mrmoshe
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Secrets of the seas: Jurassic shrimp, hairy crabs and giant microbes
Ambitious project is finding two species of fish each week unknown to science
Ian Sample, science correspondent
Monday December 11, 2006
The Guardian
An ambitious attempt to draw up a census of life beneath the waves has revealed a clutch of exotic species and a shoal of fish which is the size of Manhattan island.
Research vessels dispatched to probe the depths of the world's oceans stumbled across an ancient shrimp, previously known only from fossil records, which was thought to have become extinct 50m years ago.
Nicknamed Jurassic shrimp, the creature was spotted on a sea mount near the Philippines and rivals the discovery of the coelacanth, a prehistoric fish now known to populate the waters off South Africa and Indonesia.
Scientists aboard another research vessel looking for life in the Nazare canyon in the sea off Portugal's coast spotted giant fragile microbes which protected themselves with plate-like shells made from mineral grains.
Other finds included the hairiest crab ever documented and a vibrant community of jellyfish and other creatures lurking in some of the darkest waters known, discovered when scientists drilled a hole through 700 metres (2,300ft) of Antarctic ice and lowered a camera into the depths.
The census was launched in 2001 to map life in the most under-explored environment on earth and uses half of the world's large research vessels and submersibles. Destined to finish in 2010, the £500m project involves 1,700 scientists in 73 countries.
"By 2010 we'll have a representative picture of what lives in the oceans from top to bottom and around the world," said Ron O'Dor, senior scientist on the project. "Everywhere we go we find more life than we'd imagined. When we started there were views that as you went deeper the oceans turned into deserts and there was nothing living down there, but that certainly isn't true."
The discoveries have been coming to the surface at the rate of two species of fish unknown to science each week. And the scientists believe that they are still far from documenting all the different marine species. Advanced sonar equipment that can map oceanic areas 10,000 times larger than previously possible recently detected a shoal of eight million fish in a school the size of Manhattan off the coast of New Jersey. Images of the shoal revealed it pulsating, fragmenting and reforming as the fish moved through the water.
When the census is completed it will form a snapshot of ocean life that scientists will use as a reference to monitor the impact of the fishing industry and environmental change, such as global warming.
The ships include a German icebreaker, the Polarstern, the world's most expensive research vessel. The ship is now in Antarctic waters testing for life on a seabed that recently became exposed after a vast slab of ice broke free from the continent.
Scientists have mounted 19 other ocean expeditions this year and tagged more than 20 species, including sharks, squid, sealions and albatrosses, with tiny radio transmitters that feed back information on migration patterns and ocean currents. One bluefin tuna tagged with a transmitter stunned scientists by making three crossings of the Pacific in 600 days, covering a distance greater than the earth's circumference.
Tracking fish has revealed some uncomfortable truths for those managing fish stocks. Computer models of fish abundance have proved, in many cases, to be too simplistic and have failed to recognise that many key breeding grounds have been knocked out by over-fishing. The backlog of the freshly discovered species is gradually being put into order, short sequences of cell DNA serving as the "bar codes". So far, more than 4,000 DNA tags have been recorded in the census database.
David Farmer, an oceanographer at the University of Rhode Island, who is involved with the census, said: "I find it hard to believe that what the census is finding is going to be more than a tiny fraction but it is surely a pioneering contribution. This is going to be immensely valuable. Not being put off by the magnitude of the task, and nevertheless pushing on and bringing it all together, is astonishing."
New wave: Emerging facts about the oceans
· The world's oceans are 70% shark free and sharks rarely colonise water below 3,000 metres (about 9,800 ft, or into the oceanic abyss). As they are concentrated quite near the surface the animals are vulnerable to being caught in nets
· Eight million fish were observed off the New Jersey coast in a shoal bigger than the area of Manhattan island
· Scientists thought Neoglyphea neocaledonica, the "Jurassic shrimp", had become extinct 50m years ago, but it was found on an underwater peak in the Coral Sea, north-east of Australia
· Sooty shearwaters can fly 43,496 miles in search of food, carving out a figure of eight around the Pacific Ocean. Electronically tracked migrations revealed that in only 200 days some birds clocked up a daily average of nearly 220 miles
· The team found a half-metre, spiny lobster off the coast of Madagascar weighing 1.8kg (3.9lb)
· Near Easter Island researchers found a creature so strange they had to classify it as being within a new biological family. The crab Kiwa hirsuta is named after its own hairiness and the Polynesian goddess of shellfish
· Temperatures around deep, hot vents can range from 2C to 407C (764F) in the space of a few centimetres. Some species such as shrimps can survive here
· The oceans contain an estimated 5m to 10m species of bacteria. The figure comes from sampling water at various locations and using DNA techniques. One litre of sea water can contain 20,000 different species of bacteria
· Less than 2% of coral reefs are in marine protected areas and are vulnerable to poaching and coral extraction
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Top effort fellas...I would have loved to see that YFT scoffed by the bluey.
What an awesome sight that must have been.
Well done.
Cheers,
Pete.
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Very nice striper Steve. Congrats to the young-un on his first and for the first beakie for the boat.
Looks like they have arrived for the season.
Cheers,
Pete.
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Well done Ryan. Who said brains and fishing don't mix eh?
A wonderful achievement to be Dux of the Year. Three in a row too.
Keep up the great work.
Cheers,
Pete.
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i think I'd use it as a down payment to rent Reg Grundy's super yacht that is berthed at Garden Island at the moment.
He only wants US$490,000 a week for it too!!!
He's here with his wife for a book launch and this craft boasts some impressive credentials.
Cop this for opulance:
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Delivered in 1999 by Amels, this yacht offers superb facilities for entertaining and long distance cruising. An elegant Terence Disdale interior incorporates accommodation for up to 12 guests in 5 doubles and 2 twin cabins plus a limited number of staff (upon request). The living areas are numerous including 2 salons, an observation lounge, 2 formal dining areas and a breakfast bar gallery. Each area is cleverly divided up into cosy rooms, creating an intimate atmosphere despite being on a yacht of over 70 meters in length. An authentic cinema with 14 seats and a stage together with vast deck areas, including a beautiful tiled swimming pool (with jet stream) on the sundeck, complete the picture.
Tender and Toys:
1x 26ft custom jet boat with 115hp engine · 1x 29ft tender with 115hp engine · 2x 18ft Ribtec Jet landing crafts with 100hp engine · 2x 700cc Yamaha waverunnners (2 man) · 4x windsurfers · 1x Laser sailing dinghies · 1x 2-man kayak · 2x single kayaks · waterskis & tows · fishing gear · snorkelling gear
Entertainment:
· televisions, videos & DVD · Cinema with 14 seats and stage · satellite television · stereo music systems · piano · swimming pool with jet current · gymnasium · barbecue
Engines
2x 2600hp
.............................................................................................
I wonder if they'd let me bring my smelly bait bucket aboard!!
If you are keen..you can rent it when he's not using it.
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Well done Brett...damn nice dollie there.
He must have been a handfull fighting that beasty.
Good on you.
Pete.
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Very nice haul there Ewan. Must have been fun latching onto them today.
The swell must have been something else out there too...glad you didn't hurly burley too much.
Bodes well for the rest of summer having spotted macs around this early.
You should enter them into the fish of the month comp.
Nice report too.
Cheers,
Pete.
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A pity Bill that you didn't make it to Camp Fishraider. You should have yelled out and a few of us could have helped you hold the boat while you registered.
Yes, it wasn't the best weather but more than made up for it by meeting everyone there and sharing a few
and a feed. That flattie you got may have taken out a prize in the end, but not the major one..It was unbeatable the moment it hit the deck.
Glad you got a feed in the end so it wasn't a total loss.
Let's hope you can make the next social for kingies on the harbour.
Cheers,
Pete
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Amazing stuff eh? And I thought levitation was just in side shows etc.
It probably has a good application when they figure out what to do with it.
Pete.
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Nice brace of flatties there.
Gee, that slimy sure copped the business end of something toothy.
I wonder if it was a hoodlum king.
Enjoy your feed tonight.
Pete.
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Sydney fishing ban partially lifted
A ban on recreational fishing in Sydney Harbour has been partially lifted.
Dangerously high levels of dioxins found in fish caught in the harbour and Parramatta River forced the ban early this year.
News Ltd reports that anglers can now take home fish caught east of the Harbour Bridge.
However, the Parramatta River is still too contaminated.
Fisheries Minister Ian Macdonald told News Ltd "the situation west of the bridge is bleak and anglers should release their catch".
More info from ABC Online:
Sydney Harbour fishing ban partially lifted
Recreational fisherman will be able to eat their catch in a section of Sydney Harbour again, after tests confirmed safe dioxin levels.
The New South Wales Government says the levels are now safe east of the Harbour Bridge.
A ban remains in place for the Parramatta River and on all commercial fishing throughout the Harbour.
Primary Industries Minister Ian Macdonald says tests conducted on 400 fish have confirmed safe dioxin levels east of the bridge.
"The overall picture for recreational fishers is you can consume some of your favourite targeted species - such as kingfish, trevally, some species of whiting and consume up to 1.8 kilograms per month of those species," he said.
More:
From The West Australian
Dioxin ban lifted on some Sydney fish
Recreational fishers can now eat greater quantities of their catches from some sections of Sydney Harbour.
The NSW government had previously advised anglers to eat only 150g of fish or 300g of prawns a month if they were caught east of the Sydney Harbour Bridge due to dioxin levels.
However, recent tests have shown it is now safe to eat greater quantities of six recreational species, including up to 1.8kg a month of kingfish, luderick, flounder and trumpeter whiting.
It is also safe to consume up to 1.2kg a month of sand whiting and 750g of silver trevally and crab.
Primary Industries Minister Ian Macdonald said fish caught west of the Sydney Harbour Bridge was still unsafe to eat and should be released if caught.
"Fishers who are unsure of what type of fish they are catching should follow the current dietary advice of 150 grams a month," Mr Macdonald said.
He said commercial fishing in Sydney Harbour would remain banned in the foreseeable future, with commercial species such as bream, prawns and squid still containing high dioxin levels.
NSW Opposition Leader Peter Debnam said years of government inaction meant recreational anglers could only eat certain types of fish caught in specific parts of the harbour.
"The government's announcement simply affects the harbour east of the bridge," Mr Debnam said.
"We're left with a situation that, because this government didn't clean up the dioxins over the last decade, you've got a major pollution problem in the Sydney Harbour west of the bridge."
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Australia's fishing sanctions 'illegal'
From ABC Online
A legal expert has warned changes that sanction the Navy to fire on illegal fishing boats are illegal under international law.
The measures, announced by Defence Minister Brendan Nelson this week, allow the Navy to fire into the bow or engine of foreign fishing boats in Australian waters if they ignore calls to stop.
University of Queensland expert Dr Rachel Baird says the International Tribunal for the Law of the Sea has ruled that the use of such force is excessive.
She says firing into vessels could leave the Navy open to retaliation.
"The consequences of firing into the flag vessel of another state are that you could first of all injure the national of that other state or even kill the national of another state," she said.
"The extreme consequence is that the Australian Government could be subject to international legal action for that action."
Dr Baird says the Government should concentrate on stopping the boats before they arrive by targeting their owners and the markets that sell their catches.
"The problem with shooting into the vessel is that you can't see whether there's anybody in the area of the vessel that you're shooting into and the risk of injury to the national of a foreign state is incredibly high," she said.
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Hi Dan,
There is nothing on the Fisheries website to say crabbing is illegal in M.H.
I guess as long as you follow the rules, you should be OK.
__________________________________________________
Hoop or Lift Net (commonly called Witch's Hat):
Crab net
*
* Not more than 5 nets to be used (or in possession) by any person at any one time.
* 1 or 2 hoops per net (no rigid frame between them).
* Diameter of hoops should be no greater than 1.25 metres.
* Mesh size not less than - 13mm.
* Drop (length of net) should be no more than 1 metre.
* A tag, at least 80mm x 25mm, clearing showing your name and address (or name and registration number of boat being used) must be attached.
* Must be dropped and raised vertically through the water by hand.
* Must not be used in ocean waters.
* Any rock lobsters or fin-fish (which are subject to a size limit) which are caught must be returned to the water.
_____________________________________________________
As for eating them, (personally, I wouldn't risk it) I guess the same caution should be used as bream etc.(ie:Dioxins etc)
It's up to you, but one or two eaten now & then should be alright. I just wouldn't make a habit of it.
Others may have differing views.
Cheers,
Pete.
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Loved the levitating fish story Flattieman.
My only question would be...Why?
Perhaps they can levitate them onto my hook one day.
Cheers,
Pete.
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One and all.
Looking forward to reading of your fishing adventures.
Don't be afraid to ask questions of the members. We are a very
helpful bunch on here.
Cheers,'
Pete.
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Fisherman's finger chopped off
A FISHERMAN has been flown to a Tasmanian hospital after his finger was chopped off.
The 45-year-old man “severed a finger on his left hand whilst commercially fishing for rock lobster”, Tasmanian Police Inspector Darren Hopkins said.
The accident occurred just after 7pm (AEDT) today at Low Rocky Point, south of Strahan on Tasmania's remote west coast.
A satellite phone was used to alert emergency services.
“The Westpac Police Rescue Helicopter was tasked and airlifted the male from the area at 9pm to the Royal Hobart Hospital,” Insp Hopkins said.
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Hey Stewy..what's Fred like at stuffing catfish?
You could keep him busy for months!
Cheers in jest,
Pete.
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Thanks for the picture Pete, certainly looks like the lake is draining well.
Can you confirm whether it is possible to walk across the opening?
Look forward to hearing about your fishing in the coming days/weeks, to see if it picks up rapidly.
Does this mean you have to change your fishing tactics at your secret spot?
yes, you can walk across the entrance. The opening is on a rock bed and is very stable. The water rushing out might make it a bit tricky...probably best to cross it at slack tide.
I went down today for a session. Started near the entrance using the old faithful whitebait as well as live nippers.
All I got was 6 underweight bream though. After that, I went around to my secret spot and managed another 8 barely legal bream..no flatties wanted to play today.
I got to talking to a local resident near the mouth and he told me there were 15 or so fishos fishing the entrance last night, when the Fisheries Inspectors swooped. They fined more than half of them for not having licences.
Odd though..they let them keep on fishing after they issued the fines..Isn't that a little strange?Great to see the Fisheries policing the area. It might also stop the idiots who take small bream for fishcakes.
The lake level was down today by about 10cm as it was still a run out tide. I can't see much water coming back in the lake until the seas pick up a bit though. You can see the level of the lake is far greater than the sea level just by standing near the entrance.
Going to hit the lake more often in the future.
Cheers,
Pete.
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Hi all
I received the following repy this morning....
It appears that the 'growths' in your flathead are likely to be cysts formed by a microspridian parasite. They certainly look very similar to some photos which have been published in journal articles which show 'white cysts, grossly visible' on the gills arches of the inffected fish.
There are many species of such parasites which infect marine fish (and most other members of the animal kingdom, including insects, reptiles and even humans in some cases) and they usually occur in a specific tissue (e.g. the intestine, stomach or as in the case of your fish, the gills and / or buccal cavity). Microspridia are very small, primitive true-celled organisms, which are not really well known to science. I have come across quite a few examples reported for fish, and generally the infection does not seem to be deleterious to the host organism (unless they are stressed in some other way, e.g. by temperature stress or lack of food). Although some types of microsporidians infect humans, they appear to be fairly host specific and so do not present a danger to humans consuming the flesh of an infected fish (especially if the flesh is cooked first).
To confirm that the growths are indeed such cysts would require histological examination using a microscope, which is not in our normal line of work here and would probably need to be done at the Museum or a parisitology department of a University. The occureence of one (or a small number of) infected fish in Lake Macquarie is not something to be concerned about - however if you come across many infected fish within a catch they that may require further investigation.
Hope this information helps - please contact me again if you require any further information.
This is the 1st of these growths that I have seen. I will have to keep an eye out tyo see if we come across any more
Good stuff Jethro. Glad we all finally have an answer to the riddle of the poxy gills.
Good to know also that it isn't going to make you sick if you eat the fish too.
I hope your fish was a one off and that Lake Mac is still disease free.
Cheers,
Pete.
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Illegal fishermen crowding WA prisons: report
From ABC Online:
A new report says Western Australia's prison system has been flooded with Indonesian fishermen.
WA's inspector of custodial services, Richard Harding, says the state's prisons are stretched to the limit, and could not cope with another influx of Indonesian men convicted of illegal fishing in Australian waters.
He says although the situation has eased recently, the number of Indonesian fishermen is expected to rise again once the cyclone season has passed.
Illegal fishermen are technically Commonwealth prisoners but they are required to be held in state facilities.
Professor Harding says the Federal Government has given a verbal assurance that further illegal fishermen will be detained in Commonwealth facilities in South Australia and the Northern Territory.
He says the influx of fishermen is adding to overcrowding of prisons and impacting on good management.
The comments are contained in a report on the Albany Regional Prison following an inspection earlier this year.
Professor Harding says he will watch closely to ensure the Federal Government keeps its promise to detain future illegal fishermen in Commonwealth facilities.
"Now that's a very important undertaking and it's very important we keep them to it," he said.
"Because this system in WA generally is actually stretched almost to breaking point and we can't afford unnecessary extra overcrowding because of the influx of such people."
Professor Harding says the promise must be kept.
"We'll certainly be keeping an eye on it and making a noise if they don't," he said.
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Sea of Information
Advances in tagging technology help scientists monitor and protect fish populations
Riding piggyback on advances in computing, electronic tags placed on marine animals are increasing our knowledge of the oceans and its many denizens at a dizzying speed.
A new generation of electronic tags, using ever-smaller, off-the-shelf microchips, have allowed marine biologists to learn what fish do under water—not only how deep they go and how often, but also how far they travel and how fast.
“We’ve seen an explosion of knowledge in the past 10 years,” says Ellen Pikitch, the director of the Pew Institute for Ocean Science in Miami.
“Tags have given us insights into movement patterns in animals that were almost impossible to observe,” adds Kim Holland, who heads the Hawai‘i Institute of Marine Biology Shark Research Group in Kane‘ohe Bay.
Some tags, which ping underwater, allow an observer at a console to follow a fish for several days, knowing when it dives and when it rises. Others accumulate data for years—but must be recovered. The latest type allows scientists to receive the data via e-mail once the tag has transmitted it to a satellite.
The information not only has brought startling new insights to marine biologists, but is opening up new avenues for achieving a goal that unites commercial fishermen, conservationists and scientists: how to reduce by-catch, the living creatures unintentionally killed by fishing gear and usually discarded.
The technology is poised to take another giant leap forward by the end of this decade by allowing tags to download each other’s data, then transmit them to a satellite or an underwater listening station, turning a torrent of new information on the ocean depths into a flood.
reducing by-catch
The first tags date from the 1950s and were called streamer or spaghetti tags. They were implanted on the outside of fish and simply recorded where and when the tag was placed. When the fish was caught, it was therefore possible to infer how far the fish had traveled. They are still widely used today to estimate fish stocks.
The first generation of electronic tags was acoustic. By pinging at regular intervals, they allowed scientists listening to hydrophones to follow the fish for a few days and to know how deep they dived (the deeper the dive, the longer the intervals between beeps) and how far they swam. These tags disclosed that many fishes dived deeper and longer than anyone had expected, and that they inhabited different layers of the ocean.
Holland used pressure-sensitive acoustic tags to determine that juvenile tuna that congregate around buoys placed by fishermen to attract fish occupy different depths according to their size. The larger ones live deeper than the smaller ones.
“Juvenile by-catch is the biggest problem faced by the tuna fishery,” he says. “More than half of the tuna caught today are caught in purse seine nets around these buoys. If we can prove to fishermen that it’s in their interest to design a net that will leave the younger fish they don’t want, then someone might design a net to do just that.”
Acoustic tags saved Hawaiian tiger sharks, which are responsible for virtually all shark attacks in Hawai‘i, more than a decade ago, adds Holland. In the 1990s, tags proved that these sharks are constantly on the move, traveling from one end of the archipelago to the other. “Until then, whenever there was a shark attack, entire flotillas would go out and fish as many sharks as they could, because they thought they could catch the attacker,” he says. “Once we showed them that the likelihood of catching that particular fish in the same place the next day was about zero, the practice stopped.”
Meanwhile, another set of radio tags transmitting to the Argos satellite system were placed on turtles, seals and whales. “Tags are the most important thing that’s ever happened in whale biology because what we knew of them was only from their appearance at the surface,” says Bruce Mate, director of the marine mammal program at Oregon State University and a leading whale biologist.
The information proved useful far beyond the biology class. “Most whale populations are kept in check from recovery by human activities, and tags are showing ways to minimize that,” he says.
Case in point: the North Atlantic population of right whales is only 350 strong and has been for three decades. Tags showed that many were getting killed or injured by ships outside Provincetown because the shipping lane passed over a deep trench that the whales feed in.
“Our data was so compelling that…years ago the shipping industry quite happily moved the shipping lane four miles to the east and the mortality went down dramatically,” he says. “Tags help us come up with reasonable solutions so whales and people can share the ocean amicably.”
Then came archival tags, surgically implanted inside the fish. A thin light sensor sticks out and gathers depth, temperature and light, sometimes for years. The light component allows daily calculation of approximate latitude and longitude. The part that sticks out also gives information on the reward, usually $500, that the fisherman who finds the tag is offered. One restriction is that to have any chance of retrieval, they must be placed on species that are likely to be caught by fishermen.
These tags fleshed out the primitive fish-travel notions yielded by the simple spaghetti tags and the short-term diving behavior provided by the acoustic tags. They revealed that in the seemingly featureless ocean, there are areas, dubbed “hot spots,” where multiple species gather, usually to feed.
The tags also strengthened beliefs that species are attracted to so-called “fronts,” border areas of waters of slightly differing temperatures. And they documented the success of the buoys known as Fish Aggregating Devices (FADs) placed in the open ocean by fishermen which, for no clear reason, attract great numbers of oceangoing fish.
The tags also yielded a startling discovery about blue-fin tuna. While it was known that tuna, once landed on a deck, had a warmer inner temperature than the water’s, it was not until internal tags recorded the fish’s temperature that they were revealed to be, like birds and mammals, warm-blooded creatures, which allows them to hunt in the very cold depths.
These tags were used with great success by Barbara Block of Stanford University. The tags showed that the adult specimens of Western Atlantic blue-fin tuna, one of the world’s most sought-after fish, spent considerable time in the eastern half. According to Gerry Scott, head of the science committee of the Madrid-based International Commission for the Conservation of Atlantic Tuna (ICCAT), which regulates the fishing of Atlantic tuna and other fishes, the eastern tuna population, which spawns (and mostly lives in) the Mediterranean, is seven to 10 times bigger than the western one, while the estimated catch, at 50,000 tons, is 25 times the Western catch of 2,000 tons.
Block points out that even though Western catches were halved 20 years ago, “There is still no sign of a recovery.” The data “suggests that the Eastern fishers are impacting Western recoveries, so they need to lower the quotas in the east,” she adds.
“The Europeans haven’t tagged nearly as many tuna, so we don’t know how many Eastern fish are being caught in the West,” Scott said. “But the European Union has started a tagging program and eventually tags will be able to show how many fish go to the other side.”
Jeff Polovina, a scientist at the National Oceanic and Atmospheric Administration (NOAA) in Hawai‘i who has tagged many loggerhead turtles, learned that they congregate in a so-called “hot spot” off Japan where long-line fishing has been going on for years. “They didn’t report their turtle by-catch, but now that we have a reason to believe they catch a lot of turtles, they can be approached and asked to set their lines deeper and use bigger hooks.”
The next generation of tags came in the late 1990s, developed by two main U.S. companies, Wildlife Computers and Microwave Telemetry.
While the archival tags opened up broad avenues of knowledge, they were restricted to species, like tuna, that were likely to be caught by fishermen who would turn in the tags for the reward.
A new generation called pop-up tags, which look like the wireless microphones pop stars use on stage, accumulate data for up to a year and at a programmed moment, detach themselves from the animal and float to the surface, where they download the data to passing satellites. They opened a new window into the habits of non-commercial species, since the data could be retrieved without catching the animal.
On great white sharks, they proved that these sharks were not coastal, as previously believed, but traveled long distances—from Australia to South Africa or across the Atlantic, for instance. “This was crucial in getting a ban on international trade in them,” said Pikitch of the Pew Institute.
Another surprise came from swordfish, which are harpooned as they bask on the surface. Pop-up tags showed that in fact, they “rarely see the light of day,” says Heidi Dewar, a researcher at the Inter American Tropical Tuna commission in La Jolla, Calif. “They spend most of the day feeding between 300 and 800 meters in very cold water and only come up at night, and they rarely bask during the day. They’re the only pelagic predator we know of that can stay that far down and forage without having to swim up to the surface to warm up.”
Ransom Myers, who runs a fish population dynamics lab at Dalhousie University in Halifax, Nova Scotia, says tags have proven invaluable. “To count fish, you have to know where they go,” he says. “For instance, now we know that great white sharks are wide-ranging. So from limited data that’s been taken in Canada, North Carolina and Virginia that show populations there are declining, we can now infer that the number of whites off Europe and Africa must be down too, even though we have very few data from there.”
But Keith Bigelow, a Hawai‘i-based fisheries scientist who does stock assessments of Pacific tunas and marlins for NOAA, disagrees. He says that while tags give you better understanding of population distribution and migration, they don’t help understand population dynamics. “To count fish, you need to know natural and fishing mortality, birth rate and age structure,” he says. “And electronic tags don’t give you any of that. We use simple dart [or spaghetti] tags, we tag 100,000 fish at a time every decade or so and the 20 percent we get back are sufficient to make assessments.”
the future
Kim Holland of the Coconut Island shark lab sees future tagging moving in two directions.
“We now know where fish go and when they go, but not why they go and what do they do there,” he says. “To know that, we need internal sensors that will tell us more about their feeding behavior and perhaps their blood chemistry. That would help us understand why they suddenly take deep dives or dash across an ocean.”
Roger Hill, the president of Wildlife Computers, a major manufacturer of archival, radio and pop-up tags, says there’s going to be a continuous improvement in the quality of the data and a trend toward further miniaturization with the goal of tagging smaller fish. The main barrier, he says, are the batteries. “There have only been minor improvements in lithium battery technology in over 10 years,” he says.
Phil Ekstrom, who designs archival tags for Lotek, a Canadian acoustic-tag maker, says he must wait for a mass market to generate the parts he needs. “Small tags with long lives need a tiny fuel cell running on dissolved oxygen and glucose. The big market driving that research is pacemakers,” he says.
The other direction electronic tags are heading in, says Holland, is getting tags to download their data without getting separated from the fish.
“Tagged tunas and whales and turtles passing within a kilometer of each other could exchange data and one could transmit everybody else’s data to a satellite or a research buoy,” he says. That would not only increase the data from each animal, but it would reveal which animals are present at the same time at “hot spots,” fronts, FAD buoys or near coastlines. “We still have no idea how marine animals interact,” he says. “For instance, we know schools of big tuna often swim under pods of dolphin, but we’re not sure why.”
A key component of that future is unfolding at the Canadian Foundation for Technological Innovation, where officials are expected to decide by the end of the year whether to fund a proposal to spend $32 million dollars to buy from the leading manufacturer of underwater receivers (who happens to be Canadian) some 4,000 receivers that would be placed in strategic spots and in “curtains,” one kilometer apart, around the world.
This new generation of receivers would be able to transmit their data to a boat passing overhead instead of having to be retrieved. It allows them to be placed much deeper than existing ones, up to 400 meters. At first, the receivers would only download basic information on the passing fish, such as its identity and its depth, says Ron O’Dor of Dalhousie University in Halifax.
But he says they could be modified to receive much heftier loads of data from passing archival tags by using underwater broadband transmission.
“Getting marine data through satellites is very expensive,” says O’Dor, the head of the Ocean Tracking Network, which is creating a global network of receivers. “The demand for cheaper data is growing and I think that will fund the research.”
He agrees with Holland that having tag-to-tag and tag-to-receiver transmission could quite likely be done in a decade, but what’s in doubt is just how detailed that data will be.
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Narra Lake for me. Just got to find a secluded spot somewhere where the weekend
hoards aren't hooning about.
The lake should be firing now that it's open again.
Those croc like lizards should be really on the chew now.
Cheers,
Pete.
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Not fish related but here is the story of the day in the papers:
Farts spark emergency landing
AN American Airlines flight has made an emergency landing after a passenger with severe gas problems struck matches to mask the odour of flatulence.
The flight from Washington to Texas landed at Nashville airport, in the southeastern state of Tennessee, after passengers alerted the crew to the smell of burning sulphur.
Lynne Lowrance, a spokeswoman for Nashville International Airport Authority said all 99 passengers and their luggage were taken off the plane and searched.
An unlucky canine team was also brought in to sniff the aircraft for explosives.
After intense questioning by the FBI, a woman passenger admitted to lighting matches on board the aircraft to conceal her gas, Ms Lowrance said.
“For a long time she did not admit to striking matches and I think that was just out of embarrassment,” she said.
“She did finally admit to it saying she had a medical problem about excessive gas.”
The unidentified woman was not charged, but “American did ban her from flying on their airline for a very long time,” Ms Lowrance said.
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Would the tides effect the lake much?
Saturday mornings tide doesn't look much good for out in Botany Bay I might head north for an early
No, the tidal effect inside the lake is minimal. it would only vary by about 30cm from high to low when it's open.
But it really does make a difference to the fishing.
Pete.
and a feed. 
One and all.
Snails Offer Hope For Pain Sufferers
in The Library
Posted
Snails offer hope for pain sufferers
The humble but lethal sea snail may hold the key to a better life for thousands of chronic pain sufferers.
Researchers from the University of Queensland believe conotoxins contained in potentially deadly sea snail venom could be used to create a treatment to replace conventional pain relief drugs such as morphine.
Dr Jenny Ekberg said her research had shown the conotoxin could produce pain relief without side effects in animals.
However, the conotoxin is yet to be tested on humans and Dr Ekberg said it could be several years before the treatment was able to be produced in marketable quantities.
"It's working beautifully at the moment, we just have to learn to synthesize it properly so that we can get enough amounts to start chemical trials on humans," she said.
Dr Ekberg said the lack of side effects meant the conotoxin had the potential to completely revolutionise pain treatment for cancer patients and chronic and neuropathic pain sufferers.
"Unlike other anaesthetics, it's very specific against the pain and doesn't cause any side effects - it's the first time anyone has discovered anything like this," she said.
Conventional medicines such as morphine can cause a range of unpleasant side effects, including nausea, vision and movement defects and drowsiness.
These symptoms often rendered sufferers unable to work and could lead to depression and, in some cases, suicide, Dr Ekberg said.
"I've met people with this, it's really horrible ... neuropathic pain, which is caused by damaged nerves, not tissue, you have to live with forever," she said.
If the research proves successful Dr Ekberg hopes the treatment will allow sufferers to live normal lives and continue working.
She believed the treatment would initially be administered through hospitals but hoped patients would eventually be able to inject it themselves at home.