The Bonefish is an extremely popular fishing that lures 1000s of sport fishermen to try their luck each year but until now it has been unknown how this species reproduce. Andy Danylchuk, a researcher working at University of Massachusetts Amherst and his colleagues have been studying bonefish for the last few years using using ultrasonic transmitters to tag and track the fishes movements. The research have been conducted outside Bahamas. The results can now be found in the online version of the journal Marine Biology.

The research show that bonefish gather by the thousands at pre-spawning aggregation sites for a few days each month during the spawning season (October to May). This usually take place during the full and new moon. The fish than migrate together out into deeper water at dusk where they than spawn at depths of more than 1000 ft (300m).

Andy Danylchuk says that “One possible benefit of bonefish migrating to offshore locations to spawn is that it increases the dispersal of their fertilized eggs, especially with the high tides that happen with the new and full moons.”

He also says that this is “This is the first time movement patterns of bonefish to deep water have been formally described,” and that “This new understanding of bonefish movement and spawning aggregations has significant implications for their conservation,”

The researcher have tagged and followed a total of 60 fish over two years.

Hammerhead shark by Suneko

Using satellite tag technology, research assistant professor Neil Hammerschlag and his colleagues have tracked a hammerhead shark during 62 days, as it journeyed from the southern coast of Florida to the middle of the Atlantic off the coast of New Jersey.

The straight line point-to-point distance turned out to be 1 200 kilometers (745 miles).

“This animal made an extraordinary large movement in a short amount of time,” says Hammerschlag, director of the R.J. Dunlap Marine Conservation Program at the University of Miami Rosenstiel School of Marine & Atmospheric Science. “This single observation is a starting point, it shows we need to expand our efforts to learn more about them.”

The hammerhead is believed to have been following prey fish off the continental slope, and it was probably prey that caused it to enter the Gulf Stream current and open-ocean waters of the northwestern Atlantic.
The study headed by Hammerschlag is a part of a larger effort to satellite track tropical sharks to find out if any areas are especially important for their hunting, mating and rearing of young. Hammerschlag also wish to document their migration routes.

“This study provides evidence that great hammerheads can migrate into international waters, where these sharks are vulnerable to illegal fishing,” says Hammerschlag. “By knowing the areas where they are vulnerable to exploitation we can help generate information useful for conservation and management of this species.”

More information can be found in the paper “Range extension of the Endangered great hammerhead shark Sphyrna mokarran in the Northwest Atlantic: preliminary data and significance for conservation“, published in the current issue of Endangered Species Research. The paper’s co-authors include Hammerschlag, Austin J. Gallagher and Dominique M. Lazarre of the University of Miami and Curt Slonim of Curt-A-Sea Fishing Charters.

The annual whale expedition off the Japanese port city of Kushiro ended this weekend after having caught 59 minke whales, the Japanese Fisheries Agency said in a statement.

The whales where caught as a part of a research program that whaling opponents claim is just a cover for commercial whaling. A maximum capture of 60 whales is allowed under this research program, which is authorised by the International Whaling Commission (IWC).

The Fisheries Agency says the goal of the hunt was to study the feeding patterns of the whales and their effect on fish stocks. Initial examination of the stomach contents of the killed mink whales revealed mostly pollack, krill and anchovy. The complete results of the study will be presented at next year’s IWC meeting.

Japan also catches about 1,000 whales in the Antarctic Ocean and the northwest Pacific Ocean each year under another IWC research programme.

Minke Whale Facts

· Once perceived as asingle species, the minke whale population has quite recently been recognized as consisting of two distinct species: the Northern Mink Whale, Balaenoptera acutorostrata, and the Southern Mink Whale, Balaenoptera bonaerensis.

· Also known as Little Piked Whales or Lesser Rorquals, Mink Whales prefer icy waters but are found world-wide.

· Balaenoptera acutorostrata is listed as Least Concern on the IUCN Red List of Threatened Species, while Balaenoptera bonaerensi is listed as Data Deficient since it was recognized as a separate species so recently.

· Together, the two species are believed to form a population of over 1 million Minke Whales world-wide.

One of the most controversial environmental issues of the past decade now seems to have been solved thanks to the consolidated efforts of one U.S. and one U.K. researcher.

In the late 1980s and early 1990s, researchers started getting reports of numerous deformed wild frogs and toads. Many of them missed a limb partly or completely, while others – even more strikingly – had extra legs or extra arms.

The reason behind the deformities became a hot-potato, with some people suspecting chemical pollution or increased UV-B radiation (brought on by the thinning of the ozone layers), while others leaned towards predators or parasites.

“There was a veritable media firestorm, with millions of dollars of grant money at stake,” says Stanley Sessions, an amphibian specialist and professor of biology at Hartwick College, in Oneonta, New York.
Eventually, professor Sessions and other researchers managed to show that many amphibians with extra limbs were actually infected by small parasitic flatworms called Riberoria trematodes. These nematodes burrow into the hindquarters of tadpoles and rearrange the limb bud cells. This interferes with limb development, and in some cases the result is an extra arm or leg.

While these findings explained the conspicuous presences of additional limbs, it wasn’t enough to solve the mystery of the leg- and armless amphibians.

“Frogs with extra limbs may have been the most dramatic-looking deformities, but they are by far the least common deformities found,” Sessions explains. “The most commonly found deformities are frogs or toads found with missing or truncated limbs, and although parasites occasionally cause limblessness in a frog, these deformities are almost never associated with the trematode species known to cause extra limbs.”

To investigate the conundrum, Sessions teamed up with UK researcher Brandon Ballengee of the University of Plymouth. As a part of a larger research project, the two scientists placed tadpoles in aquariums and added various predators to see if any of them could be responsible for this type of injuries.

As it turned out, three different species of dragonfly nymph happily attacked and nicked of the hind legs of the tadpoles; feasting on the tasty legs without actually killing the tadpoles.

“Once they grab the tadpole, they use their front legs to turn it around, searching for the tender bits, in this case the hind limb buds, which they then snip off with their mandibles,” says Sessions. “Often the tadpole is released […],” says Sessions. “If it survives it metamorphoses into a toad with missing or deformed hind limbs, depending on the developmental stage of the tadpole.”

Eating just a leg instead of trying to kill the entire tadpole is beneficial for the dragonfly, since tadpoles develop poison glands in their skin much earlier than those in their hind legs.

Through surgical experiments, Sessions and Ballengee confirmed that losing a limb at a certain stage of a tadpole’s life can lead to missing or deformed limbs in the adult animal. Really young tadpoles are capable of growing a new limb, but they loose this ability with age.

Sessions stresses that the results of his study doesn’t completely rule out chemicals as the cause of some missing limbs, but says that this type of “selective predation” by dragonfly nymphs is now by far the leading explanation.

“Are parasites sufficient to cause extra limbs?,” he asks. “Yes. Is selective predation by dragonfly nymphs sufficient to cause loss or reduction of limbs. Yes. Are chemical pollutants necessary to understand either of these phenomena? No.”

You can find Sessions and Ballengee’s study in the Journal of Experimental Zoology Part B: Molecular and Developmental Evolution.

You have probably noticed it if you’ve ever tried to catch a fish using your bare hands or a small net: the uncanny ability of these creatures to escape, sometimes even before you make a move. Most fish species are incredibly fast and seem to be virtual mind-readers when it comes to predicting when and where you will make your next attempt.

The reason behind this remarkable talent is a special circuit present in the brains of many species of fish. Fish ears constantly sense the sound pressure on each side of the body and if the ear on one side detects a disturbance, the muscles of the fish will automatically bend the body into a c-shape facing the opposite direction. This involuntary reaction makes it possible for the fish to start swimming way from harms way as quickly as possible. Scientists call it C-start and it is highly advantageous when escaping from predators. That is, until you venture upon the Tentacled snake (Erpeton tentaculatum) of South-East Asia.

While studying the Tentacled snake, Kenneth Catania, associate professor of biological sciences at Vanderbilt University, realized that this snake has found a way of exploiting the C-start reflex to its advantage.

Using video recordings of snake (see below) and prey Catania was able to slow down the chain of events enough to make them noticeable for a human eye, and what he saw amazed him. Instead of fleeing from the snake, fish would swim right into the mouth of the predator nearly four times out of five. How could this be?

When hunting, the Tentacled snake forms its body into a peculiar J-shape with its head at the bottom of the “J”. It then remains absolutely still until suitable prey ventures close enough to the “hook”-area of the J. When it finally strikes, it rarely misses since the fish seem to be magically drawn to the jaws of their attacker. In 120 attacks carried out by four different snakes, Catania observed no less than 78 percent of the fish turning toward the snake’s head instead of swimming away from it.

Catania also noticed something else: before the snakes moved their head to strike, they always flexed a point midway down the body. A hydrophone placed in the aquarium unveiled that by flexing its body, the snake produces sound waves intense enough to trigger the fish’s C-start reflex, and since the sound comes from a spot opposite the head of the hungry snake, the C-start reflex forces the fish to turn and swim directly towards the snake’s mouth.

“Once the C-start begins, the fish can’t turn back,” Catania explained. “The snake has found a way to use the fish’s escape reflex to its advantage. I haven’t been able to find reports of any other predators that exhibit a similar ability to influence and predict the future behavior of their prey,”

The C-start behaviour is actually so predictable that the snake doesn’t even bother to aim for the initial position of its prey and then adjust its direction as most predators would. Instead, it goes directly for the spot where it knows the fish will be heading.

“The best evidence for this is the cases when the snake misses,” says Catania. “Not all the targeted fish react with a C-start and the snake almost always misses those that don’t react reflexively.”

Kenneth Catania studies the brains and behaviour of species with extreme specializations. His new snake study is published this week in the online early edition of the journal Proceedings of the National Academy of Sciences.

Of the 679 whales Japan reported killing during the hunt of 2008/2009, 304 were female. 192 of them were pregnant and four were lactating.

“The four lactating females would each have had a calf that would have starved to death,” said Michael Kennedy, director of the Humane Society International Australia.

The details of Japan’s impact on female whales was contained in what is known as a “Cruise Report”, secretly sent to the IWC’s* scientific committee before the IWC meeting in Portugal this week.

Japan claims that its whaling is legal, scientific research, but many opponents have spoken out against what they see as an unnecessary slaughtering of animals under the guise of science.

“They report they measure the length and weight of the foetus, they measure their eyes and take skin samples from the foetus for what they call genetic studies,” said Kennedy. “It is gruesome, useless information which, if it was even needed, could be found without dismembering a foetus.”

Australian Environment Minister Peter Garrett, who is attending the IWC meeting in Portugal, said Japan had killed more than 13,000 whales in the name of science IWC banned commercial whaling in 1986.

* International Whaling Commission

Australia and New Zealand announced Thursday that they will carry out a six-week long non-lethal whale research expedition in the Antarctic early next year. Dubbing the expedition non-lethal is a direct challenge to Japan’s research program that kills up to 1,000 whales a year.

Iceland and Norway are the only two countries openly defying the IWC ban on commercial whaling; Japan is instead using a lope whole that allows for “lethal research”. Whale meat resulting from the Japanese research is sold for human consumption and many critics claim that this is the real motive behind the program.

In a joint statement, Australia and New Zealand announced their intentions to reform science management within the International Whaling Commission, which holds its annual meeting in Madeira, Portugal, next week, and end Japan’s “so-called scientific whaling.”

“This expedition and the ongoing research program will demonstrate to the world that we do not need to kill whales to study and understand them,” said Australian Environment Minister Peter Garrett.

The expedition aims to increase our knowledge of population structures, abundance, trends, distribution, and the ecological role of whales in the Southern Ocean.

During the latest Japanese hunt, which ended in April, 679 minke whales and one fin whale was killed over a period of five months.

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. “

Scientists tagging sharks off the Irish coast have tagged a surprisingly high number of Basking sharks this year: 50 specimens in just three days.

“I would normally expect to be lucky if we tagged 50 in a whole year,” said Dr Simon Berrow of the Irish Whale and Dolphin Group.

Basking SharkA record

Together with National Parks and Wildlife Service conservation ranger Emmett Johnston, Dr Berrow set out earlier this week to tag sharks off Donegal, as part of a project funded by the Heritage Council.

“In two hours last Monday we tagged 23 sharks, and we found 19 the following day – four of which had been tagged the day before,” Dr Berrow said. By the third day, they had tagged their 50^th basking shark.

Basking sharks were once a significant source of income for Irish whalers and the coastal towns of Galway and Waterford did for instance have street lights lit with basking shark oil as early as the 18^th century.

The importance of Basking sharks in Irish culture is evident in the number of names and monikers give to these peculiar creatures. In Irish, this “monster with sails” is known under the names Liabhán chor gréine (Great fish of the sun), Liop an dá (unwieldy beast with two finns) and Liabhán mór (great leviathan) – just to mention a few. The epithets “Fish of the sun” and “Sunfish” both pertains to its fondness of swimming just under the surface.

In the mid-1970s the Irish stopped their whaling, but the problems weren’t over for these sharks since they frequently ended up as by-catch in drift nets; a fishing method now outlawed in Irish waters. In addition to this, Norwegian whalers continued to hunt for shark off the Irish coast until 1986.

The Basking shark (Cetorhinus maximus) is listed as Vulnerable on the IUCN Red List of Threatened Species, and is a protected species in Great Britain but not in Ireland. However, the European Union has just placed a moratorium on fishing for Basking sharks in these waters.

If you spot a Basking shark in Irish waters, the Irish Whale and Dolphin Group would very much like to know any details about the sighting. You can find more information at www.baskingshark.ie.

Want to know more about Basking sharks and where they head when the Northern Seas become too cold for comfort? Check out our earlier blog post on Sharks of the Caribbean.

The intricate symbiotic relationship between reef building corals and algae seem to rely on a delicate communication process between the algae and the coral, where the algae is constantly telling the coral that the algae belongs inside it, and that everything is fine. Without this communication, the algae would be treated as any other invader, e.g. a parasite, and be expelled by the coral’s immune system.

Researchers now fear that increased water temperature will impair this communication system, something which might prove to be the final blow for corals already threatened by pollution, acidification, overfishing, dynamite fishing, and sedimentation caused by deforestation.

According to a new report, a lack of communication is likely to be the underlying cause of coral bleaching and the collapse of coral reef ecosystems around the world.

Reef building corals can defend themselves and kill plankton for food, but despite this they can not survive without the tiny algae living inside them. Algae, which are a type of plants, can do what corals can’t – use sunlight to produce sugars and fix carbon through photosynthesis.

“Some of these algae that live within corals are amazingly productive, and in some cases give 95 percent of the sugars they produce to the coral to use for energy,” said Virginia Weis, a professor of zoology at Oregon State University. “In return the algae gain nitrogen, a limiting nutrient in the ocean, by feeding off the waste from the coral. It’s a finely developed symbiotic relationship.

If this relationship were to collapse, it would be death sentence for the reef building corals.

Even though the coral depends on the algae for much of its food, it may be largely unaware of its presence, said Weis. We now believe that this is what’s happening when the water warms or something else stresses the coral – the communication from the algae to the coral breaks down, the all-is-well message doesn’t get through, the algae essentially comes out of hiding and faces an immune response from the coral.”

This internal communication process, Weis said, is not unlike some of the biological processes found in humans and other animals.

Researchers now hope that some of the numerous species of reef building corals found globally and their algae will be more apt at handling change.

“With some of the new findings about coral symbiosis and calcification, and how it works, coral biologists are now starting to think more outside the box,” Weis said. “Maybe there’s something we could do to help identify and protect coral species that can survive in different conditions. Perhaps we won’t have to just stand by as the coral reefs of the world die and disappear.”

The new research has been published in the most recent issue of the journal Science and was funded in part by the U.S. National Science Foundation.