Friday Fishy News - August 10

[Flattieman]

Hi Raiders,

Woah! I haven't made a post in ages! I've been really busy lately, but I've got a break over this weekend when I can hopefully catch up on all the posts I've missed! Hmm... I'll have a look in the Aquarium first... Enjoy the news!

Giant fish tales could well be true

Research suggests harvesting large fish help what's left become giant

By Dave Mosher

MSNBC, USA

July 30

Three Redfin (Perca fluviatilis) of approximately equal age. The large individuals are "giant cannibals," which can occur if adults are over-fished.

Anglers all have tales about the one that got away, the fish of legendary size that stripped the line from the reel. A new study suggests why that there might indeed be giants and offers an explanation for how they grow so huge.

Turns out fishermen themselves can be responsible for the monsters.

If a lake or pond is overfished, and a lot of the big ones are caught, the situation is ripe for oversized freaks to develop, according to a new computer model.

The research suggests that harvesting only large fish knocks out the food competition for the remaining adults, allowing the adults to gorge on smaller fish and inflate to gigantic proportions. The effect is strongest for fish prone to cannibalizing their own. A Eurasian perch growing in such a situation, for example, can become more than four times as big as an adult fish the same age in a body of water not heavily fished.

"The destabilization of a cannibalistic population can induce the growth of 'cannibalistic giants,'" scientists write in the August edition of the American Naturalist. Further, the population becomes less stable and more susceptible to crashing into extinction, especially as the rate of fishing increases. The giants were not found to develop in the virtual populations spared from harvesting.

The effect also applies to fish species that are not cannibals, but it is less pronounced and does not tend to push the population toward extinction, the computer model suggests.

There could be a useful lesson for fish farmers.

The model accounted for a range of factors, from food availability to reproductive rates and digestion time. When the researchers over-harvested small fish, cannibalistic giants were not produced, but non-cannibalistic fish grew bigger, faster — a technique that fish farms could use to grow market-ready crops more quickly.

The work was led by Tobias van Kooten of Umea University, in Umea, Sweden.

Jaws, Teeth of Earliest Bony Fish Discovered

By John Roach

National Geographic News

August 1

Fossils of sardine-size fish that swam in ancient oceans are the earliest examples of vertebrates with teeth that grow from their jawbones, according to new a new study.

The fish, which lived 420 million years ago, are a "very modest" beginning for the jaw-and-tooth pattern widespread in nature today, said study co-author Philippe Janvier, a paleontologist at the National Museum of Natural History in Paris, France.

"It's really the first evidence that we have of the earliest bony fishes—the earliest ancestors of all the fishes that have the[ir] bones and teeth implanted in the bones of the jaw," Janvier said.

Modern bony fish such as cod, herring, and coelacanths have this tooth arrangement. So do tetrapods—four-limbed creatures such as frogs, crocodiles, and humans, which are all descendants of bony fishes.

When a bony fish or a tetrapod loses a tooth, a new one grows from the bone below the void, whereas other jawed vertebrates, such as sharks, have teeth that grow from inside their gums. Sharks have skeletons of cartilage instead of bone.

Shark teeth are lined up in "families." New teeth grow at the inner end of their respective tooth family, and old teeth fall off at the end of an inside-out progression—similar to a conveyor belt.

Though fossil representatives of the earliest members of each of these living groups are well known, the earliest stages of jawed vertebrate evolution presents a fuzzier picture.

The new fossils help clarify these questions, Janvier said.

Transition Fossils

The researchers discovered the telltale bony fish fossils among fragments collected on the Swedish island of Gotland in the Baltic Sea. Other fragments came from boulders carried to Germany by glaciers a few million years ago.

Some of the fossils belong to the species Andreolepis hedei and others to Lophosteus superbus, fish previously identified by scale and head bone specimens.

Whether they were truly bony fish or more like sharks was an open question, however.

Two of the new fossils suggest a direct link to bony fish: tooth-bearing jawbones.

What's more, the bones show a tooth pattern that is in between the tooth rows of sharks and bony fishes.

Though these ancient bony fish teeth grew from a bone, old teeth remained attached to the bone. New, larger teeth grew at the inner end of each tooth file.

"It shows a sort of transition between the shark condition and the bony fish condition," Janvier said.

Within 20 million years after Andreolepis hedei and Lophosteus superbus lived, the first bony fish with much larger teeth characteristic of modern bony fish and tetrapods appear in the fossil record. This was during the Devonian period, 416 to 359 million years ago.

"That's very important because it allowed the bony fishes to become predators," Janvier said.

Sharks also existed in the Devonian, but they were "humble compared to the bony fishes," he said.

The first bony fishes probably ruled the seas, rather than sharks, because the bony fishes' teeth lasted a longer time in the jaw.

"Then, later on, the sharks ... became much larger and big predators," Janvier added.

The study appears in tomorrow's issue of the journal Nature.

Sorting Characteristics

Michael Coates, a biologist at the University of Chicago in Illinois who studies early vertebrate evolution, was not part of the research team.

He said the discovery of rare fossils like the ancient bony fish allows scientists to sort general, primitive characteristics of all jawed vertebrates from the more specialized features that distinguish sharks from bony fishes.

The new study, he noted, clearly shows that Andreolepis and Lophosteus are bony fishes, but their tooth pattern raises a question about what makes a shark a shark.

"Growing teeth in this serial manner around the jaw margin—which once upon a time looked like it was unique to sharks—now looks like it is a general system."

Marine census details bluefin tuna decline

Science Daily

August 8

Scientists involved with the Census of Marine Life project have detailed the collapse of the bluefin tuna population off northern Europe.

The research shows before World War I, Atlantic bluefins were rarely captured and even coastal sightings were exciting events. One bluefin measuring nearly 9 feet in length washed ashore in Germany in 1903. Those captured during the 1920s weighed as much as 1,550 pounds.

After World War I, burgeoning quantities of tuna were caught. Major tuna fishing countries at the time -- such as Norway, Denmark, Sweden and Germany -- that recorded virtually no bluefin landings in 1910, reported nearly 5,500 tons by 1949.

Scientists said such booming catches helped strip the Atlantic bluefin population in a very short time, with the species virtually disappearing during the early 1960s.

The Census of Marine Life, based in Washington, is a global network of researchers in more than 80 nations engaged in a 10-year initiative to assess and explain the diversity, distribution, and abundance of marine life in the oceans. The network will release the first Census of Marine Life in 2010.

The bluefin study is to appear in a special issue of the journal Fisheries Research.

Fishing as a Contact Sport

In Missouri, Catfish Grabbers Fight Fish and the Law

By Jung H. Song and John Berman

ABC News, USA

July 29

ABC News correspondent John Berman holds a catfish. Missouri has banned fishing with your hands, also called noodling, on the cusp of the third noodling season.

In the wild, wild Midwest, people who call themselves "noodlers" are catching massive catfish with their bare hands, using their own fingers and toes as bait.

A seasoned "noodler" from Missouri, Howard Ramsey, proudly displays his scarred arms and digits, called "river rash" by insiders.

"Yep, that's right, " he beams, "You gotta bleed."

Noodling, which began with Native Americans, is the art of catching catfish with your bare hands. People like Howard Ramsey have done it for years without rod, hook or bait. Instead, they quietly grope the dark undersides of rocks or stumps in riverbanks, where catfish nest, until they feel the sandpaper-like teeth of catfish clamp down on their hands.

Then, the noodler grips the jaws and triumphantly yanks the writhing fish to the surface. Ideally, that is.

Sometimes, noodlers poking around the mossy, underwater crevices are also vulnerable to the painful bites of snapping turtles, snakes and beavers that may hole up in abandoned catfish nests.

Noodling old-timer Ramsey quipped to ABC News' John Berman, "Webster's [dictionary] describes a noodle as 'a crazy person.' Just about anybody you talk to thinks you got to be crazy to do this."

The idea of noodling may be laughable, but hand fishing enthusiasts say it's usually a fair fight. Fish can weigh up to 100 pounds, and many say what they like most about the sport is meeting the fish on its own turf and terms.

Banned since 1919 for disturbing the natural food chain, noodling came back to Missouri two years ago after Ramsey and the fishing fanatics of "Noodlers Anonymous" fought for the right to hand fish on a trial basis for five years. During a six-week annual season, noodlers could nab up to five fish per day in three of the state's rivers.

Their hook-and-line counterparts are allowed a daily catch of 20 fish, 365 days a year.

But this summer, right on the cusp of the third legal noodling season, the Missouri Department of Conservation banned hand fishing once again. The Department said 646 catfish had been caught even before the noodling season began, and fisheries division chief Steve Eder reported that scientists had found higher-than-expected mortality rates among the state's catfish.

Noodling is legal in at least thirteen Midwestern and Southeastern states, including Louisiana, Mississippi and, recently, Georgia. The greatest homage to the sport, however, takes place in Nigeria at the Argungu Festival, where 10,000 fishermen jump into opaque, coffee-colored streams to wrestle giant freshwater perch.

Though Missourian noodlers claim they are being singled out, a Department of Conservation FAQ sheet explains that hand fishing targets the largest of the breeding fish, as well as their nests. Snatching a parent may leave thousands of catfish eggs vulnerable to predators.

In response, desperate noodlers have offered to cut down their bounty to just five catfish per season, significantly reduced from their previous quota of five per day -- but the Missouri Department of Conservation just isn't biting.

Noodlers have vowed to take their case to the state legislature.

Fish bans raise poison risk

By Selina Mitchell and Lauren Wilson

The Australian

August 4

The protection of Australia's fisheries is pushing seafood imports to record levels, driving overfishing in other countries and exposing consumers to unacceptable levels of antibiotics and other contaminants.

Marine biologist Walter Starck said Australians were being forced to consume lower quality seafood imports, many from seriously depleted fisheries, even though Australia had a relative abundance in some species that was being underutilised.

Dr Starck's warning comes amid increasing concerns about contamination of imported seafood products.

Federal Fisheries Minister Peter McGauran revealed this week that tests conducted by Australia's quarantine watchdog had found small residues of banned antibiotics in one-third of the samples of prawns, fish, crabs and eels from China, Indonesia, Vietnam and Thailand.

Amid fears that contaminated seafood could generate a new breed of antibiotic-resistant superbugs, the federal Government has promised to strengthen the testing of imported produce.

But it has agreed only to add more antibiotics to the list of substances that are tested, rather than increase the actual amount of testing of imported fish. Just 5per cent of seafood imported to Australia will be checked for banned antibiotics and pesticides, despite the test findings.

Consumer concerns about the imported seafood follow recent revelations about dangerous substances in imports of manufactured goods.

Toymaker Mattel recalled 24 Fisher-Price character toys this week after they were found to contain potentially harmful levels of lead in the surface paint applied during the manufacturing process in China. And two brands of Chinese blankets were recalled nationally last month after they were found to contain high levels of carcinogenic chemicals.

About 70 per cent of Australia's annual seafood consumption is imported after a long-running program of cutting the national fishing fleet.

About one-third of commercial fishermen handed their licences back last year after a buyback cut 550 permits from the nation's 1600 commercial fishing licences.

Australian fisheries are widely regarded as well managed, with the buyback considered necessary to ensure the fishing industry is sustainable.

But Dr Starck said while certain species were clearly endangered and needed to be tightly protected, the current scale of regulation in Australian fisheries was focused on the unqualified conservation of marine environments rather than the sustainable management of fish stocks.

He said it was now costing taxpayers $100,000 each year to manage each boat in the national fleet, even though Australia had the largest fishery per capita in the world. "The idea that our fisheries are in danger of overfishing as a blanket statement is ridiculous," he said.

"If we want to import all of our fish, we can do that and that is basically what we are doing. If we applied the same rules to our agriculture and grazing, we'd have to close them down."

Australia imported $1.03 billion worth of edible fish and seafood in 2005-06 -- up from $905million in 2003-04. The fastest growth was in products from Vietnam and China, which with Thailand now account for more than half of total seafood imports.

Despite the recent discovery of antibiotics in imported seafood, Mr McGauran has moved to assure people of its safety. He said while the residues detected were at low levels and did not represent a food safety issue, there would be extra testing to give consumers greater confidence in supplies.

In June, the US Food and Drug Administration imposed increased testing on Chinese farm-raised seafood -- including prawns, basa (Vietnamese catfish) and eels -- after finding produce repeatedly contaminated with banned antibiotics.

The Australian Government introduced random testing of 5per cent of imports in 2001. But Labor has been pushing for more widespread testing, covering a greater range of chemicals and antibiotics.

The Australian Quarantine and Inspection Service surveyed 100 samples of imported fish, crabs, eels and prawns for chemical residues from April last year to March this year.

The samples were screened against 39 antimicrobial and 49 pesticide compounds. There were no pesticide residues detected but 14 antimicrobial chemicals were detected at low levels. The chemicals belong to the sulphonamides, tetracyclines, malachite green, penicillin, quinolones, fluoroquinolones and phenicols antimicrobial chemical groups.

The National Health and Medical Research Council is investigating the issue of microbial resistance, but will not report for several months.

Peter Collignon, director of microbiology and infectious diseases at the Australian National University medical school, said the test results were worrying.

"What this means is antibiotics were used in the production of those fish or prawns. That means superbugs can develop and they can remain on the animal and come across to people and cause problems," he told ABC Radio.

Of the 20 fish retailers contacted by The Weekend Australian yesterday, none believed strengthened testing measures would benefit Australia's seafood industry.

All food imported and sold locally must be labelled with its country of origin, but consumer group Choice yesterday questioned whether the rule on labelling was being properly policed. Choice recommended that if people were worried about their safety, they should ask where the seafood had come from.

Antibiotics can be used in production but all traces should be gone by the time the seafood is harvested for market.

AQIS spokesman Carson Creagh said the test results released by the minister this week had been passed on to Food Standards Australia New Zealand and the national Health and Medical Research Council for expert advice.

The Australian fishing industry blames an unfair playing field, including tight government regulation, for forcing local producers to charge more for their safe, wild-caught seafood while competitors intensively farm fish in other countries.

The use of antibiotics overseas was a concern, but many consumers could not afford higher prices for local fish.

"The quality of the product going out of the country is strictly monitored but the product coming in is not so carefully watched," Western Australia's Fishing Industry Council chief executive Graeme Stewart said yesterday.

But Harry Peters, the president of the Australian Seafood Industry Import Association, said imported produce was subject to rigorous testing. He said Australia did not have a problem with contaminated imported seafood: "Australia has always had a zero-tolerance policy when it comes to ensuring our imported seafood isn't affected."

China is struggling to contain fears that some of its exporters have cut corners, making their products unsafe.

A recent report by China's Administration of Quality Supervision, Inspection and Quarantine claims more than 99 per cent of Chinese food exports met all criteria. But the Government is responding to fears about the other 1 per cent -- especially because of fast-growing anxiety within China about food and drug safety.

The minister in charge of food safety, Li Changjiang, said China was "addressing the fundamental causes" behind the range of problems with exports, which have included toothpaste containing antifreeze and snack foods with salmonella.

He admitted that US complaints about farmed fish and shellfish containing banned antibiotics were correct, and that in some cases seafood had even been exported as antibiotics -- which the fish contained -- to evade inspection.

'Living Fossil' Fish Hooked in Asia

By Ronan Bourhis

Discovery Channel

July 31

Two months ago an Indonesian fisherman caught a fish so exceptional that an international team of scientists rushed there to investigate.

French experts equipped with sonar and GPS asked the fisherman, Justinus Lahama, to reconstruct in his dugout canoe,exactly what it was he did to catch a rare coelacanth, an awkward-swimming species among the world's oldest.

"I very quickly unrolled the usual trawl line with three hooks, about 110 yards long, and at the end of three minutes, I felt a large catch," Lahama recounted.

After 30 minutes of effort under the searing tropical sun, he finally saw a fish swishing at a depth of about 65 feet.

He thought he was dreaming, he said, when he saw the creature at the end of his line.

"It was an enormous fish. It had phosphorescent green eyes and legs. If I had pulled it up during the night, I would have been afraid and I would have thrown it back in," he exclaims.

After spending 30 minutes out of water, the fish, still alive, was placed in a netted pool in front of a restaurant at the edge of the sea. It survived for 17 hours.

Coelacanths, closely related to lungfish, usually live at depths of 656-3,200 feet. They can grow up to 6.5 feet in length and weigh as much as 200 pounds.

Lahama, 48, has fished since he was 10-years-old, like his father and his grandfather before him. But he was unlikely to have ever run into this "living fossil" species, as scientists have dubbed the enigmatic fish.

Lahama's catch, weighing 110 pounds, was only the second ever captured alive in Asia. The first was caught in 1998, also off the Indonesian coastal city of Manado.

That catch astonished ichtyologists, who until then had been convinced that the last coelacanths were found only off eastern Africa, mainly in the Comoros archipelago. They had been thought to have died out around the time dinosaurs became extinct, until one was found there in 1938.

Their fossil records date back more than 360 million years and suggest that the fish has changed little over that period.

Can Shortnose Sturgeon Fish Survive?

Science Daily

August 7

Dwindling numbers of shortnose sturgeon in Georgia's blackwater Ogeechee River system have prompted an effort to quantify the causes and prioritize recovery efforts.

Yetta Jager and colleagues at Oak Ridge National Laboratory are conducting a population viability analysis, which will provide a scientific basis for assessing cumulative and separate effects of factors thought to be impacting the shortnose sturgeon population.

These factors include siltation of spawning areas, degradation of water quality in summer due to upstream agriculture, urban development and military land management, atmospheric mercury and introduction of saline water introduction through rice canals.

While 19 distinct populations of shortnose sturgeon have been identified in coastal rivers, only two southern populations are thought to be viable. The Ogeechee population has fewer than 500 fish.

Jager is working in cooperation with field efforts conducted by Fort Stewart and Doug Peterson at the University of Georgia in this three-year project, which is funded through the Strategic Environmental Research and Development Program.

Fish stunned during flood rescue

BBC News

July 31

A current of electricity is passed through the water

Thousands of fish stranded by floods are being stunned with electricity as part of efforts to rescue them.

The fish have been trapped at the flooded racecourse in Worcester.

The Environment Agency said the oxygen levels have been dropping out of the water quickly so the fish would die if they were not helped now.

Electricity is passed through the water before the fish are collected in nets and tanks to be stored until they can be put back in the water later.

Carp, bream and eel are among the types found so far.

'More adventurous'

David Throup, from the Environment Agency, said it was a race against time.

He said: "It's the second time it's happened with the summer floods.

"What usually happens in the winter is the fish are quite torpid. They're quite slow and they tend to roll back in the river when the waters go down.

"In the summer they're more adventurous and they're looking for somewhere to spawn, somewhere to feed, so they go out across the flood plain."

He said the agency would try to deal with the larger fish on Tuesday evening and intended to return on Wednesday to help the smaller fish.

Thief battered in fish shop

IOL - South Africa

July 30

A man who attempted to rob an Australian fish and chips shop found himself on the losing side when the angry shop owner threw fish batter and hot oil at him.

"The hot oil missed but the batter hit the offender and he fled empty handed," South Australian police said in a statement.

Police said the attempted armed robbery happened on Thursday evening at the quiet seaside retirement town of Victor Harbour, near the South Australian state capital of Adelaide.

Police were checking local hospitals in case the man was injured.

Flattieman.

[mrmoshe]

Welcome back Flattieman...We missed you.

Some good reads in there this week Ryan.

Cheers,

Pete.

[Flattieman]

Welcome back Flattieman...We missed you.

Some good reads in there this week Ryan.

Cheers,

Pete.

Thanks, mate. As you've probably noticed, I'm still really busy and don't have a lot of time for FR, but it is good to be posting the news regularly at least .

Flattieman.