FISHING NETS

 

ABOUT CONTACTS - FOUNDATION - HOME - A-Z INDEX

 

 

MIDWATER TRAWLIn midwater trawling a cone-shaped net is towed behind a single boat and spread by trawl doors (image), or it can be towed behind two boats (pair trawling) which act as the spreading device. Midwater trawling is relatively benign compared to the damage bottom trawling can inflict on the sea bottom.

 

Fishing nets are devices made from fibers woven in a grid-like structure. Some fishing nets are also called fish traps, for example fyke nets. Fishing nets are usually meshes formed by knotting a relatively thin thread. Early nets were woven from grasses, flaxes and other fibrous plant material. Later cotton was used. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and are still used.

 

 

 

NYLONThis is a nylon fishing net with float line attached to small plastic floats. Nylon is a very strong and durable engineering grade plastic that is also used to make bearings for machinery, printers and many more applications. It is not the plastic that is at falut, it is the way we are using it for fishing.

 

 

TRAWL NETA trawl is a large net, conical in shape, designed to be towed along the sea bottom. The trawl is pulled through the water by one or more boats, called trawlers or draggers. The activity of pulling the trawl through the water is called trawling or dragging. Bottom trawling results in a lot of bycatch and can damage the sea floor. A single pass along the seafloor can remove 5 to 25% of the seabed life.

A 2005 report of the UN Millennium Project, commissioned by UN Secretary-General Kofi Annan, recommended the elimination of bottom trawling on the high seas by 2006 to protect seamounts and other ecologically sensitive habitats. In mid October 2006, US President Bush joined other world leaders calling for a moratorium on deep-sea trawling.

 

 

 

PURSE SEINEThe purse seine net is widely used by commercial fishermen, is an evolution of the surround net, which in turn is an evolution of the seine net. A large net is used to surround fish, typically an entire fish school, on all sides. The bottom of the net is then closed by pulling a line arranged like a drawstring used to close the mouth of a purse. This completely traps the fish. There is a higher chance of bycatch using this fishing method.

 

NETS IN HISTORY

 

In Norse mythology the sea giantess Rán uses a fishing net to trap lost sailors. References to fishing nets can also be found in the New Testament. Jesus Christ was reputedly a master in the use of fishing nets. The tough, fibrous inner bark of the pawpaw was used by Native Americans and settlers in the Midwest for making ropes and fishing nets. The archaeological site at León Viejo (1524–1610) has fishing net artifacts including fragments of pottery used as weights for fishing nets.

Fishing nets have not evolved greatly, and many contemporary fishing nets would be recognized for what they are in Neolithic times. However, the fishing lines from which the nets are constructed have hugely evolved. Fossilised fragments of "probably two-ply laid rope of about 7 mm diameter" have been found in one of the caves at Lascaux, dated about 15,000 BC. Egyptian rope dates back to 4000 to 3500 BC and was generally made of water reed fibers. Other rope in antiquity was made from the fibers of date palms, flax, grass, papyrus, leather, or animal hair. Rope made of hemp fibres was in use in China from about 2800 BC.

Fishing nets have been used widely in the past, including by stone age societies. The oldest known fishing net is the net of Antrea, found with other fishing equipment in the Karelian town of Antrea. The net was made from willow, and dates back to 8300 BC. The remnants of another fishing net dates back to the late Mesolithic, and were found together with sinkers at the bottom of a former sea. Some of the oldest rock carvings at Alta (4200–500 BC) have mysterious images, including intricate patterns of horizontal and vertical lines sometimes explained as fishing nets. American Native Indians on the Columbia River wove seine nets from spruce root fibers or wild grass, again using stones as weights. For floats they used sticks made of cedar which moved in a way which frightened the fish and helped keep them together. With the help of large canoes, pre-European Maori deployed seine nets which could be over one thousand metres long. The nets were woven from green flax, with stone weights and light wood or gourd floats, and could require hundreds of men to haul.

Fishing nets are well documented in antiquity. They appear in Egyptian tomb paintings from 3000 BC.

 

 

PROBLEMFrom 2000 to 2012, the National Marine Fisheries Service reported an average of 11 large whales entangled in ghost nets every year along the US west coast. From 2002 to 2010, 870 nets were recovered in Washington (state) with over 32,000 marine animals trapped inside. Ghost gear is estimated to account for 10% of all marine litter.

According to the SeaDoc Society, each ghost net kills $20,000 worth of Dungeness crab over 10 years. The Virginia Institute of Marine Science calculated that ghost crab pots capture 1.25 million blue crabs each year in the Chesapeake Bay alone.

In May 2016, the Australian Fisheries Management Authority (AFMA) recovered 10 tonnes of abandoned nets within the Australian Exclusive Economic Zone and Torres Strait protected zone perimeters. One protected turtle was rescued.

 

Some commercial fisherman use gillnets that are suspended in the sea by flotation buoys, such as glass floats, along one edge. In this way they can form a vertical wall hundreds of metres long, where any fish within a certain size range can be caught. If not collected by fishermen these nets can continue to catch fish until the weight of the catch exceeds the buoyancy of the floats. The net then sinks, and the fish are devoured by bottom-dwelling crustaceans and other fish. Then the floats pull the net up again and the cycle continues. Given the high-quality synthetics that are used today, the destruction can continue for a long time.

 

 

BYCATCH

Fisheries often use large-scale nets that are indiscriminate and catch whatever comes along; sea turtle, dolphin, or shark. Bycatch is a large contributor to sea turtle deaths. Longline, trawl, and gillnet fishing are three types of fishing with the most sea turtle accidents. Deaths occur often because of drowning, where the sea turtle was ensnared and could not come up for air.

 

 

Sea turtle entangled in a fishing net

 

GHOST NETSA sea turtle is ensnared in this fishing net that has been abandoned by fishermen. Fishing nets are made of plastic that is very tough and float around killing marine wildlife and when they finally sink, cause more harm to ocean ecosystems. Ghost nets are fishing nets that have been left or lost in the ocean by fishermen. These nets, often nearly invisible in the dim light, can be left tangled on a rocky reef or drifting in the open sea. They can entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures, including the occasional human diver. Acting as designed, the nets restrict movement, causing starvation, laceration and infection, and suffocation in those that need to return to the surface to breathe.

 

National Geographic on plastic waste

 

LINKS & REFERENCE

 

http://www.whoi.edu/

http://news.nationalgeographic.com/news/2015/01/150109-oceans-plastic-sea-trash-science-marine-debris/

http://www.independent.co.uk/environment/plastic-waste-in-ocean-to-increase-tenfold-by-2020-10042613.html

https://en.wikipedia.org/wiki/Marine_debris

http://britishseafishing.co.uk/microplastics-and-ocean-pollution/

https://sustainabledevelopment.un.org/sdg14

http://wef.ch/plasticseconomy

 

 

 

 

 

 BIOMAGNIFICATION - BP DEEPWATER - CANCER - DDT - FISHING NETS - FUKUSHIMA - MICROBEADS - MICRO PLASTICS - OCEAN GYRES - OCEAN WASTE - PACKAGING - PCBS - PET - PLASTIC - POPS - SINGLE USE - WATER

 

 

Atlantic Ocean gyres, planet earth  Indian Ocean gyre, planet earth  Pacific Ocean gyres map on planet earth globe

 

GLOBAL WASTE PROBLEMThe above views of planet earth as global views show us the Atlantic, Indian and Pacific ocean gyres and estimates of plastic waste in (thousands) numbers of pieces of plastic waste per square kilometer of sea. The Pacific Ocean gyres are held to be the worst at the moment.

 

 

 

 This website is provided on a free basis as a public information service. copyright © Cleaner Oceans Foundation Ltd (COFL) (Company No: 4674774) August 2017. Solar Studios, BN271RF, United Kingdom. COFL is a charity without share capital.

 

 

 

 

OCEAN WASTE IS KILLING MARINE LIFE AND GETTING INTO THE FOOD CHAIN