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Fishing

Fishing. most videos come from the following site http:// www.youtube.com/user/SeafoodWatch?feature=watch SaeafoodWatch , linked to the Monterey Bay aquarium overfishing. Pole-and-line.

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Fishing

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  1. Fishing • most videos come from the following site http://www.youtube.com/user/SeafoodWatch?feature=watch SaeafoodWatch, linked to the Monterey Bay aquarium • overfishing

  2. Pole-and-line • fishermen use a fishing pole and bait to target a variety of fish ranging from open-ocean swimmers, like tuna and mahimahi, to bottom-dwellers, like cod. • Pole/troll fishing methods have very low bycatch rates because fishermen catch one fish at a time and can release unwanted species when they're caught.

  3. bottom trawl • a type of fishing net that's pulled along the seafloor. • used catch shrimp and bottom-dwelling fish like halibut and sole. • However, in addition to these target fish, the nets also catch a variety of ocean life that's usually thrown back dead or dying. • Dragging heavy gear across the seabed can also damage sensitive seafloor habitat. • The harmful effects of bottom trawling on bottom-dwelling organisms and their habitat can be reduced by modifying the fishing gear or limiting trawling areas. • video • ..

  4. Dredge • large, metal-framed baskets that are dragged across the seafloor to collect shellfish like oysters, clams and scallops. • In order to lift the catch into the basket, metal teeth dig into the seafloor, which impact seafloor habitat and bottom-dwelling species. • Dredging also results in high levels of bycatch. • By restricting dredging areas, bycatch and damage to seafloor life can be reduced. • video

  5. Gillnetting • uses curtains of netting that are suspended by a system of floats and weights; • they can be anchored to the seafloor or allowed to float at the surface. • The netting is almost invisible to fish, so they swim right into it. • Gillnets are often used to catch sardines, salmon and cod, but can accidentally entangle and kill other animals, including sharks and sea turtles. • video

  6. Harpooning • traditional method for catching large fish—and it's still used today by skilled fishermen. • When a harpooner spots a fish, he thrusts or shoots a long aluminum or wooden harpoon into the animal and hauls it aboard. • Harpooners catch large, pelagic predators such as bluefin tuna and swordfish. • Harpooning is an environmentally responsible fishing method. • Bycatch of unwanted marine life is not a concern fishermen visually identify the species and size of the targeted fish before killing it

  7. Jigging • is another way of hand-catching fish. • A jig is a type of grapnel (or grappling hook) attached to a line, which is manually or mechanically jerked in the water to snag the fish. • Jigging often occurs at night, aided by light to attract the fish. • This targeted method of fishing has low levels of bycatch, making it an environmentally responsible fishing method.

  8. Longlining • a fishing line that can range from 1 to 50 miles long; • this line is strung with smaller lines of baited hooks, dangling at evenly spaced intervals. • can be set near the surface to catch pelagic fish like tuna and swordfish, or laid on the seafloor to catch deep-dwelling fish like cod and halibut. • Many lines, however, can hook sea turtles, sharks and seabirds that are also attracted to the bait. • By sinking longlines deeper or using different hooks, fishermen can reduce the bycatch problem. • video

  9. Midwater trawlers • vary in size—from small ships to large factory vessels. • Large industrial ships pull gigantic nets through the open ocean and can catch an entire school of fish—spanning the size of five football fields—at once. • These trawls don't impact the seafloor when used in the midwater zone. • Setting these trawls on schooling fish using streamer lines to scare away seabirds and avoiding areas with an abundance of marine mammals can help ensure low levels of bycatch in midwater trawl fisheries. • video

  10. Purse seining • creates a large wall of netting to encircle schools of fish. • Fishermen pull the bottom of the netting closed—like a drawstring purse—to herd fish into the center. • This method is used to catch schooling fish, such as sardines, or species that gather to spawn, such as squid. • There are several types of purse seines and, depending on which is used, some can catch other animals (such as when tuna seines are intentionally set on schools of dolphins). • Video • ..

  11. seine • a small-meshed net, suspended vertically in the water with floats and weights to enclose and concentrate fish. • Beach (or haul) seines are dragged over the bottom into shallow water or onto the beach, either by hand or with power winches. • . Used over soft sediment, like sand or mud, as the cloud of sediment helps herd the fish into the net.

  12. Traps and pots • are submerged wire or wood cages that attract fish with bait and hold them alive until fishermen return to haul in the catch. • Traps and pots are usually placed on the ocean bottom, often to catch lobsters, crabs, shrimp, sablefish and Pacific cod. • They generally have lower unintended catch and less seafloor impact than mobile gear like trawls • video

  13. Trolling • hook-and-line method of fishing tows lines behind or alongside a boat, catching species, such as salmon, mahimahi and albacore tuna, that follow a moving lure or bait. • Fishermen can quickly release unwanted catch from their hooks since lines are reeled in soon after a fish takes the bait. • This selective method of fishing results in very low bycatch levels.

  14. Over fishing with trawling

  15. Fish Farming (Aquaculture) • Aquaculture Issues: • Wild fish:Many of our favorite fish are themselves fish eaters. When we farm these carnivores, we need lots of wild fish to feed them. On average it takes over three pounds of wild fish to grow a pound of farmed salmon. Alternative feeds are being developed to reduce this dependence on wild fish. But the best solution may be farming shellfish and non-fish eaters like tilapia and catfish.Pollution & disease: When fish are farmed in open net pens, byproducts are released directly into the environment. This includes fish waste, uneaten food, disease, parasites, pesticides and antibiotics that can be harmful to the environment. In contrast, "closed" systems collect and manage these byproducts and have less impact. • Escapes: Each year, millions of fish escape from aquaculture operations, and their impacts aren't known. These escapees compete with native fish and, in the worst case, may interbreed with them—changing forever the gene pool of the native species. Reducing the use of open systems can help. • Habitat damage: Farm location is important. Rich coastal waters have been polluted by open net pen farms and hundreds of thousands of acres of coastal mangrove forests have been lost by conversion to shrimp ponds. Protecting important habitats and the species that rely on them for survival are key to sustaining the oceans.

  16. Hatchery • fish are bred and reared in nurseries, either for use in aquaculture or to be released and caught in wild-capture fisheries. • When released in large numbers, hatchery-raised fish can compete with wild populations for food. • concerns about genetically weaker hatchery fish interbreeding with and threatening the viability of wild populations. video Video

  17. Open net pens or cages • enclose fish such as salmon in offshore coastal areas or in freshwater lakes. • Net pens are considered a high-impact aquaculture method because waste from the fish passes freely into the surrounding environment, polluting wild habitat. • Farmed fish can also escape and compete with wild fish for natural resources or interbreed with wild fish of the same species, compromising the wild population. • Diseases and parasites can also spread to wild fish living near or swimming past net pens. • video

  18. Ponds • enclose fish in a coastal or inland body of fresh or salt water. • Shrimp, catfish and tilapia are commonly raised in this manner. • Wastewater can be contained and treated. • the discharge of untreated wastewater from the ponds can pollute the surrounding environment and contaminate groundwater. • the construction of shrimp ponds in mangrove forests has destroyed more than 3.7 million acres of coastal habitat important to fish, birds and humans. • video

  19. Raceways • allow farmers to divert water from a waterway, like a stream or well, so that it flows through channels containing fish. • In the U.S., farmers use raceways to raise rainbow trout. • If untreated, wastewater from the raceways can contaminate waterways and spread disease. • Video • video

  20. Many governments require strict regulation and monitoring of water quality; by treating wastewater these risks can be greatly minimized. • Escaped fish are another potential problem—they can compete with wild fish for natural resources and also interbreed with wild fish of the same species, potentially weakening the species genetically

  21. Recirculating systems • raise fish in tanks in which water is treated and recycled through the system. • any finfish species such as striped bass, salmon and sturgeon can be raised in recirculating systems. • Recirculating systems address many environmental concerns associated with fish farming—fish cannot escape, and wastewater is treated—but they are costly to operate and rely on electricity or other power sources.

  22. Submersible net pens (or cages) • designed for use in offshore aquaculture and can be used for a variety of fish species. • can be damaging to the local environment because water flows freely through the cages, carrying fish waste, uneaten food and chemicals into the surrounding water. • since the pens are open, there's the potential for farm diseases to transfer to wild fish populations.

  23. Shellfish culture • farmers grow shellfish on beaches or suspend them in water by ropes, plastic trays or mesh bags. • oysters, mussels and clams—are filter feeders and require only clean water to thrive. • Filter feeders can actually filter excess nutrients out of the water, but farming shellfish in high densities in areas with little current or tidal flow can lead to the accumulation of waste. • some shellfish culture has been responsible for the introduction of exotic species that can sometimes out-compete native species for natural resources.

  24. Shellfish culture • can be very sustainable. • Species such as oysters, mussels and clams are filter feeders that don't require additional feed and therefore don't impact wild fish stocks. • Farmers grow shellfish on beaches or suspend them in water by ropes, nets, trays or mesh bags. Habitat damage and impacts from effluent are generally minimal.

  25. Tuna Ranching • the process of capturing valuable juvenile species, usually carnivorous top predators, then growing them to harvest size on farms. • Highly profitable species such as bluefin tuna are caught at a relatively large size and "fattened" before harvest. • concerns about the high use of feed and waste from such farming operations, ranched species can't contribute to their natural ecosystems, threatening the overall health of those environments.

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