“Small fish may have small brains but they still have some surprising cognitive abilities”, says Dr Jeremy Kendal* from Durham University’s Anthropology Department.

Dr Kendal is the lead author of a new study showing that Nine-spined stickleback fish (Pungitius pungitius) can compare the behaviour of other sticklebacks with their own experience and make choices that lead to better food supplies.

“‘Hill-climbing’ strategies are widely seen in human society whereby advances in technology are down to people choosing the best technique through social learning and improving on it, resulting in cumulative culture”, says Dr Kendal. “But our results suggest brain size isn’t everything when it comes to the capacity for social learning.”

Around 270 Nine-spined sticklebacks were caught from Melton Brook in Leicester using dip nets. After being divided into three experimental groups and one control group, the fish were housed in different aquariums and the fish in the experimental groups were subjected to two different learning experiences and two preference tests in a tank with a feeder placed at each end.

1.) The fish were free to investigate both feeders during a number of training trials. One feeder (dubbed “rich feeder”) always handed out more worms than the other one (dubbed “poor feeder”). The fish were then tested to see which feeder they preferred.
2.) In the second training trail, those fish that come to prefer the rich feeder could see other fish feeding. During this stage, the rich and poor feeders were swapped around and the rich feeder either gave even more worms than before or roughly the same or less. During the second test, the fish were once again free to explore the tank and both feeders. Around 75 per cent of the Nine-spined sticklebacks had learned from watching the other fish that the rich feeder, previously experienced first hand themselves as the poor feeder, gave them more worms. In comparison, significantly fewer sticklebacks favoured the feeder that appeared to be rich from watching other sticklebacks if they themselves had experience that the alternative feeder would hand out roughly the same or more worms.

Further testing showed that the sticklebacks were more likely to copy the behaviour of fast feeding fish.

“Lots of animals observe more experienced peers and that way gain foraging skills, develop
food preferences, and learn how to evade predators”, Dr Kendal explained. “But it is not always a recipe for success to simply copy someone. Animals are often better off being selective about when and who they copy. These fish are obviously not at all closely related to humans, yet they have this human ability to only copy when the pay off is better than their own.”

The study, which has been published in the journal Behavioral Ecology, was carried out by scientists from St Andrews and Durham universities and funded by the Biotechnology and Biological Sciences Research Council. The lead author of the study, Dr Kendal, is a Research Council UK Fellow.

Since the early days of the 20^th century, marine biologists have pondered one of the world’s most puzzling questions – if a tree falls in the ocean, can the cephalopods hear it?

Fish use their swim bladder to hear, but cephalopods – a group of marine invertebrates that includes octopus, squid, cuttlefish and nautiluses – do not have any gas-filled chamber to use for this purpose and this has lead some scientists to suggest that these creatures are incapable of detecting the pressure wave component of sound.

A team led by sensory physiologist Hong Young Yan of the Taiwan National Academy of Science in Taipei has now, for the first time in history, been able to show that cephalopods can hear sounds underwater using their statocysts.

A statocyst is sac-like structure containing sensitive hairs and a mineralised mass. Fish can use their statocysts to detect sounds, so Yan suspected that other underwater creatures might do the same. After successfully showing that prawns use their statocysts to detect sounds underwater, Yan extended his experimentation from to prawns to cephalopods.

A quandary when researching cephalopods is their delicate bodies. When researchers wish to determine if an organism is capable of hearing or not, they normally attach electrodes to exposed nerves and measure how the nervous system electrically responds to sound. This type of invasive procedure can however easily injure a cephalopods and Yan was therefore forced to come up with a better method. Instead of attaching electrodes to exposed nerves, Yan placed the electrodes on the cephalopods’ body and measured the electrical activity in the brain. Thanks to this method, Yan could show that cephalopods do have a sense of hearing.

The lack of any gas-filled chamber means that cephalopods can’t amplify sounds the way a fish can, but their hearing is probably as good at that of prawns and similar invertebrates.

Yan now wish that his discovery will be used to further the understanding of cephalopod behaviour.

“The key question which I would like to investigate is what kind of sounds are they listening to?” says Yan. “Perhaps they listen to sound to evade predators and can eavesdrop to sounds made by their prey. […]Squid are heavily preyed upon by toothed whales including

dolphins. So perhaps their hearing would aid them to avoid the pinging sounds made by

dolphins. […] Or, perhaps they even could make sounds to communicate among themselves. “

During recent years, massive jellyfish congregations have appeared along the Northeast U.S. coast, in the Gulf of Mexico, in the Mediterranean, in the Black and Caspian Seas, and in South-East Asian coastal waters.

“Dense jellyfish aggregations can be a natural feature of healthy ocean ecosystems, says Dr Anthony Richardson of the University of Queensland, but a clear picture is now emerging of more severe and frequent jellyfish outbreaks worldwide.”

A new study by Richardson and his colleagues at the University of Miami, Swansea University and the University of the Western Cape, presents convincing evidence that these massive jellyfish populations are supported by the release of excess nutrients from fertilisers and sewage, and that fish populations depleted by over-fishing no longer are capable of keeping them in check.

“Fish normally keep jellyfish in check through competition and predation but overfishing can destroy that balance,” Dr Richardson says. “For example, off Namibia intense fishing has decimated sardine stocks and jellyfish have replaced them as the dominant species. Mounting evidence suggests that open-ocean ecosystems can flip from being dominated by fish, to being dominated by jellyfish. This would have lasting ecological, economic and social consequences.”

In addition to this, the distribution of many jellyfish species may extend as a response to global warming and an increased water temperature could also favour certain species by augmenting the availability of flagellates in surface waters.

The study, which was lead by CSIRO Climate Adaptation Flagship, has been published in the journal Trends in Ecology and Evolution.

You can find more information about CSIRO Climate Adaptation Flagship here:

450 pound blobs filling up the Sea of Japan

The changing ecosystems affect a long row of different jellyfish species, but some of the most spectacular jellyfish congregations observed during recent years have involved the Nomura jellyfish (Nemopilema nomurai) living in the Sea of Japan (Also known as the East Sea). This colossal species, which can reach a size of 2 metres* across and weigh up to 220 kg**, is also present in the Yellow Sea as well as in the rest of the East China Sea.

After becoming a major problem in the region, the Nomura jellyfish population is now combated by a special committee formed by the Japanese government. Killing jellyfish or ensnaring them in nets will however only prompt these animals to release billions of sperm or eggs; aggrevating the problem rather than reducing it. Coastal communities in Japan have started to harvest jellyfish and sell them as a dried and salted snack, and students in Obama, Fukui have started making jellyfish cookies and jellyfish-based tofu.

* circa 6 feet 7 inches

** circa 450 pounds

Indonesia is getting ready to sink foreign boats carrying out illegal fishing in Indonesian waters.

“We are glad the House`s Commission IV supports us in this,” Marine Resources and Fisheries Minister Freddy Numbery said at a meeting with the House commission this week.

Numbery says firm action is needed to deter foreign boats from continuing to poach, and that his office and the parliament were currently revising the law on marine resources with regard to dealing with crimes in the seas.

Elviana, a member of Commission IV, agreed with the minister and said that firm actions needed to be implemented immediately to deter foreign parties intending to steal fish from Indonesian waters.

“Tuna fish sells well so that many foreign fishermen are venturing into the country’s waters“, she said. “This must not be allowed to continue.”

Earlier, Indonesian authorities have seized illegal fishing boats and auctioned them out, but this system seems to have been ineffective.

“It is believed auctions have been arranged to ensure that the boats can be sold to their owners who are also the suspects,” Elviana said, adding that illegal boats such as from Thailand still continued operating in a great number.

Nova Scotia is not the only place with odd looking lobsters; the original Scotland also has some strange colour morphs dwelling in its waters.

If you visit the rock pool at Deep Sea World in North Queensferry, you can for instance encounter one electric blue lobster with white markings and one pitch-black lobster adorned with vivid orange colours that contrast beautifully against the dark areas. Picture here

The blue lobster was caught a quarter of a mile off the coast of Fife on the Scottish east-coast last year by Buckhaven fisherman Keith McKay, 47.

McKay said he had occasionally seen dark blue lobsters since he started laying creels with his father as an 11-year-old boy.

But he added: “I’ve never seen anything like this one in my life. I was surprised at how pale a blue it was. It was really brightly-coloured. I would call it electric blue. I was so surprised I pulled up alongside another fishing boat to show them what I had caught.”

Strangely coloured lobsters are the result of them being genetically different from other lobsters. In the wild, not having the normal olive-grey, mottled camouflage pattern is a disadvantage since predators can spot gaudy lobsters easily against the ocean floor, but for the lobsters living at Deep Sea World, the “genetic defect” actually turned out to be an asset since their flamboyant colours is what saved them from ending up on a dinner plate.

A number of Japanese citizens living in the Ishikawa Prefecture have made some strange observations during the last few days.

Nanao, Japan, June 4

During the evening of June 4, a man suddenly heard a plopping sound in a parking lot of the Nakajima citizens centre in Nanao. When he looked back, he was surprised to see tadpoles scattered over a car and on the ground. According to Kiwamu Funakura, 36, an official at the centre who went to the parking lot at the time, about 100 tadpoles, each 2 or 3 centimetres long, were scattered over an area measuring about 200 square meters.

Hakusan, Japan, June 6

Two days later and roughly 70 kilometres southwest of Nanao, a similar event occurred in another parking lot. In the morning of June 6, between 20 and 30 dead tadpoles were found on a car windshield and other places in a Hakusan parking lot, with some reportedly having lost their original shape.

Nanao, Japan, June 8

Back in Nano, Takeshi Kakiuchi, 62, a member of the Nanao Municipal Assembly, found six tadpoles on his car and on the ground around his home Monday morning. Kakiuchi’s home is located roughly 4 km from the Nakajima citizens centre.

Nakanotomachi, Japan, June 9

On Tuesday evening, Yukio Oumi, 78, found 13 fish on the back of his truck and on the ground around his home in Nakanotomachi. The fish are believed to be crucian carps, each measuring about 3 centimetres.

Fish and frogs falling from the sky?

The reason behind the strange events has not yet been determined, and the Kanazawa Local Meteorological Observatory says it has no information that any tornadoes occurred on the days when the animals appeared.

Susumu Aiba, professor at the Kanazawa Institute of Technology, says that small-scale wind gusts may have swept over limited areas, swirling up water and any creatures living in it. If the gusts were small enough, they may have been able to avoid meteorological detection.

Another suggestion comes from Kimimasa Tokikuni, the head of the Ishikawa prefectural branch of the Japanese Society for Preservation of Birds. “Birds such as herons or umineko that had these tadpoles in their mouths or gorges might have dropped them because they were startled by something while flying,” he says. All the places where animals seem to have fallen from the sky during the last few days are located in close vicinity to flooded rice paddies, so birds may have caught tadpoles and small fish there in an attempt to feed their young. Herons and other water fowl are in the middle of their breeding period right now.

We often think of evolution as something extremely slow that takes place over the course of thousands or even millions of years. The truth is however that certain adaptations can occur very quickly, sometimes over the course of just a few generations.

Male Guppy. Copyright www.jjphoto.dk

Eight years later, a time period equivalent of less than 30 guppy generations, the guppies living in the low-predation environment had adapted to this environment by producing larger and fewer offspring with each reproductive cycle.

“High-predation females invest more resources into current reproduction because a high rate of mortality,
driven by predators, means these females may not get another chance to reproduce,” explained Gordon, who works in the lab of David Reznick, a professor of biology.

The guppies living below the barrier waterfall where there were a lot of predators did not show any signs of producing fewer or larger offspring.

“Low-predation females, on the other hand, produce larger embryos because the larger babies are more competitive in the resource-limited environments typical of low-predation sites”, Gordon said. “Moreover, low-predation females produce fewer embryos not only because they have larger embryos but also because they invest fewer resources in current reproduction.”

The paper will be published in the July issue of The American Naturalist.

Swanne Gordon’s research team included David Reznick and Michael Bryant of UCR; Michael Kinnison and Dylan Weese of the University of Maine, Orono; Katja Räsänen of the Swiss Federal Institute of Technology, Zurich, and the Swiss Federal Institute of Aquatic Science and Technology, Dübendorf; and Nathan Miller and Andrew Hendry of McGill University, Canada.

Financial support for the study was provided by the National Science Foundation, the Natural
and Engineering Research Council of Canada, the Le Fonds Québécois de la Recherche sur la Nature
et les Technologies, the Swedish Research Council, the Maine Agricultural and Forestry Experiment
Station, and McGill University.

U.S. researchers John F. Switzer* and Robert M. Wood** have described a new species of darter from the Meramec River drainage of Missouri, USA. The new species has been named Etheostoma erythrozonum and is the first known fish species endemic to the Meramec River drainage. Its common name is Meramec Saddled Darter.

Etheostoma erythrozonum is a sister species of the Missouri Saddled Darter, Etheostoma tetrazonum, an inhabitant of the Gasconade River, Osage River, and Moreau River drainages. The Missouri Saddled Darter is one of several darter species endemic to the northern Ozark region of Missouri. When E. tetrazonum was first described, it was only known to exist in the

Osage and Gasconade River systems. However, within a year of its description, individuals of E. tetrazonum were identified from the Meramec River system, a tributary of the Mississippi River. Since then the distribution of E. tetrazonum has been considered to include the Meramec, Gasconade, Osage, and MoreauRiver systems.

In 1984, the first sign of E. tetrazonum actually being more than one species was found when an electrophoretic analysis unveiled considerable genetic divergence between populations of E. tetrazonum from the Meramec and Osage River drainages. This notion has now been supported by a recent molecular phylogenetic analysis of 13 populations of E. tetrazonum,

As a result, the specimens living in the Meramec River drainage have now been recognized as a separate species and the name E. tetrazonum will from now on only pertain to the specimens native to the Moreau, Osage, and Gasconade River drainages. As mentioned above, the Meramec River drainage species has been given the name Etheostoma erythrozonum.

E. erythrozonum is very similar to E. tetrazonum but without the prominent blue-green colouration. Some male E. erythrozonum darters do have a blue spinous dorsal fin base, but the blue colour is inconspicuous and never as outstanding as in E. tetrazon. (The anal fin of E. erythrozonum is also blue-green.)

Male E. erythrozonum darters sport a horizontal red-orange stripe that runs along the lower sides of the body from the pelvic fins to the anal fin with an irregular dorsal margin, while the male E. tetrazonum darter has a dorsal stripe with a well-defined dorsal margin in. Another notable difference between the two species is how E. erythrozonum has a series of irregularly shaped red-orange blotches instead of the well defined vertical bars seen on male E. tetrazonum darters.

The paper has been published here in the journal Zootaxa. Picture is Available in the online publication.

* John F. Switzer, U.S. Geological Survey, Leetown Science Center, Aquatic Ecology Branch, Kearneysville, West Virginia

E-mail: jswitzer@usgs.gov

** Robert M. Wood, Department of Biology, Saint Louis University, St. Louis, Missouri

E-mail: wood2@slu.edu

Brachypopomus gauderio is not the only electric knifefish recently described from South America, U.S. researchers John P. Sullivan* and Carl D. Hopkins** have described another member of the genus Brachyhypopomus and given it the name Brachyhypopomus bullocki.

This new species is named in honour of Theodore Holmes Bullock, a renowned neurobiologist who died in 2005. Bullock was a pioneer of the comparative neurobiology of both invertebrates and vertebrates and is credited with the first physiological recordings from an electroreceptor and for championing electric fishes as a model system in neurobiology. The electric organ discharge waveform of Brachyhypopomus bullocki is biphasic, 0.9–1.6 milliseconds in duration, and the pulse rate varies from 20–80 Hz.

Brachyhypopomus bullocki is found throughout the Orinoco Basin in Venezuela and
Colombia. It can also be encountered in the in the Rio Branco drainage of Guyana and the Roraima State of Brazil, as well as in the upper part of Rio Negro near the mouth of Rio Branco.

Brachyhypopomus bullocki appears to prefer clear, shallow, standing water in open savannah, or savannah mixed with stands of Mauritia palm. It has also been collected among plants growing along the banks of small pools fed by streams. In Rio Negro, a specimen was found amongst palm leaf litter near the outlet of a black water stream.

Brachyhypopomus bullocki distinguishes itself from its close relatives by having larger eyes (comparative to the head), a short abdomen, and distally enlarged poorly ossified third and fourth branchiostegal rays.

The paper can be downloaded from Cornell University.

* John P. Sullivan, Department of Ichthyology, The Academy of Natural Sciences, Philadelphia. Email: sullivan@ansp.org

** Carl D. Hopkins, Department of Neurobiology and Behavior, Cornell University, New York. Email: cdh8@cornell.edu

Brazilian ichthyologists Julia Giora and Luiz Malabarba have described a new species of electric knifefish and named it Brachypopomus gauderio.

The fish lives in the central, southern and coastal regions of the Rio Grande do Sul state in Brazil, as well as in Uruguay and Paraguay, and its name is derived from the word “gaúcho”, a local term denoting a person living in the countryside (pampas) of the Rio Grande do Sul state, southern Brazil, Uruguay and Argentina.

Brachypopomus gauderio inhabits river banks, slow-moving creeks, lagoons, and flooded areas with muddy or sandy bottoms and has only been found among surfacing or floating plants.

You can distinguish Brachypopomus gauderio from its close relatives by its yellow dorsal surface, and on the brown markings which form a reticulate pattern.

I have not been able to find a picture.

The description has been published in the journal Zootaxa.

”Giora, J and LR Malabarba (2009) Brachyhypopomus gauderio, new species, a new example of underestimated species diversity of electric fishes in the southern South America (Gymnotiformes: Hypopomidae). Zootaxa 2093, pp. 60–68.”