According to Christian Agrillo, an experimental psychologist at the University of Padua in Italy, the North American mosquito fish can count up to four. This rudimentary mathematical ability makes it possible for the North American mosquito fish to count how many other fish that are nearby – but only up to four. Similar counting abilities have already been observed in dolphins, but until now researchers only new that fish could tell big shoals from small ones, not that they were able to actually count.

In earlier research, Agrillo and his colleagues found that a female specimen of the North American mosquito fish will swim to the largest nearby shoal to protect herself from a harassing male. In order to do so, she must of course be able to somehow tell the difference between a larger shoal and a smaller one.

To establish exactly how advanced the counting ability of the North American mosquito fish was, Agrillo et al continued their research by testing if a lone specimen would prefer to join a shoal consisting of 2, 3 or 4 other fish. The study showed that female fish could tell the difference between two shoals even when the shoal size differed by only one specimen. Females would significantly more often prefer to join a shoal consisting of four others rather than three, and would also favour shoals comprised of three fish rather than of two.

When a new series of experiments were conducted using even larger shoals, researchers found that the female North American mosquito fish were unable to directly count over four. If two shoals differed in size by a ratio of 2:1 she would go for the larger one, but if the difference was smaller she seemed to conclude that they were “both big”. She would for instance not favour a shoal consisting of 12 fish over a shoal of 8, but could clearly tell a shoal of 16 from a shoal of 8. The female North American mosquito fish therefore seems to have the ability to estimate larger numbers, but not very exactly.

The results of the study can be found on BBC’s site Loveearth.com

I usually don’t like to write about rumours and speculations but sometimes they are interesting enough to warrant a few rows here in the news section. There is a growing speculation and fear among tuna fisherman that tuna fishing will be strictly regulated or banned before the end of the year.

The speculations state that a complete ban on Tune fishing in the entire Atlantic Ocean will be announced in November during the International Commission for the Conservation of Atlantic Tuna meeting in Morocco. This would be a result of plummeting tuna populations and increased pressure from environmental organisations. American fishermen are believed to be among those supporting a complete ban which might be true as the US have a very small tuna fishing industry. The only exception from the ban would be sport fishing.

There is also a rumour that the tuna fishing ban won’t be limited to the Atlantic but that a global tuna fishing ban might be close to being announced. It is unclear whether the ban would include all tuna species or only the blue fin tuna but the later seems more likely.

Personally I find the announcement of a global or even an Atlantic tuna fishing ban very doubtful even if I would appreciate the imitative. (Despite the fact that I love grilled tuna) A tuna fishing ban in the Mediterranean seems more likely but might also meet more resistance due to large fishing operations present there. It is also doubtful if such a ban would be respected in the Mediterranean as the fishermen there have a history of breaking the rules such as in this incident I reported about earlier this year.

What do you guys think? Will we see a Tuna ban before the end of the year? Is one needed?

A lot of fish have died following poor event planning before the Cairns triathlon. The organiser strung jellyfish nets across the Marlin Marina in cairns as a part of the event planning for the triathlon Authorities decided to leave the nets in during the night but forgot about the tide. Large schools of fish were caught in the net and when the tide rolled out the fish ended up above water and died. The nets were placed to prevent swimmers from being stung by jellyfish.

Event organisers and the Department of Fisheries and Primary Industries last night defended the event planning and use of the nets and said it was an “unusual” accident. The net was approved by DPIF and marine parks is of the same type the use around beaches to protect beach goers against jellyfish. DPIF is going to investigate the accident.

Officials also defended not taking down the nets immediately after the fish kill was discovered.

One of the involved believes the fish were chased into the net by a predator.

Paul Johnston, a local boat owner was shocked by the scene. He seem to have less faith in the event planners and says that “There will be another low tide and it’s all going to happen again”

Video from the accident

New research have shown that fish are much smarter than scientist previously thought and many fish species as just as intelligent as rats.

Dr Mike Webster of St Andrews University have researched the intelligence in fish and his research shows that fish shows clear signs of intelligence when they are in danger. He says that:
“It is probably accurate to say that many fishes such as minnows, sticklebacks and guppies are capable of the same intellectual feats as rats or mice.

Goldfish don’t have goldfish memories

His experiments have shown how fish use techniques learned through shared learning to avoid predators. He discovered that a fish that is separated from the shoal by a clear plastic divider will make its own decisions on how to avoid predators while a fish that is kept with other fish will decide on how to act by watching the rest of the fish and the choices they make.

Dr Mike Webster claims that “These experiments provide clear evidence that minnows increasingly rely on social learning as the basis for their foraging decisions as the perceived threat of a predator increases.”

He further claims that this dispels the old myths of goldfish memory and that fish have notoriously poor memories.

I am sure the fact that fish are smarter than they are given credit for doesn’t come as a surprise for any aquarist, especially not to aquarists that have kept South or Central American cichlids like jags and Oscars. Species that are know to depress if they get under stimulated and that sometimes (some specimens) don’t eat if the owner is away.

Regular salmon

Biologists keeping track of the sockeye salmon populations in central Idaho (Sawtooth Mountains) have good news to report. More sockeye than in any other year in the last two decades have made their way pass the eight dams on the Columbia and Snake rivers and returned to idaho. 507 fish have been counted so far. That might not sound much but considering that the number has been in the single digits each of the last five years and that only 16 wild sockeye returned between 1991 and 1998 it is a large improvement. It might however be too early to start celebrating as 257 sockeye returned in 2000 followed by a number of bad years.

The improvement is believed to be due to the fact that 180,000 smolts were released in Idaho lakes in 2006. Some of the returning fish are likely artificially spawned at the Eagle Fish Hatchery in Southwestern Idaho as part of a program to help boost the sockeye populations around the Sawtooth Mountains.

The 507 returning fish might be a better number than in many years but it is still no where near the historical levels of Sockeye salmon that once wandered the 900 miles from the Pacific Ocean to Idaho lakes like Redfish, Pettit and Alturas. As many as 35,000 sockeye used to return each year. The population decline is believed to be primarily due to four dams along the lower Snake River in Eastern Washington.

This is a short post as I think everyone should see these pictures of migrating golden rays. Not all golden rays migrate but there is one population in the Mexican gulf that each year migrate, clockwise from western Florida to the Yucatan. They migrate in large schools, often up to 10 000 fish strong and color the sea where they swim. Each ray grow to be 7ft (2.1 meters) wide from fin tip to win tip.

Enough talk. Visit this site to see the great pictures

For many aquarists, the joy of keeping an aquarium is not only about watching colourful fish dart around in the living room, it is also a way of learning more about the delicate web we call an ecosystem and how dead matter and living organisms interact with each other to create an environment where life can not only exist but flourish. It therefore comes as no surprise that you can find a lot of environmentally conscious aquarists, and that many of today’s expert biologists and wildlife authorities were steered into the path of environmental science at a very young age while striving to keep the inhabitants of their fish tank alive. Keeping an aquarium can unfortunately be a problematic hobby for the environmentally conscious, but don’t loose heart – there are loads of things that you can do to make your aquarium less of a burden for mother earth. As a matter of fact, many aquarists have actually helped in preservation work, e.g. by keeping and breeding endangered fish from severely damaged habitats, thus preventing species from becoming completely eradicated.

1.) Pick species that appreciate the same temperature as you do

Keeping an aquarium heated can require loads of energy and dig a large hole in your pocketbook. Many aquarists automatically chose tropical species in need of a temperature in the 75-82ºF (24-28ºC) range, despite the fact that they keep their homes heated up to 70°F (21°C) or so. By choosing subtropical species that prefer roughly the same temperature as you do you can save considerably amounts of energy in the long run. It can however still be a good idea to keep a heater with a thermostat in the aquarium as a precaution against sudden drops in temperature. The smaller your aquarium, the more rapidly it will loose heat if the surrounding temperature drops. Choose a supplier that sells green electricity.

2.) Never release fish or other creatures into the wild

If you for any reason cannot care for your aquarium inhabitants anymore, you need to find them a new keeper or euthanize them. It might be tempting to release them into the wild, but this is a big no-no. Releasing living organisms into environments where they don’t belong can wreck havoc with existing ecosystems and must therefore be avoided. Even if you keep species that occur naturally in your local environment you shouldn’t release them back into the wild because they may have come in contact with non-native bacteria, viruses, parasites etcetera in the aquarium that could cause problems for wild flora and fauna.

Fish are so called cold blooded animals and it is therefore easy to euthanize them by decreasing the water temperature. If you need to euthanize a fish or other cold blooded aquarium creature, simply place it in a water filled container and put the container in the freezer. As the water temperature gradually decreases, the metabolism of the animal will slow down and it will fall into a comatose like state before dying.

3.) Purchase locally bred or caught fish

Instead of purchasing fish that have to be flown in from the other side of the planet, you can search for fish that are being bred or caught in your area, country or (at least) part of the world. As a bonus for you, locally bred fish are often better acclimatized to the tap water in your area and more prone to breed in captivity.

4.) Turn your back on unsuitable harvesting methods

Unfortunately, devastating harvesting methods like dynamite fishing are still fairly common within the aquarium trade. Always make an effort to find out which technique that has been used to catch the fish you’re interested in purchasing. It can be hard to find unbiased information, but it is still worth trying. Paying a little extra for fish that has not been caught with dynamite and similar can also be a very sound investment since unsuitable harvesting methods tend to cause a lot of damage to the fish and decrease its chances of survival in captivity.

5.) Participate in breeding programs

By participating in a breeding program you can help supply the aquarium market with captive bred fish and ease the strain on wild populations. You can naturally do this on your own as well, but joining a breeding program is a great way of getting information on how to breed high quality fish and avoid common pitfalls. You may also be able to purchase or borrow hard to find species to use in your breeding efforts, especially if you have had success in breeding similar species in the past.

6.) Keep the fish alive

This last point might seem like a no-brainer, but many beginner aquarists are coaxed by fish shops into thinking that four months is a perfectly normal lifespan for all sorts of aquarium fish and that you should expect to constantly purchase new fish to keep your tank populated. It is true that some species have a natural life span of less than six months, but the overwhelming majority of known fish species live much longer than this and there are actually quite a few species that will live for 10 years or more in a well kept aquarium. If all your fish goes belly up after just a few months in your tank, you’re probably doing something wrong. If aquarists all over the world would become better at actually keeping their fish alive, less energy would have to be devoted to transporting replacement fish, and it would also alleviate the strain on wild populations of desirable aquarium fish.

So, how can we increase our chances of keeping healthy and long-lived fish in our tanks? First and foremost, always read up on each species you wish to keep before you make a purchase. By learning about a species preferred environment, temperature, water chemistry, diet, tank mates, and so on, you will be more apt at keeping it alive throughout its natural life span. Do not mix species with different preferences in water chemistry, temperature and similar. You might very well be able to keep them alive, but they will not thrive and they will be more prone to health problems which increase the risk of an untimely death.

It is also important to read up on aquarium management techniques and always strive to increase ones knowledge on general aquarium maintenance. Do not hesitate to ask more experienced aquarists for advice. Today, the Internet has made it easy to keep in touch with aquarists from all over the world through aquarium forums and e-mail. If you’re lucky, there will also be a local aquarium club in your area.

The June sucker, Chasmistes liorus, is a critically endangered fish endemic to Utah Lake and the Provo River. The fish was once plentiful within its range but is now facing problems with pollution, turbidity, drought, alteration of water flow, loss of native vegetation, and the introduction of new species, primarily the European carp (Cyprinus carpio) and the walley (Sander vitreus vitreus).

Grass Carp

The European carp was introduced to the lake as a food fish during the late 19^th century and is causing severe problems for the June sucker by ripping out weeds while feeding along the bottom. Without these weeds, June sucker fry have no place to hide and end up in the stomach of predatory fish like walley and bass.

During recent years, about 100,000 June suckers have been raised in a hatchery and released into the lake, but the state of Utah are now saying that they have to do something about the carp problem if they want the June sucker population to survive in the long run. “It’s probably the biggest barrier to June sucker recovery,” says Mike Mills, the local coordinator for the recovery program.

Wildlife officials are now planning on removing roughly 1 million pounds of European carp from the lake each year during the next coming six years in an effort to make the environment more favourable for the June sucker. But what do you do with 6 million dead carps?

As of now, a substantial amount of dead carps has been turned into compost, and there is also talk about using them for international humanitarian missions. Other suggestions include converting them into bio-fuels and garden fertilizer, or use them as a protein source in imitation crab meat for the food markets of Central Europe and Asia. The old fashion solution of turning fish into fish sticks, canned fish, fish sauce, fish meal and pet food is naturally also an option.

Some have suggested that the carps should be tossed out to rot away in a landfill or placed in a hole in the desert, but Wildlife officials are not very keen on that idea. “It’s hard to see a fish wasted when there are people in the world that are starving and could use the food,” says Mike Mills. “It’d be great if we could find a market for these fish and that market could fund the whole effort.“

Source: msnbc.msn.com

I thought I would write a few words about some of the many good fish cams that are available on the net even though they sometime can be hard to find among all the bad ones.

I would like to start by mentioning the Amazon River cam that is provided by the Smithsonian national zoological park. This cam allows you to follow the action in a Amazon river basin aquarium containing turtles, piranhas, arapaima and red tailed catfish. You can view this camera here . The Smithsonian national zoological park website also offers a webcam where you can see cats fish as well as a number of other good animal web cams.

The Oregon Museum of Science and Industry features a salmon can where you can see young salmon that is growing up in aquarium. You can watch this cam in your browser or in your media player. On the negative side can be said that it can be hard to see any fish on this feed.

Myfishcam.com offers a koi fish webcam that can be interesting to watch. Click here to watch. Sometimes this feed only work in Media player and not in the browser.

Biotactic Fish & Wildlife features a web came that show the life in Grand River, Ontario, Canada. During the days this cam provides color pictures and during the night it provide infrared imagery. Recent sightings in this cam includes rockbass spawning, crayfish mating, predation. Visit the camera now.

You might also want to step by the fish-school.com cam. Here you can se them training their goldfish comet using the training methods they have developed and teaching others to use. The feed is empty between training sessions but there are archived clips that you can see if there is nothing going on in the live feed. You can see that camera, here

A Couple of Other Aquarium website i stumbled on while looking for these:

Fish Med: Everything you should know to cure and prevent aquarium fish disease

Two fish species, one frog species and a number of bat flies – all previously unknown to science – are believed to have been found in Guyana during the filming of a British TV series.

While working on the three-part series “Lost Land of the Jaguar” for BBC One, a team of researchers and wildlife film-makers spent six weeks exploring the rainforests of Guyana. “In a short time, we caught hundreds of species, 10% of which may be new to science. It was unreal, unbelievable,” says zoologist Dr George McGavin, one of four presenters of the documentary.

The two newfound fishes are both small creatures; one is a small banded fish belonging to the genus Hemiodus and one is a tiny parasitic “vampire” catfish that fell out of the gills of a bigger catfish. The gill dwelling fish is a member of the genus Vandellia and hence a close relative of the feared Candirú catfishes, famous for their peculiar capability of entering the human urethra. They are commonly referred to as “vampire fish” since they feed on the blood of other animals.

The scientists partaking in the expedition will now have to sit down and research all their findings more thoroughly in order find out if this is actually entirely new species, and if so, describe them scientifically and assign them scientific names. As Dr McGavin says “Catching is the easy bit, the hard bit is going back to the lab and examining the species, comparing them to collections and books – seeing if they are new to science. One hour in the field can equal hundreds of hours in the lab.”

In addition to the possibly newfound species, the documentary includes highlights like footage of the world’s heaviest snake, the Anaconda, the world’s bulkiest eagle, the American Harpy Eagle (Harpia harpyja), and the enormous Goliath spider (Theraphosa blondi) – also known as the Goliath birdeater. The film-makers have also managed to capture on film the elusive Jaguar from which the series derives its name.

BBC aired all three episodes of “Lost Land of the Jaguar” in August 2008.

You can see a film of the small banded fish here

Guyana, previously known as British Guyana, is a small nation located at the Atlantic side of southern South America. It borders to Suriname, Brazil, and Venezuela. Being slightly smaller than the state of Idaho, Guyana is the third smallest country on the South American mainland. The land can be divided into four main natural regions: a narrow strip of fertile plain along the Atlantic coast where most of the population lives, a hilly white sand belt more inland, a highland region covered in dense rainforest across the middle of the country, and a grassy savannah habitat that can be found to the south as well as in the interior highlands.

Source: news.bbc.co.uk