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gillnet Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...
, the tangle net, or tooth net, is a type of
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...
fishing net A fishing net is a net used for 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 ...
. Left in the water for no more than two days, and allowing
bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...
to be released alive, this net is considered to be less harmful that other nets. The tangle net is used in the
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
by commercial fishermen, as well as by the scientific community. When spent, these nets can be bundled, and left on the sea floor to collect smaller species. These bundles are known locally as lumen lumen nets. __TOC__


Description and technique

The tangle net originated in
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
, Canada, as a gear specifically developed for selective fisheries. Tangle nets have smaller mesh sizes than standard gillnets. They are designed to catch fish by their nose or jaw, enabling bycatch to be resuscitated and released unharmed. These nets are made with a very thin light
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...
rope, have a small mesh and are strung between two ropes, a top rope with floats, and a bottom rope with weights. Dropped to the bottom of the ocean, located and retrieved through the use of a guide line and buoy, these nets have allowed both fishermen and scientists to reach areas not previously accessible. Tangle nets are generally left on the bottom for no more than a day or two so that the fish and bycatch does not die and spoil.


Use in the Philippines

For the last two decades tangle nets have been set in deep water near steep underwater cliffs off many islands in the
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
by local fishermen in order to supplement their income through catching commercially valuable
mollusks Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is esti ...
. Scientists have used this technique in recent years to explore the deep water marine habitat. The rich species diversity of the
Philippine Islands The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
has been explored through the use of tangle nets which are able to obtain specimens from areas not reachable by traditional methods of using trawls and
dredges Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing da ...
. Through the placement of tangle nets 50 to 100 meters long, at depths from 100 meters to 400 meters, this cryptic marine habitat has been explored and many new and/or rare species of
gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
s and
crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
have been acquired. The success of deep set tangle nets was further exploited when
Philippe Bouchet Philippe Bouchet (born 1953) is a French biologist whose primary scientific fields of study are malacology (the study of molluscs) and taxonomy. He works at the Muséum National d'Histoire Naturelle in Paris. He is also a Commissioner of the ...
and Danilo Largo launched an expedition in 2004 to explore the Panglao area, known as the 2004 Panglao Marine Biodiversity Project.


Lumen lumen nets

When tangle nets are damaged beyond repair they are twisted and wrapped into long bundles, which the
Philippine The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
locals call lumen lumen nets. These long, sausage-like bundles are placed on the sea bottom along drop-offs in deep water with strong currents and left for several months at a time, which allows time for
veliger A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod ...
s to settle and larvae to grow. Lumen lumen nets have yielded many more species of marine animals, including many very small species of
micromollusk A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also ...
s.''Philippine Marine Mollusks, Volume 1''(2008) by Guido T. Poppe, at pp. 47-48, Published by Conchbooks, Hackenheim, Germany,


See also

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Drift net Drift netting is a fishing technique where nets, called drift nets, hang vertically in the water column without being anchored to the bottom. The nets are kept vertical in the water by floats attached to a rope along the top of the net and weig ...
*
Cast net A casting net, also called a throw net, is a net used for fishing. It is a circular net with small weights distributed around its edge. The net is cast or thrown by hand in such a manner that it spreads out while it's in the air before it sinks ...
*
Seine fishing Seine fishing (or seine-haul fishing; ) is a method of fishing that employs a surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be dep ...


References

{{fisheries and fishing Fishing industry Fishing techniques and methods Gastropods and humans Fishing nets