A dropline is a

commercial fishing Commercial fishing is the activity of catching fish and other seafood for Commerce, commercial Profit (economics), profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice ...

rig Rig or RIG may refer to: Objects and structures * Rig (fishing), an arrangement of items used for fishing * Drilling rig, a structure housing equipment used to drill or extract oil from underground * Rig (stage lighting) * rig, a horse-drawn c ...

consisting of a long

fishing line A fishing line is any flexible, high-tensile cord used in angling to tether and pull in fish, in conjunction with at least one hook. Fishing lines are usually pulled by and stored in a reel, but can also be retrieved by hand, with a fixed att ...

set vertically down into the water, with a series of baited

hook A hook is a tool consisting of a length of material, typically metal, that contains a portion that is curved/bent back or has a deeply grooved indentation, which serves to grab, latch or in any way attach itself onto another object. The hook's d ...

s attached to the ends of side-branching secondary lines called ''snoods''. Dropline fishing, or droplining, is a specialized

angling Angling (from Old English ''angol'', meaning "hook") is a fishing technique that uses a fish hook attached to a fishing line to tether individual fish in the mouth. The fishing line is usually manipulated with a fishing rod, although rodless te ...

technique Technique or techniques may refer to: Music * The Techniques, a Jamaican rocksteady vocal group of the 1960s * Technique (band), a British female synth pop band in the 1990s * ''Technique'' (album), by New Order, 1989 * ''Techniques'' (album), by ...

. Droplines may be set either down underwater trenches or just into the open water column. They have a

weight In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some sta ...

at the bottom of the line and are fixed to the water surface at least one float at the top. They are usually not as long as longlines and have fewer hooks. Droplines can be contrasted with trotlines. Whereas a dropline has a series of hooks suspended sideways off a vertical mainline, a trotline has a series of hooks suspended vertically off a horizontal mainline.

Conservation impacts

A concern for

marine conservation Marine conservation, also known as ocean conservation, is the protection and preservation of ecosystems in oceans and seas through planned management in order to prevent the over-exploitation of these marine resources. Marine conservation is i ...

is that droplines are able to access areas that are otherwise natural fish refuges, such as deep sea canyons and

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

s.Australia's Sustainable Seafood Guide: Expanded Edition, published by AMCS The Australian Marine Conservation Society rates dropline fishing as having a "moderate impact" on wildlife and a "low impact" on marine habitats. Droplines have the potential to interact with

orca The orca (''Orcinus orca''), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. The only extant species in the genus '' Orcinus'', it is recognizable by its black-and-white-patterned body. A cosmopol ...

s (killer whales). There is predation by orcas on commercial longline and dropline fish catches, including around

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

Bering Sea The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...

and

Prince William Sound Prince William Sound ( Sugpiaq: ''Suungaaciq'') is a sound off the Gulf of Alaska on the south coast of the U.S. state of Alaska. It is located on the east side of the Kenai Peninsula. Its largest port is Valdez, at the southern terminus of the ...

areas,Killer Whale (''Orcinus orca'') Depredation on Longline Catches of Sablefish (''Anoplopoma fimbria'') in Alaskan Waters. July 1988. Northwest and Alaska Fisheries Center, National Marine Fisheries Servic

/ref> causing significant financial loss to commercial fishers, and threat to orcas, which can become caught or entangled, exposed to ship strikes when moving or migrating, or suffer retaliation from fishers. Retaliation in response to predation on fish catches in previous decades has included shooting and harpooning of orcas.''Orcinus orca'': a Species Complex
, Whale and Dolphin Conservation Society. Accessed: 2007-02-13

References

External links

Australian Fisheries Management Authority {{fisheries and fishing Fishing techniques and methods Fishing industry