Archive for March 5, 2009

Ghost Patrol – street art

Posted: March 5, 2009 in creativity



Ghost Patrol, one of Melbourne’s great street artists. He’s self taught, learning from friends and books. Hope people who discover his art will smile; thinks it would be nice to awaken them from their normal life and transport them to a more beautiful place. While liking travelling overseas and meeting & learning from other artists, he loves Melbourne because of its great community of street artists and illustrators and the opportunities the place offers to put on a show, publish something and grow creatively. He’s certainly versatile with his work ranging from street art to murals, illustrations, artworks, sculptures, Polaroids and more. Collaborates often with fabulous paste up artist, illustrator and partner Miso (unfortunately hasn’t got a website).

[Here I’ve just got some of his street art work; I’m planning to focus on some of his other stuff soon]







Sea lice photo: Watershed Watch

Honolulu, HI—Farming of fish in ocean cages is fundamentally harmful to wild fish, according to an essay in this week’s Conservation Biology.

Using basic physics, Professor Neil Frazer of the Department of Geology and Geophysics at the University of Hawaii at Manoa explains how farm fish cause nearby wild fish to decline. The foundation of his paper is that higher density of fish promotes infection, and infection lowers the fitness of the fish.

For wild fish, lowered fitness means more difficulty finding food and escaping predators, causing higher death rates. But farmed fish are not only fed, they are also protected from predators by their cage, so infected farm fish live on, shedding pathogen into the water. The higher levels of pathogen in the water cause the death rates of wild fish to rise.

The above paradigm explains recently documented declines of wild fish in areas with sea-cage farm fish.

Sea lice are an important example of disease transfer in ocean fish farming,” explains Frazer. “Sea lice are tiny crabs that attach to marine fishes, eating their skin and sometimes deeper tissue. Skin is important to fish because they need to keep their tissues less salty than the ocean. Also, when lice puncture the skin they create an entry point for other infections. So wild fish weakened by lice have more difficulty finding food and escaping predators.”

A female sea louse can produce over a thousand larvae during her life. Larvae drift in the ocean and a lucky few of them drift close enough to a fish to attach. Most larvae die without ever finding a fish. In a fish farm environment, a larva’s chance of finding a fish increases, so more larvae survive to become lice, and those lice put more larvae into the water. With more larvae in the water, more wild fish become infected and die as a result.

Larger numbers of lice are especially dire for salmon because juvenile salmon must transit coastal areas where salmon farms are located. Juvenile pink and chum salmon (Pacific species) suffer most because they spend much of their early life in coastal waters, and they are so small at ocean-entry that infection by even one or two lice can be fatal.

The calculations in the paper show that even if lice levels on farm fish are controlled by medication, local wild fish still decline. Also, there is a critical stocking level of farmed fish. If a sea-cage system is stocked above the critical level, local wild fish decline to extinction. Long story short — growing farm fish in sea cages can’t save wild fish, but it can easily destroy them.

[Thanks to Science Codex]

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Schooling prey fish surround a Sand Tiger Shark. [Credit: Gordon Stroupe]

Today Oceana released a new report, “Hungry Oceans: What Happens When the Prey is Gone?” that shows how overfishing, aquaculture feed and climate change are causing widespread malnutrition in predator fish, marine mammals and birds. As Oceana marine scientist Margot Stiles put it, “We have caught all the big fish and now we are going after their food.”

As populations of bigger fish have become overexploited and depleted, fisheries have emerged targeting prey fish — 7 of the top 10 fisheries in the world, in fact. In addition, aquaculture is increasingly the driver behind overfishing of prey fish, as salmon, tuna and other carnivorous farmed fish become the fastest growing seafood products in the world. Changing ocean temperatures and currents caused by climate change also make prey fish populations more vulnerable.

So who’s going hungry? To begin with, ocean predators such as whales, dolphins, seals, sea lions, and birds, who depend on squid, krill, and small fish to survive. In addition, many valuable commercial and recreational fisheries, specifically bluefin tuna, striped bass, Pacific salmon, and Pacific halibut are key species that depend on prey fish. Mediterranean bottlenose dolphins, for example, have declined significantly, in part because of overfishing of sardines and anchovy. Scientists working in the eastern Ionian Sea found 40 percent of bottlenose dolphins visibly emaciated due to starvation and other causes. The solution? More responsible management of fisheries.

The report ends with a proposed series of measures including a moratorium on new fisheries targeting prey species, conservative catch limits for existing fisheries, first priority for the needs of ocean predators, and stopping fishing for prey in predator breeding hotspots. “Hungry Oceans” coincides with the release today of the biennial State of the World Fisheries and Aquaculture report by the U.N. Food and Agriculture Organization (FAO). The FAO concludes that 80% of all marine fish stocks are currently fully exploited, overexploited, depleted, or recovering from depletion; including stocks of the 7 largest prey fisheries.

[Thanks to Oceana]

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