Dolphins chew puffer fish to get 'high'!


Dolphins have been filmed chewing on toxic puffer fish, apparently to enjoy their 'narcotic-like effect'.

The footage was shot using cameras disguised as other sea creatures for the BBC series Dolphins: Spy in the Pod, from by the award-winning wildlife documentary producer John Downer. It shows dolphins gently chewing on the fish, and passing it between them, before lapsing into a sort of trance, floating just beneath the surface and apparently fascinated by their own reflections.

Although large doses of the toxin produced by puffer fish can be deadly, in small amounts it can produce a narcotic effect — and the dolphins appeared to know exactly how to make the fish release just the right amount to get them 'high'.

It's the first time dolphins have been filmed acting in this way.

The first of the two-part series will be shown on BBC1 on Thursday, January 2, at 8pm.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Four new species found off the coast of Scotland


Four new species of deep sea creature have been discovered off the north west coast of Scotland, exciting researchers who think the presence of three of them could indicate a "cold seep" vent, in which hydrocarbons leak into the water from a fissure in the seabed.

Two species of clam — Thyasira scotiae and Isorropodon mackayi — and a marine worm, which was actually found living inside one of the clams and has yet to be named, were found at a depth of about three quarters of a mile at a suspected cold seep during surveys around the Rockall coast in the north Atlantic by researchers from Marine Scotland.

If confirmed, the cold seep would be the first to be discovered in the area and could lead to controls on fishing.

A large 10cm/4" sea snail (pictured above) which has been named Volutopsius scotiae, was also discovered during the survey, living at a depth of about a mile.

Both Volutopsius scotiae and Thyasira scotiae have been named after the research vessel MRV Scotia, while Isorropodon mackayi has been named after mollusc expert David W Mackay.

Jim Drewery from Marine ­Scotland Science, said: "The discovery of these new species is absolutely incredible, especially when you consider that the sea snail measures a relatively large 4", yet has gone undetected for decades.

"The project we were undertaking was designed to provide advice that would help balance both commercial fishing and conservation interests in the Rockall area.

"The potential cold seep and its dependant community of marine life is a great find as it is just the sort of habitat we were hoping to pick up on these surveys."

Scotland's Environment ­Secretary Richard Lochhead said: "Scottish waters cover an area around five times bigger than our land mass and are miles deep in places...The area where these species were found is not fished and the confirmation of a cold seep is likely to result in the region being closed to bottom contact fishing."

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Amazing images reveal fishes' hidden anatomy


These images are the work of a scientist at Washington University who bleaches and stains the bodies of fish to expose the skeletal tissue through the skin and flesh.

Professor Adam Summers, is the associate director of Comparative Vertebrate Biomechanics at the at the University of Washington and he uses the method as part of his research into skeletal shape.

The fish are collected either as by-catch from fishery operations, incidental mortality during scientific collection, or as part of a study on the developmental trajectory of the fish skeleton.

The technique uses two dyes: Alcian Blue to stain cartilaginous elements a deep blue and Alizarin Red S to turn mineralised tissue crimson.  

The specimen is then lightly bleached with hydrogen peroxide to remove dark pigments, before the flesh is dissolved with Trypsin — a digestive enzyme found in your intestine, which attacks most proteins but not the collagen that holds the skeleton and skin together. To make the skin and remaining connective tissue invisible the entire specimen is then immersed in glycerin, and the result is that the flesh seems to disappear.

The technique is only suitable for specimens less than 1cm in thickness and processing larger animals can take several months compared to just a few days for a small fish.

These images form part of an exhibition called Cleared which is to go on display at Seattle Aquarium. It includes the lumpsucker (pictured above), skate, rays and sculpin.

See more at picturingscience.com
 

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Study shows that damaged reefs can recover


There could yet be some hope for coral reefs according to a study by University of Florida and Caribbean researchers, which indicates that even damaged reefs are capable of recovery.

In a 13-year study in the Cayman Islands, warm ocean temperatures led to bleaching and infectious disease that reduced live coral cover by more than 40 percent between 1999 and 2004. But seven years later, the amount of live coral on the reefs, the density of young colonies and the overall size of corals all had returned to the 1999 state, the study showed.

Much of the reef surrounding Little Cayman Island is protected, so damage from fishing, anchoring and some other human activities is minimised, said UF researcher Chuck Jacoby, who helped with the study.

"Nevertheless, all coral reefs, even those that are well-protected, suffer damage," Jacoby said. "Little Cayman is an example of what can happen, because it is essentially free from local stresses due to its isolation, small human population and generally healthy ecology."

Reefs are under threat from overfishing, coral mining, tourism and coastal development and now global warming is accelerating the destruction.

But the UF study offers hope for coral reefs ─ if humans pay more attention to protecting them.

"In addition to saving the living organisms that make coral reefs their homes, safeguarding the habitats could ensure millions of dollars for the fishing and tourism industries, not to mention maintaining barriers that protect coastal areas and their human inhabitants from tropical storms," said Tom Frazer, a professor of aquatic ecology at UF.

The study was published in the November online publication Public Library of Science, and highlighted in the "Editor’s Choice" section of last month’s issue of the journal Science.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Sea turtle at US aquarium is confiscated


A Green sea turtle that had been on display at the Idaho Aquarium has been removed by Federal Fish and Wildlife officers.

The two aquarium founders who held the required permit to keep the turtle were given a prison sentence earlier this month after pleading guilty to conspiring to harvest, transport and sell Spotted eagle rays and Lemon sharks for exhibit at the aquarium.

Ammon Covino was sentenced to one year and a day in prison, and Chris Conk to four months.

The sea turtle is a federally protected species and a special permit is required to keep them in captivity. The permit to keep the turtle at Idaho Aquarium was revoked following the convictions of Covino and Conk, who have both been removed from the aquarium's board and payroll.

The Idaho Aquarium is a non-profit organisation, which opened in December 2011 and is home to over 250 species of animals and marine life. 

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

New species of dwarf goby discovered


A striking new species of dwarf goby has been discovered in one of the world's newest countries.

The new goby was found off Timor-Leste by researchers from Conservation International (CI). It's the first new species to have been discovered in the country, which gained independence from Indonesia 11 years ago.

Timor-Leste occupies the northeastern half of the island of Timor, which is the eastern-most of the Lesser Sunda Islands in Southeast Asia. It has biogeographic influences of both the Western Pacific as well as the northeastern Indian Oceans and is located in the world’s premier area for marine biodiversity, mainly due to the extraordinary wealth of coral reef organisms.

In August 2012 an assessment was undertaken of the Konis Santana National Park — Timor-Leste's first national park — as part of USAID's Coral Triangle Support Program.

Coral reef fish biodiversity was surveyed from 0-70 m depth at 20 sites and this lovely new goby was among the 741 species of reef fish recorded off Timor-Leste’s northern coast.

It was found in shallow water and has been named Santana's dwarf goby (Eviota santanai), which CI says is "named in honour of Connisso Antonino (commonly known as "Nino Konis" Santana), a national hero in Timor-Leste’s recent struggle for independence."

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad.

Fishing has reduced numbers of reef 'lawnmowers' by more than half


Researchers have produced a landmark report on the state of plant-eating fish on coral reefs around the world.

In the first global assessment of its kind, a science team led by researchers at Scripps Institution of Oceanography at UC San Diego, has produced a report on the impact of fishing on herbivorous fish populations. These fish are vital to coral reef health due to their role in consuming seaweed, making them known informally as the "lawnmowers" of the reef. Without the lawnmowers, seaweeds can overgrow and out-compete corals, drastically affecting the reef ecosystem.

Among their findings, the researchers found that populations of plant-eating fish declined by more than half in areas that were fished compared with unfished sites.

"One of the most significant findings from this study is that we show compelling evidence that fishing is impacting some of the most important species on coral reefs," said Jennifer Smith, one of the co-authors of the study.

"We generally tend to think of fishing impacting larger pelagic fishes such as tuna but here we see big impacts on smaller reef fish as well and particularly the herbivores. This is particularly important because corals and algae are always actively competing against one another for space and the herbivores actively remove algae and allow the corals to be competitively dominant. Without herbivores, weedy algae can take over the reef landscape. We need to focus more on protecting this key group of fishes around the globe if we hope to have healthy and productive reefs in the future."

While these reef fish are not generally commercial fisheries targets, there was clear evidence that fishing was impacting their populations globally.  

The researchers also found that fishing alters the entire structure of the herbivore fish community, reducing the numbers of large-bodied feeding groups such as "grazers" and "excavators" while boosting numbers of smaller species such as algae-farming territorial damselfishes that enhance damaging algae growth.

"We are shifting the herbivore community from one that’s dominated by large-bodied individuals to one that’s dominated by many small fish," said Smith. "The biomass is dramatically altered. If you dive in Jamaica you are going to see lots of tiny herbivores because fishers remove them before they reach adulthood. In contrast, if you go to an unfished location in the central Pacific the herbivore community is dominated by large roving parrotfishes and macroalgal grazers that perform many important ecosystem services for reefs."

The report is published in the journal Proceedings of the Royal Society B (Biological Sciences) and offers key data for setting management and conservation targets to protect and preserve fragile coral reefs.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad.

 

Video: Virtual aquarium where the fish will play with you!


This new interactive aquarium features everything from tiny clownfish to huge whale sharks — and the fish will even follow you about!

"Deep Blue" is an interactive video canvas that uses advanced interactive graphics to create a virtual aquarium.

There are a number of highly-detailed scenes to enjoy:

In the "Coral Reef", giant sea turtles swim through an azure water accompanied by schools of tropical fish that appear from the corals to playfully follow the viewers.

"Deep Blue" simulates marine life at a greater depth, where a number of different shark species circle continuously while the viewers can generate bubbles within the otherwise pristine ocean.

There are also two night scenes: "Tuna", in which large school of tuna glide perpetually through the tank, revealed interactively by a virtual light source projected by the participant. And in "Jelly Fish", an even more surreal and tranquil scene of various jellies mingle playfully with the animated phosphorescent particles that flow freely along with the movement of the viewers.

The Interactive Aquarium is the work of Dominic Harris and London-based Cinimod Studio, which says: "All the scenes have a highly detailed realism to them, and yet on closer inspection one discovers a playful tweaking of nature happening. While in real life the fish tend to flee humans, in the Interactive Aquarium they are actively attracted – and appear to make little performances to the amusement and astonishment of an otherwise unsuspecting viewer."

You can see more in the video below:

 

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad.

 

9 rare fish in stock now at TMC London


If you're still not sure what to ask Santa for this Christmas, check these marine fish out. TMC doesn't sell direct to the public, but if you speak to your retailer quickly enough, they may be able to secure you one of these beauties…

However, given the rarity of many of these in the hobby, they're well sought-after fish, meaning none of them are likely to be cheap. Might be worth getting a price before you place your order...

Many thanks to TMC London for giving us permission to use their pictures.

1. Japanese angelfish (Centropyge interruptus) — pictured at the top of the page

2. Chilled blusher clownfish morphs

3. Conspic angel (Chaetodontoplus conspicillatus)

4. Dr Seuss fish (Belonoperca pylei)

5. Tiger'pyge angelfish (hybrid Centropyge flavissimus x C. eibli)

6. Footballer damsel

7. Pelicier's hawkfish (Plectranthias pelicieri)

8. Tiger tang (Acanthurus polyzona)

9. Wrought iron butterflyfish (Chaetodon daedalma)

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad.

 

First Zebra shark born at The Deep


The Deep aquarium in Hull is celebrating the birth of its first baby Zebra shark.

The female shark, which hatched out last Monday, weighed in at 72 grams and measured 23cm/9" in length. She is growing steadily and is now 25cm/10" long.

Zebra sharks (Stegostoma fasciatum) take a long time to mature, so staff at The Deep were delighted when mating behaviour and "practice eggs" were seen in the aquarium's Endless Oceans display.

These practice eggs do not contain a yolk and are the first signs that a female shark is maturing.

After a few months an egg containing a yolk was finally produced and this was transferred to a holding tank in The Deep's quarantine area. The gestation period for the Zebra shark is about six months in the egg, so it was a bit of a waiting game for excited staff at the aquarium.

Kathy Duke, Curator at The Deep said: "We used a technique called 'candling', which is where you shine a light through the egg casing under water and we were absolutely delighted to see a shark embryo in there.

Later on in her development, our vet and science officer used an ultrasound to take a better look inside the egg and was able to measure the size of the baby shark's heart which was 6mm in diameter — the size of a pea.

"Although these first few months are a delicate time, she is enjoying feeding on prawns and mussels. We have taken advice from colleagues in America on feeding and growth rates, so we are able to provide the best possible care."

When Zebra sharks hatch they have black and white stripes, which develop into more of a leopard pattern later in life, giving them their other name of Leopard shark.

The Deep currently holds the European studbook for Zebra sharks, which helps co-ordinate all the breeding efforts for this species across Europe, sharing vital knowledge on their reproductive biology.

The young shark will remain at The Deep while her growth rates are closely monitored. If all goes well she's likely to be transferred to another aquarium at a later date so she can be paired with an unrelated male Zebra shark and one day hopefully produce some eggs of her own.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Thousands of fish evacuated from Norfolk aquarium


A major operation to rescue more than 3,000 fish at Hunstanton Sea Life Sanctuary got underway on Friday morning after power to vital life support systems was lost during severe flooding in Norfolk.

Staff worked through the night after the sea breached defences and flooded the building to a depth of more than a foot throughout, and fire officers were still pumping water out on Friday morning.

Special transport vehicles with their own life support were sent from Sea Life's Dorset headquarters to provide emergency back-up, and begin the operation to remove the fish.

The majority were safely removed on Friday. Sharks were caught in their tank with two divers using nets to steer them towards other staff holding landing nets before being rushed out to a waiting van with aerated tanks.

Some of the evacuees have been settled at Great Yarmouth Sea Life Centre while others were take to quarantine facilities in Weymouth, Dorset. The remaining fish and other animals were expected to be evacuated on Saturday.

The Sanctuary building has suffered serious damage but the full extent is as yet unknown. With a very real prospect that electricity might not be restored to the building for days, all the residents had needed to be moved to alternative facilities as quickly as possible.

Sanctuary General Manager Nigel Croasdale praised the efforts of the fire service and his own staff.

"My displays team and three other staff worked right through the night and we have all been very anxious about the welfare of our resident creatures," he said.

Sea Life reinforcements to help exhausted Sanctuary staff, arrived from as far afield as Blackpool and Alton Towers.

"In spite of our best efforts we were unable to save around a dozen fish," said Sea Life's head marine biologist Rob Hicks.

"They were the older and weaker individuals, including three mackerel and three Pacu," he added.

"We regret every loss of course, but to lose so few in such circumstances as we have faced in the last 48 hours, is testament to the Herculean efforts of everybody involved.

"We'd publicly like to thank the Fire Brigade and the local community that have offered help and refreshments over the last few days."

The Sanctuary is also home to penguins, otters and seals, which are also likely to be relocated until power is restored and necessary repairs undertaken.

The Sanctuary will be closed to visitors until further notice. A full estimate of the extent of the damage is to be carried out over the next few days.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

'Fertility clinic' could save the Great Barrier Reef


Scientists gathered at November's mass coral spawning event in the Great Barrier Reef to collect billions of eggs and sperm in an effort to stop its corals becoming extinct.

This mass spawning is dubbed one of the most spectacular natural events of the year, when over 400 species of coral spew out clouds of tiny egg and sperm bundles in an extraordinary display that attracts tourists from all over the world and becomes a kind of feeding frenzy for marine animals.

The scientists' aim is to freeze the the sperm and embryonic cells in a bank at a coral fertility clinic at Taronga's Western Plains Zoo, so they can be used in the future.

The project is a joint venture involving experts from the Australian Institute of Marine Science (AIMS), Taronga Zoo and the US Smithsonian Institution.

Mary Hagedorn, who is a marine biologist at the Smithsonian Institution, perfected the technique while working with corals in Hawaii.

The plan is to thaw out the genetic material at a later date and use it to grow new coral, which can then be introduced back to the ocean to help restore the reef.

Scientists are also reported to be trying for the first time to grow coral to sexual maturity, which can take up to three years, using eggs taken during the November spawning period and fertilising them with sperm that had been previously frozen.

To ensure corals re-introduced to the the reef have the best chances of success, scientists are using the world-class marine research aquarium facility called the Sea Simulator (SeaSim) as a nursery to rear juvenile corals. This high-tech system, located at the Australian Institute of Marine Science, reproduces the conditions of the ocean.

The coral bank is being supervised by a team headed by Rebecca Spindler, who said: "We know the Great Barrier Reef is in deep, deep trouble. We will never have as much genetic diversity again on the reef as we do right now. This is our last opportunity to save as much as we possibly can."

Since 1985, when AIMS began monitoring more than 100 locations on the reef, coral cover has diminished by an average of 50%. If its current rate of decline continues, it will halve again by 2022.

Climate change, ocean acidification, pollution and industrial development have all played a part in its decline.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Giant crab recovering after five days in the fridge!


An enormous crab, which spent five days in a fridge, has made a miraculous discovery at Bristol Aquarium

The giant Edible crab (Cancer pagurus), measuring 23cm/9" across its carapace and with claws the size of hands had been caught by a fisherman in Dartmouth and then transported to Weston-super-Mare in his car in the hope that the gift would help cheer up a sick friend.

The crab then spent five days in the fridge before the family decided they just couldn't bring themselves to eat it.

Bristol Aquarium’s David Waines said: "We received a phone call from a lady who told us they had a large crab in their fridge and they wanted to donate it to the aquarium.

"Basically, they didn’t have the heart to kill him. Additionally, they decided they did not have a saucepan big enough to cook him in!

"When she told me it had been in there for five days I couldn’t believe it was still alive. I told them to wrap it in a wet towel and bring it along to the aquarium as quickly as possible.

"Although the crab was very weak when it arrived the fact that it was kept refrigerated meant it was in a kind of suspended animation.

"We placed it into a special tank in our quarantine area and began pumping oxygen-rich seawater over it and it immediately started to show signs of recovery.

"Hopefully it will continue to get better and will be able to enjoy an unexpectedly long retirement here at the aquarium," he added.

The Edible crab is Britain’s largest species of crab. Tests have shown that its claws have the crushing strength of over 90 pounds per square inch. An average person’s hand is only capable of squashing to 25 lb per square inch.

They also use them to crush prey, such as shellfish as well as in fights with other crabs in which they can losing their claws, re-growing them at the next moult.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Aquarium operators jailed for fish trafficking


Two of the operators of the Idaho Aquarium in the US have been sentenced in court for conspiring to harvest, transport and sell Spotted eagle rays and Lemon sharks for exhibit at the aquarium.

Ammon Covino (40) president of the Idaho Aquarium and also one of its founders, was sentenced to one year and a day in prison, followed by a term of supervised release of two years. He was also barred by the Court from any employment during the period of supervised release that involves the possession, display, transportation, exhibition, purchase, or sale of wildlife.

Christopher Conk (40), the aquarium's secretary, who co-operated with investigators, received a reduced sentence of four months in prison followed by two years of supervised release for his role in bringing the sharks and rays to Idaho. He will also forfeit the truck used to transport the fish from the airport. Reportedly, Conk had previously pleaded guilty to smuggling protected coral.

Over a period of several months in 2012, Covino and Conk engaged in a conspiracy to purchase and transport wildlife from the Florida Keys to Idaho for exhibit at the Idaho Aquarium in Boise. The wildlife included Spotted eagle rays and Lemon sharks, which required Florida licenses and permits never acquired by the participants in the deals.

Despite being advised of the requirements of the law by the seller — who later reported the incident to the authorities — they directed their Florida-based suppliers to ignore it and make the shipments without the necessary paperwork.

However, Covino and Conk were unaware that their phone conversations and text messages were being recorded by the business owner, who was co-operating with federal authorities.

The Spotted eagle rays and Lemon sharks were captured in the Keys by marine-life collectors in mid-2012. The rays sold for $1,250 each, the sharks for $650 each.

Payment for the various specimens was made by credit cards held in the Aquarium's name. The defendants acknowledged that their illegal conduct was within the scope of their employment, and intended to benefit, at least in part, the Idaho Aquarium. In the same case, Idaho Aquarium, Inc. pled guilty to the same conspiracy count and is awaiting sentencing.

In a separate criminal proceeding, Peter Covino, the nephew of Ammon Covino, was tried, convicted, and sentenced for obstruction of justice in connection with his effort to persuade the supplier in the Florida Keys to destroy the invoices and messages related to the illegal purchases of the marine life to prevent their use in Ammon Covino’s case.

Testimony at the trial established that after Ammon Covino had been arrested in February this year, he induced Peter Covino to make the calls.

The Idaho Aquarium is a non-profit organisation, which opened in December 2011 and is home to over 250 species of animals and marine life.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

The Deep named as world's second best aquarium


The Deep in Hull has come second in a list of the top aquariums in the world.

Canadian website The Richest recently ran a feature looking at the world's most amazing aquariums.

And it placed The Deep in second spot, behind the Dubai Aquarium but ahead of the Georgia Aquarium in Atlanta!

Colin Brown, The Deep's chief executive told The Hull Daily Mail: "We would have been over the moon to make the top ten, let alone be number two."

The Richest said:"The Deep Aquarium may not be the most impressive in terms of size, but nevertheless, it is still one of the most impressive. Strictly speaking, The Deep Aquarium is actually a submarium. It has tanks filled with 2.5 million litres of seawater. It plays host to seven varieties of shark species, as well as more than 3,500 different kinds of sea animals and creatures. The aquarium opened in 2002 and has been a major tourist destination since it started its operations. The general public funds the place, and it also plays an important role in marine research through its modern aquatic laboratories."

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

New species of giant clam discovered


A vivid new species of giant clam has been discovered on reefs in Western Australia and the Solomon Islands.

What's surprising is that the new species has been hiding in plain sight all along, as it looks very similar to Tridacna maxima.

Researchers collected samples of tissues from giant clams at up to 20m depth around Solomon Islands and Ningaloo Reef and found the specimen they thought was T. maxima was actually genetically quite different.

Jude Keyse, a School of Biological Sciences postgraduate student at the University of Queensland said: "Giant clams can grow up to 230kg and are some of the most recognisable animals on coral reefs, coming in a spectrum of vibrant colours including blues, greens, browns and yellow hues.

But she explained that the discovery of the new species had implications for management of giant clams.

"What we thought was one breeding group has turned out to be two, making each species even less abundant than previously thought," she said.

Charles Darwin University postgraduate student Mr Shane Penny, who co-authored the paper published in the open access journal PLoS One said identifying a new species within a well-known group such as giant clams was a unique opportunity for a student.

"To correctly describe the new species now becomes critical as the effects of getting it wrong can be profound for fisheries, ecology and conservation," he said.

Giant clams are beloved by divers and snorkelers but also prized as a source of meat and shells.

Overconsumption by humans has depleted giant clam populations in many areas and most species are on the International Union for Conservation of Nature (IUCN ) Red List of Threatened Species.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Study sheds more light on life of land-dwelling blenny


A tiny fish that lives on land uses camouflage to shun attacks by predators such as birds, lizards and crabs.

Scientists from the University of NSW in Australia studied this unique fish species — the Pacific leaping blenny (Alticus arnoldorum) — in its natural habitat on the tropical island of Guam.

The Pacific leaping blenny grows to around 4-8cm and gets its name from its ability to leap using a tail-twisting behaviour. They are also capable of jumping many times their own body weight to reach higher ground.

These blennies remain on land all their adult life, living on the rocks in the splash zone where they defend their territories, feed and court mates. But they have to stay moist to be able to breathe through their gills and skin.

"They offer a unique opportunity to discover in a living animal how the transition from water to the land has taken place," says Dr Ord, of the UNSW School of Biological, Earth and Environmental Sciences.

The researchers first measured the colour of five different populations of the fish around the island and compared this with the colour of the rocks they lived on. "They were virtually identical in each case. The fish’s body colour is camouflaged to match the rocks, presumably so they aren’t obvious to predators," says Dr Ord.

To see if background matching reduced predation, the researchers created realistic-looking models of blennies out of plasticine, putting lots of these model blennies on the rocks where the fish live, as well as on an adjacent beach where their body colour against the sand made them much more conspicuous to predators.

"After several days we collected the models and recorded how often birds, lizards and crabs had attacked them from the marks in the plasticine. We found the models on the sand were attacked far more frequently than those on the rocks," Dr Ord explained.

"This means the fish are uniquely camouflaged to their rocky environments and this helps them avoid being eaten by land predators."

The researchers then studied the body colour of closely related species of fish, some of which lived in the water and some of which were amphibious, sharing their time between land and sea.

"These species provide an evolutionary snapshot of each stage of the land invasion by fish," says Dr Ord.

The similarities in colour between these species and the land-dwelling fish suggest the ancestors of the land-dwelling fish already had a colouration that matched the rocky shoreline before they moved out of the water, which would have made it easier for them to survive in their new habitat.

The study by Dr Terry Ord and Courtney Morgans, of the Evolution and Ecology Research Centre will be published in the journal Animal Behaviour.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Video: Two rare clownfish morphs at TMC


Tropical Marine centre recently took delivery of two pairs of Gladiator clowns and three pairs of Nugget clowns - the only pairs of each of these morphs in the UK. You can see both in the videos below.

Unfortunately for the fans of clownfish morphs out there, these have already been snapped up.

Please note that TMC supplies to the trade only.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone

 

 

Reef fish find it's too hot for swimming


We all know the feeling, it’s a hot summer afternoon and you have no appetite and don’t want to do anything apart from lay on the couch. A team of researchers from the ARC Centre of Excellence for Coral Reef Studies at James Cook University has shown that ocean warming may make some large reef fish feel the same way.

Researcher Dr Jacob Johansen said that fish rely on swimming for almost all activities necessary for survival, including hunting for food and finding mates.

"However, global warming may reduce the swimming ability of many fish species, and have major impacts on their ability to grow and reproduce," he said.

Dr Johansen said that research aimed at understanding the impact of global warming on Coral trout (Cephalopholis miniata) revealed that increasing ocean temperatures may cause large fish to become lethargic, spending more time resting on the bottom and less time swimming in search for food or reproductive opportunities.

He said that the study he and his colleagues had undertaken showed that even when individuals do muster up enough energy to swim around, they swim at a much slower rate. This lower activity is likely to directly impact their ability to catch food, or visit spawning sites.

"The loss of swimming performance and reduced ability to maintain important activities, like moving to a spawning site to reproduce, could have major implications for the future distribution and abundance of these species," Dr Johansen said.

But there was some evidence that Coral trout may be able to adapt to increasing temperatures.

"Populations from the northern region of the Great Barrier Reef were a little better than southern populations at tolerating these conditions," he said.

The Coral trout is a commercially important fish species. The research team is planning further experiments to clarify its ability to adapt to the rapid changes caused by global warming or whether it could be forced to relocate to cooler more southerly waters.

The study is published in the latest issue of the journal Global Change Biology.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.

 

Video: Seahorses are 'amazing predators'


Ever thought of a seahorse as a ferocious predator? Probably not, but recent research shows that their skills at catching prey are pretty amazing - and it's all in the head!

"A seahorse is one the slowest swimming fish that we know of, but it’s able to capture prey that swim at incredible speeds for their size," said Brad Gemmell, research associate at the University of Texas Marine Science Institute.

Seahorses and other syngnathids such as pipefish, are extremely fond of copepods. These tiny crustaceans escape predators when they detect waves produced in advance of an attack, and they can jolt away at speeds of more than 500 body lengths per second. That equates to a 6'/1.8m person swimming under water at 2,000 mph.

Under calm conditions it was found that seahorses caught their intended prey 90% of the time — better than any of the fish tested.

Using high-speed digital 3-D holography techniques, researchers then studied the Dwarf seahorse (Hippocampus zosterae) and some copepods in action (scroll down for video).

What they found was that the seahorse’s head is shaped to minimise the disturbance of water in front of its mouth before it strikes. Just above and in front of the seahorse’s nostrils is a kind of "no wake zone", and the seahorse angles its head precisely in relation to its prey so that no fluid disturbance reaches it.

"It’s like an arms race between predator and prey, and the seahorse has developed a good method for getting close enough so that their striking distance is very short," Gemmell said.

Seahorses feed by a method known as pivot feeding. They rapidly rotate their heads upward and draw the prey in with suction. The suction only works at short distances; the effective strike range for seahorses is about 1mm. And a strike happens in less than one millisecond. Copepods can respond to predator movements in 2-3 milliseconds — faster than almost anything known, but not fast enough to escape the strike of the seahorse.

In the video below, you can watch a seahorse sneak up on a copepod and use its "pivot feeding" technique to suck the copepod into its mouth.

"People don't often think of seahorses as amazing predators, but they really are," Gemmell added.

The study is published in Nature Communications.

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad/iPhone.