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Tag: fish

Extinction: Freshwater fish in ‘catastrophic’ decline

Extinction: Freshwater fish in ‘catastrophic’ decline

Science
Getty ImagesA report has warned of a "catastrophic" decline in freshwater fish, with nearly a third threatened by extinction. Conservation groups said 80 species were known to have gone extinct, 16 in the last year alone.Millions of people rely on freshwater fish for food and as a source of income through angling and the pet trade.But numbers have plummeted due to pressures including pollution, unsustainable fishing, and the damming and draining of rivers and wetlands.The report said populations of migratory fish have fallen by three-quarters in the last 50 years.Over the same time period, populations of larger species, known as "megafish", have crashed by 94%. The decline of the 'disgusting' burbot' Hedge trimmer' fish facing global extinction'Hedge trimmer' fish facing global extinction'...
‘Hedge trimmer’ fish facing global extinction

‘Hedge trimmer’ fish facing global extinction

Science
Peter KyneThey are the most extraordinary of fish, resembling "hedge trimmers with fins".The sawfish, which is a kind of ray, is also among the most endangered of the fish living in the oceans.Once found along the coastlines of 90 countries, the animals are now presumed extinct in more than half of these, according to a new study. They are vanishing due to habitat loss and entanglement in fishing nets, experts have said.Their "saws", which evolved to sense and attack prey, have now become a liability, making them prone to being caught up in fishing gear."Through the plight of sawfish, we are documenting the first cases of a wide-ranging marine fish being driven to local extinction by overfishing," said Prof Nick Dulvy of Simon Fraser University (SFU) in British Columbia, Canada.'Time is ru...
Scientists shed light on how the blackest fish in the sea ‘disappear’

Scientists shed light on how the blackest fish in the sea ‘disappear’

Science
An ocean mystery - how the blackest fish in the deep sea are so extremely black - has been solved in a study that began with a very bad photograph. "I couldn't get a good shot - just fish silhouettes," said Dr Karen Osborn from the Smithsonian Institution. Her detailed study of the animal's "ultra-black" skin revealed that it traps light. While it makes the animals difficult to photograph, marine scientists say it provides the ultimate camouflage. The discovery, described in the journal Current Biology, could provide the basis for new ultra-black materials, such as coatings for the interior of telescopes or cameras. Several ultra-black species, according to the research, appear independently to ...
Whale sharks: Atomic tests solve age puzzle of world’s largest fish

Whale sharks: Atomic tests solve age puzzle of world’s largest fish

Science
Data from atomic bomb tests conducted during the Cold War have helped scientists accurately age the world's biggest fish.Whale sharks are large, slow moving and docile creatures that mainly inhabit tropical waters. They are long-lived but scientists have struggled to work out the exact ages of these endangered creatures. But using the world's radioactive legacy they now have a workable method that can help the species survival.Whale sharks are both the biggest fish and the biggest sharks in existence. Growing up to 18m in length, and weighing on average of about 20 tonnes, their distinctive white spotted colouration makes them easily recognisable. These filter feeders l...
Changes in oxygen, temperature could reshape deep sea fish communities

Changes in oxygen, temperature could reshape deep sea fish communities

Science
March 5 (UPI) -- The size and complexity of marine ecosystems make it difficult to predict the effects of climate change, especially on deep sea communities. But thanks to the efforts of a team of marine biologists and oceanographers, scientists are gaining a better understanding of the influence of oxygen and temperature on the density and diversity of deep sea fish populations. The study, led by scientists with the Scripps Institution of Oceanography at the University of California San Diego and the Monterey Bay Aquarium Research Institute, focused on demersal fish communities in the Gulf of California. Demersal fish are fish that live close to the seafloor. Their data and observations showed fish diversity dramatically declines in regions with very low levels of oxygen, concentrations...