year."

But the CSIRO study suggests that the good times will not last for ever, because the normally cool waters off the south-east of Australia are warming up.

CSIRO marine biologist Dr Anthony Richardson says that could have a huge impact on marine life that thrives in cooler climates.

"In the next century the greatest warming in the Southern Hemisphere will be off south-east Australia and in the Tasman Sea," he said.

"That's likely to be about two to three degrees in the next 50 years and that's likely to have major impacts on fisheries and other forms of marine life.

'Vulnerable'

The cooler waters off south-eastern Australia are rich in nutrients and support a diverse range of sea life.

But Dr Richardson says the fish that live there could be vulnerable, because they need to stay within a relatively narrow band of temperatures in order to survive.

He says if the waters warm up, subtropical fish will move in from the north and local species will retreat further south in search of a more comfortable climate.

That is a problem because fish feed on nutrients that wash into the sea from a nearby landmass, and if they are pushed too far south they will run out of land.

"One of the problems in Australia is that there is, if you like, a costal habitat," he said.

"If you're a fish there's so only so far you can move south before you run out of landmass.

"So that's of concern.

"But there's also groups of species, like kelps for instance, that prefer cold, nutrient rich water and as that becomes less and less common in the future those sort of species, like kelp, are likely to do poorly.

"There's a whole community that are found around kelp forests and the kelps in Tasmania, for instance, are already showing a decline.

Commercial fishing

Dr Richardson the warmer waters could also have a negative effect on commercial fishing, because they are not as productive.

"It will also affect the productivity because the warm water and the east Australian current that runs south is likely to penetrate further south and that is low nutrient water," he said.

Mr Buckless says global warming may have some long-term consequences for his business, but the drought has had a much larger impact over recent years.

"I wouldn't argue with the theory that fish could move south, but it's also got a lot to do with the drought effects we've been seeing currently," he said.

"I wouldn't argue that over a long period of time computer models are going to show the warm waters are pushing further south, but ... we're certainly not seeing that this year."

Excavation begins on Darling River to give fish new homes

ABC Rural

July 19

Work has started in the lower Darling River to provide new homes for native fish.

While for years fallen trees were removed from the river bed to make room for boats, they are now being replaced by authorities.

Excavators have been called in to help winch the logs into selected parts of the river.

The New South Wales Department of Primary Industries' Mark Neeson says a wide range of fish will benefit.

"Murray Cod tend to like snags to use as a home site and also as a breeding site and the Golden Perch are often found around the snags because they not only shelter from them, but they also are able to feed on shrimp that graze on the algal films that grow on the timber," he said.

Call for greater fish stocks protection

ABC News Online

July 19

The Western Australian fishing industry says urgent action is needed to stem the decline of scalefish stock.

The WA Fishing Industry Council says dhufish and snapper stocks are particularly vulnerable.

Council chief executive officer Graeme Stewart says the stocks need greater protection to ensure they do not become extinct.

He says bag limits need to be tightened.

"The precaution ... will prevail, that is to say we operate ... with a great deal of caution, it's very susceptible to, if not extinction, to certainly being fished to extremely low levels, to dangerously low levels," he said.

Fish stocks surge not only indicator of estuary health

ABC News Online

July 9

Researchers are warning against using a surge in fish stocks in the Wilson Inlet, in southern Western Australia, to measure the estuary's health.

A group of researchers from Murdoch University is conducting a two-year study looking at fish numbers and species in six south coast estuaries.

The program includes tagging and releasing fish species, including black bream, king george whiting, herring, cobbler and mullet.

Researcher Ben Chuwen says while the Wilson Inlet is in good health now, it could be facing a collapse in fish stocks, like the Peel Harvey Inlet did 20 years ago.

"Looking at the data that we have so far, it certainly is looking very similar to what happened to the Peel Harvey [inlet] 20 or 25 odd years ago, so there's a lot of growth of algae and a lot of food and a lot of shelter for these species at the moment, but if we look to the future and perhaps something starts changing, we might indeed see a collapse," he said.

Govt 'not testing' Chinese fish imports

The Age

July 13

The federal government does not test for contamination in imported Chinese fish despite US officials banning imports because of worries antibiotics are infiltrating the food chain.

The US Food and Drug Administration (FDA) issued an alert on June 28 saying it would stop all Chinese farm-raised eel, catfish, basa, shrimp and dace at its border.

FDA assistant commissioner David Acheson cited concerns over high levels of antibiotics in the seafood.

Agriculture Minister Peter McGauran's office has not yet responded to questions on whether the Australian government is testing for the antibiotics, known as fluoroquinolones.

But the Australian Quarantine and Inspection Service confirmed no testing for fluoroquinolones is done without a specific request from Food Standards Australia and New Zealand.

"No, we don't do that test," a quarantine spokesman said.

Labor has attacked Mr McGauran for failing to act on the US warning.

"Australia does not screen for fluoroquinolones," Labor's agriculture spokesman Kerry O'Brien said in a statement.

Senator O'Brien said the issue needed urgent attention.

"This means urgently increasing testing frequency for the full range of potentially harmful contaminants including nitrofurans and fluoroquinolones."

Microbiologist John Turnidge of Adelaide's Women's and Children's Hospital says the risks created by fluoroquinolones entering the food chain are great.

The major concern, he said, was that if the antibiotics enter the food chain people will begin building up an immunity to fluoroquinolones, as has happened with other antibiotics.

"The small amounts that might be in food could theoretically select for resistance in the bacteria that you and I carry in our guts," Professor Turnidge said.

"For all of those reasons we would be very unhappy to see fluoroquinolones in the flesh of imported fish."

Prof Turnidge said he was not aware of what, if any, monitoring for fluoroquinolones was done by the government.

NT barramundi farm investigates fish feeding habits

ABS Rural

July 2

A barramundi farm in the Top End is investigating the sounds fish make when they are eating.

Humpty Doo Barramundi's Bob Richardson says fish feeding is the most expensive part of the operation and is often dominated by more aggressive fish.

Feed is also wasted because it is not distributed evenly.

He says they are now piloting new technology which could improve feeding efficiency by more than 10 per cent.

Maine studies effect of plastic, rubber lures on fish

Boston Morning Sentinel

July 4

UNITY, Maine --A marine biologist with the Maine Department of Inland Fisheries and Wildlife hopes that his study will help to determine the effects of plastic and rubber lures on fish that swallow them.

Scuba divers and fisheries biologists have found these lures, made in a variety of shapes, sizes and colors, littering the bottoms of Maine's lakes and ponds following the growing popularity of bass fishing.

But Russell Danner is more interested in what happens to them when they're ingested by fish.

"We're just looking to see if it causes any health problems," Danner said.

Danner's study could lead to legislation that would curtail the use of traditional, indigestible plastic lures. Since biodegradable artificial lures are already on the market, "they would be a good choice even now," he said.

To study the lures' effects, Danner split 70 hatchery-raised brook trout into two groups, placed them in tanks at Unity College. Over 90 days, one group of fish was fed food, while the second group ate food spiked with soft plastic lures.

The feeding portion of the study ended last week, when the fish were euthanized and Danner began a battery of tests.

He was startled to find that fish were eating large pieces of lures that were remaining undigested in their stomachs.

Slicing open a 9-inch trout in the laboratory, Danner discovered a 1-inch long piece of rubber worm in its belly. Later, a 9-inch plastic salamander popped out when Danner cut into a similar-sized fish.

Because the fish were fed different colored lures each week, Danner will be able to learn how long the lures stay with the fish.

Jim Chacko, the college's professor of aquaculture, discovered a difference even before the fish were euthanized. Holding a small can of food, he tossed a small handful into the tank with the healthy fish, which swarmed to the top to grab a piece.

When food was tossed into the tank of fish that had consumed the lures, however, the fish slowly made their way to the top to nibble.

"I think it's because their stomach is full so their reaction is very slow," Chacko said.

Danner found an excess amount of green bile inside a number of fish, which is an indication the fish are not eating properly, he said.

The fish were measured and weighed and a blood sample was taken to measure glucose levels, the ratio of red blood cells and blood protein.

The readings, measurements, stomach and liver contents, and the fish themselves, will be compared to those provided by the pure food group to learn how the plastic lures effect the fish overall health.

Coral Reef Fish Need Decades Or Longer To Recover

Science Daily

July 13

In the longest running study on how fish populations in coral reef systems recover from heavy exploitation, researchers from the Wildlife Conservation Society (WCS) and others have found that the fish can recover, but they need lots of time -- decades in some cases.

With nearly continuous data spanning some 37 years from four national marine parks off the coast of Kenya which were closed to fishing at different times, the study found that commercially important species such as parrotfish, wrasses, and surgeonfish can take a quarter of a century to recover fully. More importantly, the ecological equilibrium needed for a healthy reef system, which relies on the interplay of many fish, invertebrate, and plant species, take even longer to achieve, and certainly longer than the length of the study. Most fish recovery studies are conducted with small data sets in short durations of time.

"There's a pressing need for long-term studies on how fish communities in reef ecosystems rebuild when fishing is banned," said WCS researcher Dr. Tim McClanahan, the lead author of the study. "This study gives us some important insights in how the different fish species recover and how these communities affect the health of the reef as a whole."

Specifically, the study examined the recovery rates of eight dominant fish families in Kenya's marine national parks between 1987 and 2005 using counts that measured fish diversity, size, and density. What the researchers found is that species diversity peaked and stabilized 10 years after a marine park was closed to fishing. The recovery rates of different families and species, however, occurred at different rates, partly as a result of competition for resources among different species. For instance, most parrotfish took some 10-20 years to recover, but then declined, perhaps as a result of competition from a variety of surgeonfish.

A group of fish known as wrasses increased and then peaked in diversity and numbers after 10 years and then their abundance declined, perhaps as a result of competition with triggerfish for the same invertebrate prey. One species of triggerfish--the orange-lined triggerfish--became dominant in the parks with the longest fishing bans, actively excluding other competitors from territories.

Triggerfish are important in another respect; they feed on sea urchins, which in turn feed on the reef-building algae on which the entire reef system depends. When fishing eliminates species that prey on sea urchins, the invertebrates can severely impact the entire system, so keeping sea urchins in check is vital to coral reefs.

Overall, the time frame needed by surgeonfish and tangs, triggerfish, rabbitfish, and the coral-building algae to completely rebuild their populations to pre-fishing levels may exceed the length of the study."Decisions made by managers to close areas to fishing in an effort to save fish populations can be unpopular but necessary," added McClanahan. "What this study has shown us is that many fish populations take long periods of time to recover fully, and that permanent bans on fishing in some parks are necessary if we're to conserve healthy coral reef systems."

The study appears in a recent edition of the journal Ecological Applications.

East African Fishermen Catch Rare Ancient Fish

FOX News

July 16

ZANZIBAR, Tanzania — Fishermen have caught a rare and endangered fish, the coelacanth, off the coast of the Indian Ocean archipelago of Zanzibar, a researcher said on Monday.

The find makes Zanzibar the third place in Tanzania where fishermen have caught the coelacanth, a heavy-bodied, many-finned fish with a three-lobed tail that was thought extinct until it was caught in 1938 off the coast of South Africa.

Since then two types of coelacanth have been caught in five other countries: the Comoros, Indonesia, Kenya, Madagascar and Mozambique, according to the African Coelacanth Ecosystem Program.

"Fishermen informed us that they caught a strange fish in their nets. We rushed to Nungwi (the northern reaches of Zanzibar) to find it's a coelacanth, a rare fish thought to have become extinct when it disappeared from fossil records 80 million years ago," said Nariman Jiddawi of the Institute of Marine Sciences, which is part of the University of Dar es Salaam in Tanzania's commercial capital.

Trade in the coelacanth is banned under the Convention on International Trade in Endangered Species of Wild Fauna and Flora.

"Zanzibar will join a list of sites of having the rare fish caught in its own waters," said Jiddawi, adding the catch weighed 59.5 pounds and measured 4.4 feet.

Four fishermen caught the fish on Saturday, Jiddawi said.

Mussa Aboud Jume, director of fisheries in Zanzibar, said that the coelacanth will be preserved and put on display at the Zanzibar Museum.

A statement of the Institute of Marine Sciences said that 35 coelacanths have been caught since September 2003 in Mtwara, a southern region of Tanzania, and mostly along the coast of Tanga in Tanzania's north.

Coelacanths are the only living animals to have a fully functional intercranial joint, a division separating the ear and brain from the nasal organs and eye, according to an Institute of Marine Sciences statement.

When fish get emotional

New Scientist

July 9

Who ever heard of a fish being in two minds about something? Yet it seems that like humans, fish process information - and perhaps emotions - on different sides of the brain.

Fish growing up in the wild among predators use their left eye to look at novel objects, while their offspring raised in captivity use the right eye. This suggests that life experiences can affect which side of the brain fish use, and even, says Victoria Braithwaite of the University of Edinburgh, UK, that they have emotional mindsets, since different sides of the brain may correspond to a curious or suspicious attitude.

"The lab-reared fish could process information about novel objects in the left brain [which means they are looking at things with their right eye] because they feel more comfortable, whereas their parents are more cautious."

Humans use their left and right brain lobes differently, the most well-known consequence being handedness. Brain lateralisation has been found in an increasing number of other species in recent years.

"Especially for animals that have to cope with many predators, it is an advantage if they can use one hemisphere to keep an eye on predators while they use the other hemisphere to do other things," says Culum Brown, now at Macquarie University in Sydney, Australia.

Brown and his team caught bishop fish (Brachyraphis episcopi), which are similar to guppies (see Photo), from areas with high and low predation rates in Panama. The team bred the fish in the lab and then tested the behaviour of both the wild parents and their offspring. Fish swam towards a slatted barrier through which they could see either a novel object (a yellow cross), nothing, or another bishop fish. They could then swim past the barrier either to the left or to the right. Exiting to the left meant the fish had kept its right eye on the barrier, and vice versa.

Neither fish from areas of low predation nor their young showed much of a preference for a left or right exit, suggesting their brains were not very lateralised. However, fish that had to deal with a lot of predators in the wild favoured one eye, as did their lab-born offspring, especially when viewing the novel object (Animal Behaviour, DOI: 10.1016/j.anbehav.2006.08.014).

"This shows that a tendency for brain splitting can be inherited," says Braithwaite. "But amazingly, the captive-born offspring preferred the right eye when their parents preferred the left. So the way the fish then use this brain division is a learned thing."

Giorgio Vallortigara from the University of Trieste, Italy, who studies lateralisation in vertebrates, says that the left side of the brain directs approach behaviour and the right side withdrawal. Dogs wag their tail to the right when they see a friendly human but to the left when faced with a scary dominant dog, he found (Current Biology, vol 17, p R200). "The wild fish could similarly use their left eye here because they are frightened and more likely to withdraw," he says.

But there is another explanation, says Brown. Left-eye preference for novel objects in wild fish could mean they have learned to take better advantage of their innate ability to lateralise: "Using the left lobe could simply be the default in this context," Brown says. Indeed, fish from low-predation areas showed a slight tendency to use the right eye in all tasks. Lab-born fish of parents from high-predation areas could be exaggerating this default right-eye bias because they have inherited strong lateralisation. However, since they've never met a predator, they haven't learned to pay special attention to novel objects using their right brain and left eye.

Whether humans with differing life experience also vary in which brain side they use to deal with certain emotive stimuli is not yet known, but the researchers agree that such processing plasticity is likely in all lateralised species: "We know, for example, that stroke patients with damage to one hemisphere can learn to compensate with the other lobe," says Brown. And Vallortigara adds: "I would expect a dog who has never seen a human would feel more sceptical and wag its tail to the left."

Study suggests sonar doesn't harm fish

Science Daily

July 9

A U.S. study suggests high powered sonar, such as used by Navy ships, does not harm fish.

University of Maryland researchers studied rainbow trout housed in an experimental tank at the U.S. Navy Sonar Test Facility in Seneca Lake, N.Y.

Led by biology Professor Arthur Popper and research associate Michele Halvorsen, the scientists found exposure to high intensity, low frequency, sonar did not kill the rainbow trout, nor did it damage their auditory systems, other than for a small and presumably temporary decline in hearing sensitivity.

But Popper cautioned the finding should not be extrapolated to other fish species or the effects of other sound sources.

He said there is considerable concern that human-produced (anthropogenic) sounds added to the environment could have damaging effects on marine life. While much of the interest has focused on marine mammals, such as dolphins and whales, there is growing interest in the effects of such sounds on fish.

"The effects of sound on fish could potentially include increased stress, damage to organs, the circulatory and nervous systems," said Popper.

The study is reported in the July issue of the Journal of the Acoustical Society of America.

Rare fish mysteriously enter man-made pond

It likely took a 1.5-mile joyride through piping but nobody knows for sure

By Melinda Wenner

MSNBC

July 16

Scientists in Southern California have discovered a mysterious booming population of endangered desert pupfish in man-made research ponds designed for an entirely different purpose.

Although no one knows exactly how they got there, the fish probably took a 1.5-mile joyride through the piping used to deliver water to the ponds.

Last year, Douglas Barnum, a scientist with the U.S. Geological Survey’s Salton Sea Science Office, and his colleagues built four small ponds to study how ongoing changes in the Salton Sea — the largest lake in California, which is 25 percent saltier than the ocean — will affect nearby wildlife as part of the state’s ongoing Salton Sea Restoration Project.

The Salton Sea, an important habitat for migratory birds, is slowly drying up and growing saltier. It is also becoming tainted with selenium as it is fed by a number of rivers, including the Alamo River, contaminated by selenium from the upper Colorado basin.

The element, which may be leaching into the basin from agricultural sites, can be toxic to wildlife, especially as it accumulates through the food chain.

“The birds are potentially eating a very toxic time bomb,” Barnum told LiveScience.

To study how birds respond to the growing selenium levels as well as the changes in salinity, the scientists created man-made ponds, mixing the salty water from the Salton Sea with water from the nearby freshwater Alamo River to create a series of four ponds of varying salinity, all slightly contaminated by selenium.

The plan was to study how bird populations respond to the different ponds, which are all carefully filled so as to prevent fish and other wildlife from being pumped in too. The water first travels through a trench with a rock barrier and then continues through one and a half miles of piping until reaching the ponds.

It was therefore surprising when Barnum and his colleagues noticed a number of larger fish swimming around in the ponds this year.

They assumed that all of the fish were a common species known as tilapia and that they had somehow survived the long trip from the lake or river to the ponds. But when they started doing some maintenance work a few weeks ago, they “noticed something that was a little bit odd,” Barnum said.

They saw smaller fish in the ponds, too.

“These were not Tilapia, and they didn’t look like anything else we had seen,” Barnum said.

The tiny fish, they discovered, were actually endangered desert pupfish — populations of which have declined over the course of the past few decades thanks to a loss of habitat and changes in environmental conditions, such as dam-building, according to the U.S. Geological Survey.

The scientists estimate that there are thousands of these endangered fish living in the research ponds, although most of them are young, and no one knows how many will survive into adulthood.

They also aren’t sure whether the pupfish are coming from the Salton Sea or the Alamo River, but it’s likely that they somehow made it through the rock barriers and made the voyage through the piping.

Young pupfish are smaller than a fingernail, so “they may be able to make it through the cracks in the rocks,” said Barnum. “It doesn’t sound possible, but who knows.”

He added that it only takes two pupfish — a male and a female — to start a population. While it could be that pupfish are more prevalent in California’s rivers and lakes than anyone realized, it may also be that a few brave individuals just happened to make it to the ponds and, upon their arrival, mated like mad.

This exciting windfall has prompted the scientists to try to broaden their research goals to include studies of the elusive pupfish as part of their project.

“Let’s take advantage of this golden opportunity to learn something about this endangered species,” said Barnum.

Flattieman.