A dropline is a

commercial fishing Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

rig 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 carriage ...

consisting of a long

fishing line A fishing line is a 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 attachm ...

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 or indented, such that it can be used to grab onto, connect, or otherwise attach itself onto another object. In a number of uses, one e ...

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

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

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 M ...

. 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 the force acting on the object due to gravity. Some standard textbooks define weight as a Euclidean vector, vector quantity, the gravitational force acting on the object. Others define weigh ...

at the bottom of the line and are fixed to the water surface at least one

float Float may refer to: Arts and entertainment Music Albums * ''Float'' (Aesop Rock album), 2000 * ''Float'' (Flogging Molly album), 2008 * ''Float'' (Styles P album), 2013 Songs * "Float" (Tim and the Glory Boys song), 2022 * "Float", by Bush ...

at the top. They are usually not as long as

longline Long line or longline may refer to: *''Long Line'', an album by Peter Wolf *Long line (topology), or Alexandroff line, a topological space *Long line (telecommunications), a transmission line in a long-distance communications network *Longline fish ...

s and have fewer hooks. Droplines can be contrasted with

trotline A trotline is a heavy fishing line with shorter, baited branch lines commonly referred to as ''snoods'' suspending down at intervals using clips or swivels, with a hook at the free end of each snood. Trotlines are used in commercial angling an ...

s. 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 in ...

is that droplines are able to access areas that are otherwise natural fish refuges, such as

deep sea canyon A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to 5 km, from ...

s and

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

s.Australia's Sustainable Seafood Guide: Expanded Edition, published by AMCS The

Australian Marine Conservation Society The Australian Marine Conservation Society (AMCS) is an Australian environmental not-for-profit organisation. It was founded in 1965 as the Queensland Littoral Society before changing its name to the Australian Littoral Society and then finally in ...

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 or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only Extant taxon, extant species in the genus ''Orcinus'' and is recognizable by its black ...

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

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

Bering Sea The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Ameri ...

and

Prince William Sound Prince William Sound (Sugpiaq: ''Suungaaciq'') is a sound of 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 Tr ...

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