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River and lake
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  (07-04-2018, 04:18 AM)Pantherinae Wrote:(06-18-2017, 12:55 AM)Pckts Wrote: Beautiful Festae, Haitiensis and Dovii Pairs Ive had a dovii to the 8” stage but I’ve seen many big boys and they all were mean as could be. I’ve never seen a black nasty in person though, when I get back into the game I’m either getting a Haitiensis or a Beanii I think. (07-04-2018, 06:37 PM)Pckts Wrote:Awsome I’ve had a 10 inch Dovii! Insane fish, gave it to a friend with a massive aquarium with catfish, arowana and pacu. he put a female with my male and it went fine for a while, then they killed the whole tank in one night! Haitiensis are awsome had one pair that I just sold. Can’t have any fish at the moment it sucks, but hopfully when my house is finished I can get a large tank and grow a 24’ Dovii that is the dream!(07-04-2018, 04:18 AM)Pantherinae Wrote:(06-18-2017, 12:55 AM)Pckts Wrote: Beautiful Festae, Haitiensis and Dovii Pairs 
Wildlife Along Indian Rivers.
Source: Natureinfocus.in Artist: Rohan Chakravarty  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
14-foot fish spotted in river, giving hope to vanished giant’s return
 *This image is copyright of its original author Atlantic sturgeon were once plentiful but then nearly wiped out. Are they making a comeback? Photograph by Joel Sartore, National Geographic Photo Ark/Nat Geo Image Collection Sonar readings from New York's Hudson River hint at a revival for the embattled Atlantic sturgeon. 7 Minute Read Quote:This article was created in partnership with the National Geographic Society. Cold Spring, New YorkOne day last June, two researchers were towing a special sonar system up and down the Hudson River near Hyde Park, New York, the site of President Franklin Delano Roosevelt’s home, when they saw something pleasantly shocking. They were helping state biologists assess whether the spawning or foraging of a fabled and endangered bottom-feeding denizen, the Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus), was being disrupted when commercial vessels dropped anchor in a spot designated as a waiting area to manage ship traffic. The anchorage, established in 1999, happened to be located in a stretch of the Hudson that is one of the most important spawning grounds in its range along the coast from Florida through Canada’s maritime provinces. More anchorages were planned elsewhere in the Hudson. Unlike a simple depth sounder, this “side-scan” sonar sweeps high-frequency beams of sound out at angles, producing a detailed three-dimensional portrait of the river bed and any decent-size fish—and often precise enough to reveal the sturgeon’s distinctive profile, as low-slung as a Formula One car. John A. Madsen, the University of Delaware geologist running the sonar, recalled the screen was showing the expected mix of bottom features—areas where currents had sculpted “sand waves,” scrapes and furrows in the anchorage. Here and there they could see the scattering of adult sturgeon expected at this time of year. And then there was the big one. River giant The sonar revealed a sturgeon roughly twice as long as anything seen that day—confidently estimated at just over 14 feet from nose to tail tip. That’s a size that, even decades ago, even a century ago, was considered a rarity. But now, it was unimaginable given what this species had endured. “When I first saw it, I said, ‘You’ve got to be kidding me,’” Madsen recalled. But there was no mistaking the image. He and his colleague, Dewayne A. Fox of Delaware State University, have extensively used this sonar system in sturgeon habitat elsewhere along the Atlantic Coast and in the Republic of Georgia, home to half a dozen species of sturgeon, all deeply endangered, including Huso huso, which can reach lengths of 18 feet and is the source of Beluga caviar. Amanda Higgs, a state biologist who’s been tagging and netting Hudson sturgeon for more than a decade, was out on the water working nearby that day. As news of the sighting spread, she had a reaction echoing a famed scene in the movie Jaws. “Our boat is way too small to deal with a fish like that,” she said in an email. Biologists estimate a sturgeon that length could easily weigh 800 pounds. One exciting aspect of knowing the Hudson has female sturgeon that large is that bigger females produce vastly more eggs than smaller ones—up to 8 million at the high end. “Size matters,” said Jane Lubchenco, a marine ecologist at Oregon State and a former administrator of the National Oceanic and Atmospheric Administration. The debate over adding anchorages along the Hudson is on hold for now after fierce opposition from environmental groups and scientists, including a cautionary 2016 letter to the Coast Guard from Madsen and Fox, who’ve been doing surveys around Hyde Park for several years. But any harm from dragging anchors would be just one of a host of far broader assaults on this species, and sturgeon worldwide, over the last century. “The most threatened group of animals” In 2010, the International Union for Conservation of Nature was blunt in its warning: “Eighty five percent of sturgeon, one of the oldest families of fishes in existence, valued around the world for their precious roe, are at risk of extinction, making them the most threatened group of animals on the IUCN Red List of Threatened Species.”  *This image is copyright of its original author This side-scan sonar image from the Hudson River reveals Atlantic sturgeon in new detail. Photograph by John Madsen, University of Delaware Arne Ludwig, who is the co-chair of the IUCN Sturgeon Specialist Group and a biologist at the Leibniz Institute for Zoo and Wildlife Research in Berlin, says the status of sturgeon and their paddlefish kin is unchanged, although he pointed to promising reintroduction plans for Atlantic sturgeon, for instance, in some European waters where they were extirpated long ago. Any recovery in the Hudson and elsewhere along the East Coast will inevitably take time. The Atlantic sturgeon can take a couple of decades to reach spawning age. Erica Ringewald, a spokeswoman for the New York State Department of Environmental Conservation, said the sighting of the giant fish, along with data from the annual tagging studies and rising counts of juvenile sturgeon, “bolstered the case that New York’s actions to protect this fish more than two decades ago with a moratorium are working.” She added that the state hoped to expand the sonar scans to the rest of the river. But independent biologists told me they were far more downbeat, chastened by the scope of losses. In the Hudson and other American waters, the fishery for Atlantic sturgeon has seen spasmodic waves of depredation, particularly during a caviar craze in the late nineteenth century and then several more times in the 20th century. Albany beef This rhythm is easy to track in New York Times stories through that stretch. An August 1881 item used the term of the day, “Albany beef,” to describe heavy demand for sturgeon meat: “In former years the catch of the sturgeon in the Hudson River was amply sufficient to supply all demands for the beef at low prices. Within the past few years, however, the fish have become scarce and shy.” The result, according to the story? Sturgeon were being imported to New York from as far away as the Kennebec River in Maine and Saint Johns River in Florida. A 1927 article reflected another pulse of overfishing with this title: “’Albany beef’ trade wanes as Hudson sturgeon dwindle.” Adding to the challenge, sturgeon, like shad and striped bass, face a kind of double jeopardy when they leave their spawning rivers and, as adults, cruise the Atlantic Coast. Uneven regulation was a factor. In my first New York Times story on collapsing Hudson River sturgeon populations, in 1996, commercial fishermen were irate that New Jersey was slow to stop sturgeon harvests. In the Hudson, the sign of trouble was a sharp drop in the abundance of the youngest fish, which would wander into shad nets every spring (and be released). One shad fisherman, Bob Gabrielson, visibly upset by this, told me how the armor-like knobbly “scutes” along the bodies of the youngest fish, not yet dulled by wear and tear, gleamed like hammered silver. “They’re the most beautiful thing in the world,” Gabrielson said. The species is listed federally as endangered in the New York region and three others and threatened in the Gulf of Maine. The discovery of a sturgeon so large in the river I’ve lived along, and reported on, since 1991 deeply excited me. This was particularly the case because, in 2010, I’d been out on the Hudson with Higgs and other state biologists doing the tagging study and videotaped the scene as they hauled a seven-foot, 120-pound male sturgeon onto their 21-foot boat to measure and inspect. I couldn’t imagine what a 14 footer would be like. To widen the view of this sonar signal, I turned first to John Cronin, an old friend who’s encountered the Hudson and its biological bounty in more ways than anyone I know. His four-decade-plus career along the Hudson has included commercial fishing for shad (a species now greatly depleted from the river), patrolling for pollution as the Hudson Riverkeeper and teaching environmental policy at nearby Pace University. He sees last summer’s sonar image less as a sign of hope than a reminder of just how profound the near-complete depletion of the Atlantic sturgeon has been—along with the loss of other once-keystone commercial species like the American shad. The loss is not just of fish but of the relationship communities have with their environment when fisheries are sustainable, Cronin said. He lamented how mismanagement of harvests, even when the science was clear, led to the final crash in the 1990s and then a ban on catches that will persist for many years, if not decades, to come. In an essay on his Earth Desk blog in 2013, centered on Native American lore around a “sturgeon moon,” Cronin captured the epic scale of the jolt this ancient species has felt in Earth’s Anthropocene age of human impacts. “Overharvesting of its meat and caviar, pollution, habitat alteration, power plant intakes—the list of insults that humans have invented trump every challenge thrown in the sturgeon’s path during 2,000,000 centuries of life on Earth,” he wrote. “Worth remembering the next time someone passes you the caviar….” Given the slow maturation and long lives of sturgeon, the losses have been akin to clearcutting an ancient forest, agreed John Waldman, a biology professor at the City University of New York and author of Running Silver: Restoring Atlantic Rivers and their Great Fish Migrations. What did he think of the sonar view of a fish as big as the biggest Atlantic sturgeon of any age? “This makes me think we often don’t really know that much about the status of sturgeon in any river,” Waldman said. He said the biggest sturgeon are big for a reason: “They’re almost totally cryptic and elusive and this is deep and murky water.” Sturgeon have been known to leap from the water on occasion, he said, “but it’s not like spotting the humpback whale that was in the lower Hudson a few years ago. They surface every few minutes.” “It’s a marvelous thing to see, even if just that one for now,” Waldman said 
Researchers in Finland found out that a lot more animals benefit from the presence of beavers than was previously known.
Abstract Beavers are ecosystem engineers which are capable to facilitate many groups of organisms. However, their facilitation of mammals has been little studied. We applied two methods, camera trapping and snow track survey to investigate the facilitation of a mammalian community by the ecosystem engineering of the American beaver (Castor canadensis) in a boreal setting. We found that both mammalian species richness (83% increase) and occurrence (12% increase) were significantly higher in beaver patches than in the controls. Of individual species, the moose (Alces alces) used beaver patches more during both the ice-free season and winter. The Eurasian otter (Lutra lutra), the pine marten (Martes martes) and the least weasel (Mustela nivalis) made more use of beaver sites during the winter. Our study highlights the role of ecosystem engineers in promoting species richness and abundance, especially in areas of relatively low productivity. Wetlands and their species have been in drastic decline during the past century, and promoting facilitative ecosystem engineering by beaver is feasible in habitat conservation or restoration. Beaver engineering may be especially valuable in landscapes artificially deficient in wetlands. https://www.sciencedirect.com/science/ar...9419302732  *This image is copyright of its original author Reintroducing beavers to help rivers manage climate change We're releasing beavers at Holnicote in Somerset and Valewood on the edge of the South Downs to improve flood management and support wildlife on our rivers. The beavers will help make areas of the river more resilient to climate change and the extremes of weather it will bring. The dams they create will hold water in dry periods, help to lessen flash-flooding downstream, reduce erosion and improve water quality. And more here on the work of riverlands 
The Tonle Sap (a great lake of Cambodia) is in trouble: https://www.latimes.com/world-nation/sto...reat-lakes
A woman sells mud carp from the lake in Kampong Luong; credit: Shashank Bengali  *This image is copyright of its original author
Bringing back beavers
Rivers are interesting things. They flow inexorably towards the sea, carrying what was once billions of raindrops, in huge web like networks fanning out across the landscape. They braid and meander, changing their course imperceptibly slowly. But how have rivers changed over time, and how did this affect the species living within them? Rivers In the Cambrian and early Ordovician periods (before around 450 million years ago), the continents were bare. Plants had not yet colonised the land, and without the weathering caused by their roots, there was no soil, only loose rock, gravel, and sand. Sedimentary records tell us that the rivers at this time were braided: split into smaller streams rapidly shifting across the riverbed, leaving behind characteristic alternating layers of fine grained and coarse grained sediments. Today, these kinds of rivers are found in the Arctic and high mountains - places where there is no vegetation to stabilise the riverbanks - as well as on beaches. When there is heavy rainfall, the whole channel is submerged and a new pattern of streams appears when the waters subside. When plants gained a foothold on the land, things began to change. Even the liverworts, diminutive slimy things which you might find on a damp boulder, had an impact on the structure of rivers. By weathering the top layer of rocks, they created clay. This cohesive mud resulted in more stable riverbanks, which slowed down the sideways migration of the channels. The clay also created soil, which allowed more sophisticated plants to colonise. Their root systems further stabilised the floodplains, forcing braided rivers into more defined and slowly meandering channels. Shifting mosaic The next big change came with the origin of trees, which by the Carboniferous period were covering vast areas of river deltas (and, as they fell into the anoxic swamp, forming much of the world’s coal). Rivers would have often become blocked by fallen trees and piles of debris. Blockages force the current sideways, carving out new channels into the floodplain. The result would have been a complex shifting mosaic of channels, oxbow lakes, and swamps in various stages of vegetation succession. It was in similar shallow swamps (although slightly earlier, in the Devonian period), that Acanthostega, thought to resemble the ancestor of terrestrial vertebrates, would have clambered through the waterweed and maybe occasionally wriggled onto land. Today, rivers of this kind can still be found in undisturbed parts of the Amazon. It’s not just plants that have influenced the changing patterns of rivers, but also animals, and none has had more impact than the beaver (apart from, of course, humans). Beavers The first beavers evolved in the Eocene period, around 45 million years ago. By building dams, beavers slow down the flow and promote the creation of new channels as the water spills out sideways. They create mosaics of habitats - ponds, riffles, marshes, wet woodland. The huge variation in physical environments - speed of flow, the depth and width of channels, size of sediment grains, water temperature - creates niches for many kinds of animals and plants. Whilst a beaver swamp may appear as one habitat when viewed from our perspective, at a finer scale there are myriad different microhabitats, a huge amount of variation crammed into a small space. We tend to overlook the effects that living organisms have on their physical world because most of the ecosystems around us have been “downgraded” as we have removed the important species - thus, in these cases it is mainly physical processes that determine how organisms survive. But there is now an increasing weight of evidence that the interaction works both ways: the earth shapes life, and life shapes the earth. Freestyle Beavers’ engineering work benefits many kinds of wildlife: ponds are perfect for frogs and fish larvae, riffles and gravel banks for dippers, swampy areas for water rails and moorhens, dead trees for woodpeckers and owls, and lush coppiced vegetation for songbirds. The fact that beaver habitat is ideal for so many species should not come as a surprise: beavers were present in our ecosystems for millions of years, so many wetland species may have actually evolved to live in beaver habitats. Through studying the effects that beavers have on streams, it has become clear that deeply incised river channels disconnected from their floodplain, which we perceive as the norm, are in fact a consequence of the removal of beavers, and other human impacts. Before we deforested and farmed the land and hunted beavers to extinction for their fur and scent glands, wetlands would have filled the bottoms of valleys, with snaking channels, ponds, wet meadows, and willow scrub. By bringing back the beaver, and allowing our rivers to freestyle through the landscape, we could revive these incredible ecosystems. Beaver engineered wetlands could fan out into every valley in an interconnected network, like arteries pumping life back into the landscape. So many other species could flourish in the habitats that beavers create: otters, water voles, marsh tits, spotted flycatchers, lesser spotted woodpeckers, water rails, egrets, lapwings, redshanks. Incredible species which we’ve almost forgotten could return - white tailed eagles, cranes, and even white storks, which last bred in the UK in 1416 but are just starting to make a comeback. Benefits Whilst large areas of wild land may always remain distant to most of us, beavers could create pockets of wildness nearby. The thrill I experienced when squelching through a beaver swamp in Devon was definitely the highlight of the past year. Experiencing these messy, exuberant living landscapes could rewild our own lives and so reconnect us with nature. This is especially important for younger generations, because people will not care about the living world unless they experience it at a young age. In the words of the lepidopterist Michael Pyle, “What is the extinction of a condor to a child who has never seen a wren?” A revival of beaver ecosystems would have wider environmental and economic benefits beyond increasing biodiversity and bringing wildness back into our lives. Their leaky dams hold back water in floods, and release it gradually in drought. By retaining water in the headwaters of catchments where the land is less valuable for farming, they could protect more productive arable land further downstream. As we experience more extreme weather events due to climate change, reintroducing beavers to our river systems could make a valuable contribution to reducing the damage to villages and towns. Lush swamps The lush swamps that beavers create have been shown to filter out fertiliser and pesticide runoff, and reduce the washing away of soil to the oceans - something which is currently visible from space whenever heavy rain falls. As vegetation builds up in the ponds it forms peat, and the carbon that was sequestered by the growing plants is locked away. We’ve spent thousands of years trashing the complex connections in our living world, and we’ve created ecosystems which are a mere shadow of their former selves. If there is one animal which we need in Britain right now, it has to be the beaver. The bang for your buck in terms of biodiversity and wider environmental gains is huge. Beavers transform their world so profoundly that they are like a fully automated tool for ecological restoration. We only have to release them and let them do the work. |
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