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Enormous goldfish and other pet fish have been found in the rivers of Australia by researchers who believe they were released by their owners.
The common misconception of the goldfish as a small, domesticated species best suited to an aquarium has been challenged yet again by scientists who have warned of their damaging impact on natural ecosystems.
Researchers at Murdoch University in Perth have caught goldfish which tipped the scales at up to 2kg and grew up to 30cm.
They have warned that goldfish and other abandoned species such as koi carp are destroying habitats for native breeds of fish by eating their spawn and uprooting plants and sediment on the river bed.
Stephen Beatty, a researcher from the Centre of Fish and Fisheries at Murdoch University, started tagging feral goldfish in the Vasse River near Perth and monitoring their movements.
“We used acoustic telemetry, which is the same technology used to track sharks off the coast, just on a much smaller scale,” he told Perth Now.
“We tracked 15 mature fish over a year and that informed us about where they were going in their breeding period.”
Introduced species such as goldfish could disturb habitat and consume eggs of native fish, said Dr Beatty. They have also been found to spread a disease which affects the skin of native fish.
Wildlife Photographer of the Year Show all 26 1 /26Wildlife Photographer of the Year Wildlife Photographer of the Year A polar bear's struggle - Highly Commended Justin’s whole body pained as he watched this starving polar bear at an abandoned hunter's camp, in the Canadian Arctic, slowly heave itself up to standing. With little, and thinning, ice to move around on, the bear is unable to search for food.
Justin Hofman / Natural History Museum
Wildlife Photographer of the Year Curious Encounter - Shortlisted Cristobal Serrano, Spain. Any close encounter with an animal in the vast wilderness of Antarctica happens by chance, so Cristobal was thrilled by this spontaneous meeting with a crabeater seal off of Cuverville Island, Antarctic Peninsula. These curious creatures are protected and, with few predators, thrive.
Cristobal Serrano / Natural History Museum
Wildlife Photographer of the Year Bond of brothers - Winner David Lloyd, New Zealand / UK. These two adult males, probably brothers, greeted and rubbed faces for 30 seconds before settling down. Most people never have the opportunity to witness such animal sentience, and David was honoured to have experienced and captured such a moment.The picture was taken in Ndutu, Serengeti, Tanzania.
David Lloyd / Natural History Museum
Wildlife Photographer of the Year Fox meets fox - Highly Commended Matthew Maran, UK. Matthew has been photographing foxes close to his home in north London for over a year and ever since spotting this street art had dreamt of capturing this image. After countless hours and many failed attempts his persistence paid off.
Matthew Maran / Natural History Museum
Wildlife Photographer of the Year Three Kings - Highly Commended Wim Van Den Heever, South Africa. Wim came across these king penguins on a beach in the Falkland Islands just as the sun was rising. They were caught up in a fascinating mating behaviour –the two males were constantly moving around the female using their flippers to fend the other off.
Wim Van Den Heever / Natural History Museum
Wildlife Photographer of the Year One toy, three dogs - Highly Commended Bence Mate, Hungary. While adult African wild dogs are merciless killers, their pups are extremely cute and play all day long. Bence photographed these brothers in Mkuze, South Africa –they all wanted to play with the leg of an impala and were trying to drag it in three different directions!
Bence Mate / Natural History Museum
Wildlife Photographer of the Year Clam Close-up - Shortlisted David Barrio, Spain. This macro-shot of an iridescent clam was taken in the Southern Red Sea, Marsa Alam, Egypt. These clams spend their lives embedded amongst stony corals, where they nest and grow. It took David some time to approach the clam, fearing it would sense his movements and snap shut!
David Barrio / Natural History Museum
Wildlife Photographer of the Year The Orphaned Beaver - Shortlisted Suzi Eszterhas, United States. A one-month-old orphaned North American beaver kit is held by a caretaker at the Sarvey Wildlife Care Center in Arlington, Washington. Luckily it was paired with a female beaver who took on the role of mother and they were later released into the wild.
Suzi Eszterhas / Natural History Museum
Wildlife Photographer of the Year Ice and Water - Shortlisted Audun Lie Dahl, Norway. The Bråsvellbreen glacier moves southwards from one of the ice caps covering the Svalbard Archipelago, Norway. Where it meets the sea, the glacier wall is so high that only the waterfalls are visible, so Audun used a drone to capture this unique perspective
Audun Lie Dahl / Natural History Museum
Wildlife Photographer of the Year Teenager - Shortlisted Franco Banfi, Switzerland. Franco was free diving off Dominica in the Caribbean Sea when he witnessed this young male sperm whale trying to copulate with a female. Unfortunately for him her calf was always in the way and the frisky male had to continually chase off the troublesome calf.
Franco Banfi / Natural History Museum
Wildlife Photographer of the Year Resting Mountain Gorilla - Shortlisted David Lloyd. The baby gorilla clung to its mother whilst keeping a curious eye on David. He had been trekking in South Bwindi, Uganda, whenhe came across the whole family. Following them, they then stopped in a small clearing to relax and groom each other.
David Lloyd / Natural History Museum
Wildlife Photographer of the Year Painted Waterfall - Shorltisted Eduardo Blanco Mendizabal, Spain. When the sun beams through a hole in the rock at the foot of the La Foradada waterfall, Catalonia, Spain, it creates a beautiful pool of light. The rays appear to paint the spray of the waterfall and create a truly magical picture.
Eduardo Blanco Mendizabal / Natural History Museum
Wildlife Photographer of the Year The Extraction - Shortlisted Konstantin Shatenev, Russia. Every winter, hundreds of Steller's sea eagles migrate from Russia, to the relatively ice-free northeastern coast of Hokkaido, Japan. They hunt for fish among the ices floes and also scavenge, following the fishing boats to feed on any discards. Konstantin took his image from a boat as the eagles retrieved a dead fish thrown onto the ice.
Konstantin Shatenev / Natural History Museum
Wildlife Photographer of the Year Shy - Shortlisted Pedro Carrillo, Spain. The mesmerizing pattern of a beaded sand anemone beautifully frames a juvenile Clarkii clownfish in Lembehstrait, Sulawesi, Indonesia. Known as a 'nursery' anemone, it is often a temporary home for young clownfish until they find a more suitable host anemone for adulthood.
Pedro Carrillo / Natural History Museum
Wildlife Photographer of the Year Red, Silver and Black - Shortlisted TinMan Lee, USA. Tin was fortunate enough to be told about a fox den in Washington State, North America, which was home to a family of red, black and silver foxes. After days of waiting for good weather he was finally rewarded with this touching moment.
Tin Man Lee / Natural History Museum
Wildlife Photographer of the Year Isolated - Shortlisted Anna Henly, UK. Snapped from a helicopter, this isolated tree stands in a cultivated field on the edge of a tropical forest on Kauai, Hawaii. The manmade straight lines of the ploughed furrows are interrupted beautifully by nature’s more unruly wild pattern of tree branches.
Anna Henly / Natural History Museum
Wildlife Photographer of the Year Sound Asleep - Shortlisted Tony Wu, USA. This adult humpback whale balanced in mid-water, headon and sound asleep was photographed in Vava’u, Kingdom of Tonga. The faint stream of bubbles, visible at the top, is coming from the whale’s two blowholes and was, in this instance, indicative of an extremely relaxed state.
Tony Wu / Natural History Museum
Wildlife Photographer of the Year All That Remains - Shortlisted Phil Jones, UK. A male orca had beached itself about a week before Phil’s visit to Sea Lion Island, Falkland Islands. Despite its huge size the shifting sands had almost covered the whole carcass and scavengers, such as this striated caracara, had started to move in.
Phil Jones / Natural History Museum
Wildlife Photographer of the Year Ambush - Shortlisted Federico Veronesi, Kenya. On a hot morning at the Chitake Springs, in Mana Pools National Park, Zimbabwe, Federico watched as an old lioness descended from the top of the riverbank. She’d been lying in wait to ambush any passing animals visiting a nearby waterhole further along the riverbed.
Federico Veronesi / Natural History Museum
Wildlife Photographer of the Year Gliding - Shortlisted Christian Vizl, Mexico. With conditions of perfect visibility and beautiful sunlight, Christian took this portrait of a nurse shark gliding through the ocean off the coast of Bimini in the Bahamas. Typically these sharks are found near sandy bottoms where they rest, so it’s rare to see them swimming.
Christian Vizl / Natural History Museum
Wildlife Photographer of the Year Otherworldly - Shortlisted A school of Munk's devil ray were feeding on plankton at night off the coast of Isla Espíritu Santo in Baja California, Mexico. Franco used the underwater lights from his boat and a long exposure to create this otherworldly image.
Franco Banfi / Natural History Museum
Wildlife Photographer of the Year The Bat’s Wake - Shortlisted Antonio Leiva Sanchez, Spain. After several months of field research into a little colony of greater mouse-eared bats in Sucs, Lleida, Spain, Antonio managed to capture this bat mid-flight. He used a technique of high speed photography with flashes combined with continuous light to create the ‘wake’.
Antonio Leiva Sanchez / Natural History Museum
Wildlife Photographer of the Year Under the Snow - Shortlisted Audren Morel, France. Unafraid of the snowy blizzard, this squirrel came to visit Audren as he was taking photographs of birds in the small Jura village of Les Fourgs, France. Impressed by the squirrel’s endurance, he made it the subject of the shoot.
Audren Morel / Natural History Museum
Wildlife Photographer of the Year Unique Bill - Shortlisted Rob Blanken, The Netherlands. The pied avocet has a unique and delicate bill, which it sweeps like a scythe, as it sifts for food in shallow brackish water. This stunning portrait was taken from a hide in the northern province of Friesland in The Netherlands.
Rob Blanken / Natural History Museum
Wildlife Photographer of the Year Family Portrait - Shortlisted Connor Stefanison, Canada. A great grey owl and her chicks sit in their nest in the broken top of a Douglas fir tree in Kamloops, Canada. They looked towards Connor only twice as he watched them during the nesting season from a tree hide 50 feet (15 metres) up.
Connor Stefanison / Natural History Museum
Wildlife Photographer of the Year A dog jumps to catch a disc during a dog frisbee competition in Poznan
via REUTERS
“They can stir up sediment, increasing turbidity, and they can re-suspend nutrients through their feeding activity because they cruise along the bottom hoovering sediment which can uproot plants as well,” he said.
“The key is really preventing it and getting the message out there that people shouldn’t be releasing freshwater fish in artificial wetlands."
The issue of goldfish growing to unmanageable sizes after being released by disenchanted owners has prompted action by governments around the world, with Canada slapping down a fine of £51,000 for those who release live fish into certain lakes and rivers.
A goldfish measuring 41cm and weighing 2.3kg was found in a pond in Poole in the UK six years ago, while another died after living to an impressive 43 years old.
The largest goldfish recorded was 48 cm long and found in the Netherlands in 2008.
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