Content deleted Content added
m Disambiguating links to Consensus (link changed to Consensus decision-making) using DisamAssist. |
Merline303 (talk | contribs) |
||
| (19 intermediate revisions by 14 users not shown) | |||
Line 5:
Trawling is done by a [[Fishing trawler|trawler]], which can be a small open boat with only {{convert|30|hp|abbr=on}} or a large factory trawler with {{convert|10000|hp|abbr=on}}. Bottom trawling can be carried out by one trawler or by two trawlers fishing cooperatively ([[pair trawling]]).
Global catch from bottom trawling has been estimated at over 30 million tonnes per year, an amount larger than any other fishing method.<ref>{{Cite journal|last1=Watson|first1=Reg A.|last2=Tidd|first2=A.|date=2018-07-01|title=Mapping nearly a century and a half of global marine fishing: 1869–2015|journal= [[Marine Policy]] |language=en|volume=93|pages=171–177|doi=10.1016/j.marpol.2018.04.023|s2cid=158305071 |issn=0308-597X|url=http://osf.io/mcvp5/}}</ref> Concerns about the environmental impacts of bottom trawling have led to changes in gear design, such as the addition of [[turtle excluder device]]s to reduce [[bycatch]], and limitations on locations where bottom trawling is allowed, such as [[marine protected area]]s.<ref>{{Cite web|url=http://www.seafoodwatch.org/ocean-issues/fishing-and-farming-methods|title=Fishing and Farming Methods from the Seafood Watch Program at the Monterey Bay Aquarium|website=www.seafoodwatch.org|language=en|access-date=2018-08-23}}</ref>
==History==
[[File:Pino Ladra 29.jpg|thumb|right|[[Viveiro]]|alt=Ship, [[Viveiro]]]]
An early reference to fishery conservation measures comes from a complaint about a form of trawling dating from the 14th century, during the reign of [[Edward III]].<ref>{{Cite journal |last=Jones |first=Peter |date=May 2018 |title=The long
<blockquote>
of so small a mesh, no manner of fish, however small, entering within it can pass out and is compelled to remain therein and be taken...by means of which instrument the fishermen aforesaid take so great abundance of small fish aforesaid, that they know not what to do with them, but feed and fatten the pigs with them, to the great damage of the whole commons of the kingdom, and the destruction of the fisheries in like places, for which they pray remedy.<ref>March, Page 33</ref><ref>{{cite web |last=Collins |first=J.W. |date=1887 |title=The Beam Trawl Fishery of Great Britain with Notes on Beam-Trawling in Other European Countries |url=https://spo.nmfs.noaa.gov/sites/default/files/pdf-content/fish-bull/fb7.60.pdf |access-date=17 March 2017 |publisher=[[Fishery Bulletin|Bulletin of the United States Fish Commission]] |page=292 |quote=100 MegaByte PDF}}</ref>
Line 32:
==Fishing gear==
{{externalimage
|
|width=160px
|image1=[https://www.afma.gov.au/methods-and-gear/trawling]
Line 61:
==Environmental damage==
{{see also|Environmental impact of fishing|environmental damage|Marine conservation}}
[[File:Lake Michigan Bottom Trawl Debris.webm|thumb|loop|Short clip of a bottom trawl of a lake and the large amounts of debris produced]]
Trawling gear produces acute impacts on biota and the physical substratum of the seafloor by disrupting the sediment column structure, overturning boulders, re-suspending sediments and imprinting deep scars on muddy bottoms.<ref>{{Cite news|last=Urbina|first=Ian|date=July 28, 2015|title=A Renegade Trawler, Hunted for 10,000 Miles by Vigilantes.|work=The New York Times|url=https://www.nytimes.com/2015/07/28/world/a-renegade-trawler-hunted-for-10000-miles-by-vigilantes.html|access-date=November 20, 2020}}</ref> Also, the repetitive passage of trawling gear over the same areas creates long-lasting, cumulative impacts that modify the cohesiveness and texture of sediments. It can be asserted nowadays that due to its recurrence, mobility and wide geographical extent, industrial trawling has become a major force driving seafloor change and affecting not only its physical integrity on short spatial scales but also imprinting measurable modifications to the geomorphology of entire continental margins.<ref name="researchgate.net">Oberle et al. (2018), [https://www.researchgate.net/publication/319112762_Submarine_Geomorphology_Bottom_Trawling_and_other_Fishing_Activities “Submarine Geomorphology: Bottom Trawling and other Fishing Activities”], Book: Submarine Geomorphology Chapter 25, Springer, doi: 10.1007/978-3-319-57852</ref>
Line 73 ⟶ 74:
|archive-date=2008-12-10
}}
</ref> A species of particular concern is the slow growing, deep water [[coral]] ''[[Lophelia pertusa]]''. This species is home to a diverse community of deep sea organisms, but is easily damaged by fishing gear. On 17 November 2004, the [[United Nations General Assembly]] urged nations to consider temporary bans on high seas bottom trawling.<ref>{{UN document |docid=A-59-PV.56 |body=General Assembly |type=Verbatim Report |session=59 |meeting=56 |page=4 |anchor=pg004-bk02 |date=17 November 2004 |speakername=Ms. Kimball | speakernation=International Union for the Conservation of Nature and Natural Resources |access-date=2009-05-09 }}</ref> A global analysis of the impacts of bottom trawling found that the impact on seabed [[Biota (biology)|biota]] was strongly dependent on the type of gear used, with otter trawls estimated as having the smallest impact and removing 6% of biota per pass while hydraulic dredges had the largest impact and removed 41% of biota per pass.<ref>{{Cite journal|last1=Hiddink|first1=Jan Geert|last2=Jennings|first2=Simon|last3=Sciberras|first3=Marija|last4=Szostek|first4=Claire L.|last5=Hughes|first5=Kathryn M.|last6=Ellis|first6=Nick|last7=Rijnsdorp|first7=Adriaan D.|last8=McConnaughey|first8=Robert A.|last9=Mazor|first9=Tessa|date=2017-07-14|title=Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance|journal= [[Proceedings of the National Academy of Sciences]] |volume=114|issue=31|language=en|pages=8301–8306|doi=10.1073/pnas.1618858114|issn=0027-8424|pmid=28716926|pmc=5547586|bibcode=2017PNAS..114.8301H |doi-access=free}}</ref> Other research found trawled canyon sediments contained 52 percent less organic matter than the undisturbed seafloor. There were 80 percent fewer sea worms in the trawled region and only half as much diversity of species in the trawled seafloor.<ref>{{Cite web | url=https://www.nationalgeographic.com/news/2014/5/140519-bottom-trawling-seafloor-oceans-damage-science/ | archive-url=https://web.archive.org/web/20200920075127/https://www.nationalgeographic.com/news/2014/5/140519-bottom-trawling-seafloor-oceans-damage-science/ | url-status=dead | archive-date=September 20, 2020 |title = In Brief: Deep-sea Trawling Has "Devastating" Impact, Study Finds| website=[[National Geographic Society]] |date = 2014-05-19}}</ref>
[[Image:Louisiana trawling landsat cropped.jpg|right|thumb|Satellite image of trawler mud trails off the Louisiana coast]]
===Resuspension and biogeochemistry===
Bottom trawling stirs up the sediment at the bottom of the sea. The [[suspended solids|suspended solid]] plumes can drift with the current for tens of kilometres from the source of the trawling, increasing sedimentation rates in deep environments <ref>{{Cite journal |doi = 10.1038/srep43332|title = Bottom-trawling along submarine canyons impacts deep sedimentary regimes|year = 2017|last1 = Paradis|first1 = Sarah|last2 = Puig|first2 = Pere|last3 = Masqué|first3 = Pere|last4 = Juan-Díaz|first4 = Xènia|last5 = Martín|first5 = Jacobo|last6 = Palanques|first6 = Albert|journal = Scientific Reports|volume = 7|page = 43332|pmid = 28233856|pmc = 5324136|bibcode = 2017NatSR...743332P}}</ref> Bottom trawling-induced resuspended sediment mass on the world's continental shelves
Bottom trawling can both resuspend and bury biologically recyclable organic material, changing the flow of nutrients and carbon through the food web and thereby alter geomorphological landscapes.<ref name="researchgate.net"/> Ocean sediments are the sink for many [[persistent organic pollutants]], usually [[lipophilic]] pollutants like [[Dichloro-Diphenyl-Trichloroethane|DDT]], [[Polychlorinated biphenyl|PCB]] and [[Polycyclic aromatic hydrocarbon|PAH]].{{citation needed|date=December 2020}} Bottom trawling mixes these pollutants into the [[plankton|plankton ecology]] where they can move back up the [[food chain]] and into our food supply.<ref>{{cite journal|doi=10.1016/j.envpol.2012.06.019|pmid=22842052|title=Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord|journal=Environmental Pollution|volume=170|pages=232–241|year=2012|last1=Bradshaw|first1=C.|last2=Tjensvoll|first2=I.|last3=Sköld|first3=M.|last4=Allan|first4=I.J.|last5=Molvaer|first5=J.|last6=Magnusson|first6=J.|last7=Naes|first7=K.|last8=Nilsson|first8=H.C.|bibcode=2012EPoll.170..232B }}</ref>
[[Phosphorus]] is often found in high concentration in soft shallow sediments.<ref>{{cite book|doi=10.1016/B0-08-043751-6/08153-6|chapter=The Global Phosphorus Cycle|title=Treatise on Geochemistry|pages=585–643|year=2003|last1=Ruttenberg|first1=K.C.|isbn=9780080437514}}</ref> Resuspending nutrient solids like these can introduce oxygen demand into the water column, and result in oxygen deficient [[Dead zone (ecology)|dead zone]]s.<ref>{{cite web |last1=US Department of Commerce |first1=National Oceanic and Atmospheric Administration |title=What is a dead zone? |url=https://oceanservice.noaa.gov/facts/deadzone.html#:~:text=%22Dead%20zone%22%20is%20a%20more%20common%20term%20for,as%20a%20result%20are%20often%20called%20%22dead%20zones.%22 |website=oceanservice.noaa.gov |access-date=16 October 2020 |language=EN-US}}</ref>
Even in areas where the bottom sediments are ancient, bottom trawling, by reintroducing the sediment into the water column, can create [[algae bloom|harmful algae blooms]].<ref>Giannakourou, A., Orlova, T.Y., Assimakopoulou, G., Pagou, K. (2005) ''Dinoflagellate cysts in recent marine sediments from Thermaikos Gulf, Greece.'' Continental Shelf Research 25, 2585-2596.
</ref><ref>Weaver, Dallas E (2007) [http://web.mac.com/deweaver/bottom_trawling/Links_to_Docs.html ''Remote Impacts of Bottom Trawling''] {{webarchive|url=https://web.archive.org/web/20090410185854/http://web.mac.com/deweaver/bottom_trawling/Links_to_Docs.html |date=2009-04-10 }}.</ref> More suspended solids are introduced into the oceans from bottom trawling than any other man-made source.<ref>{{cite journal |last1=Palanques |first1=A. |last2=Guillén |first2=J. |last3=Puig |first3=P. |title=Impact of bottom trawling on water turbidity and muddy sediment of an unfished continental shelf |journal=Limnology and Oceanography |date=July 2001 |volume=46 |issue=5 |pages=1100–1110 |doi=10.4319/lo.2001.46.5.1100 |bibcode=2001LimOc..46.1100P |doi-access=free |hdl=10261/244111 |hdl-access=free }}</ref>
Multiple large-scale reviews on bottom trawling have noted that there is a great need for further studies that properly examine the effects of nutrient and toxin remobilization as well as [[Carbon cycle|carbon cycling]],<ref>NRC (2002) (National Research Council) Effects of trawling and dredging on seafloor habitat. National Academies Press, Washington, DC</ref><ref>ICES (2006) International Council for the Exploration of the Sea (ICES): report of the WorkingGroup on Ecosystem Effects of Fishing Activities. ACE 05:1 179</ref> in order to better estimate [[greenhouse gas emissions]] and hence the impact on [[climate change]].<ref>{{Cite journal|date=2019-02-01|title=Quantifying and valuing carbon flows and stores in coastal and shelf ecosystems in the UK|journal=Ecosystem Services|language=en|volume=35|pages=67–76|doi=10.1016/j.ecoser.2018.10.013|issn=2212-0416|doi-access=free|last1=Luisetti|first1=Tiziana|last2=Turner|first2=R. Kerry|last3=Andrews|first3=Julian E.|last4=Jickells|first4=Timothy D.|last5=Kröger|first5=Silke|last6=Diesing|first6=Markus|last7=Paltriguera|first7=Lucille|last8=Johnson|first8=Martin T.|last9=Parker|first9=Eleanor R.|last10=Bakker|first10=Dorothee C.E.|last11=Weston|first11=Keith}}</ref>
Line 91 ⟶ 92:
[[File:Results of trawling.png|thumb|right|(A) The coral community and seabed on an untrawled seamount. (B) The exposed bedrock of a trawled seamount. Both are {{ Convert | 1,000–2,000 | m }} below the surface.]]
The [[Secretary General of the United Nations]] reported in 2006 that 95 percent of damage to [[seamount]] ecosystems worldwide is caused by [[deep sea]] bottom trawling.<ref>Report of the Secretary-General (2006) [https://www.un.org/Depts/los/general_assembly/documents/impact_of_fishing.pdf ''The Impacts of Fishing on Vulnerable Marine Ecosystems'']. [[United Nations]]. Retrieved on 10 August 2008</ref><ref>Reed JK, Koenig CC, Shepard AN, and Gilmore Jr RG (2007) {{usurped|1=[https://web.archive.org/web/20100104131308/http://archive.rubicon-foundation.org/7004 ''Long Term Monitoring of a Deep-water Coral Reef: Effects of Bottom Trawling'']}} Twenty-sixth annual Scientific Diving Symposium. Retrieved on 10 August 2008</ref> A study published in ''[[Current Biology]]'' suggests a cutoff of {{convert|600|m|ft}} is a point which ecological damage increases significantly.<ref>{{Cite news|title = Drawing the line|url = https://www.economist.com/news/science-and-technology/21663195-when-regulating-fishing-it-always-helps-have-data-drawing-line|newspaper = The Economist|access-date = 2015-09-18|issn = 0013-0613}}</ref>
== An estimated 370 million tonnes a year of carbon dioxide stored in seafloor sediment is released by bottom-trawling fishing.<ref>{{Cite news |last=McVeigh |first=Karen |date=2024-01-18 |title=Carbon released by bottom trawling 'too big to ignore', says study |url=https://www.theguardian.com/environment/2024/jan/18/carbon-released-by-bottom-trawling-too-big-to-ignore-says-study |access-date=2024-03-13 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> Most carbon released into the sea enters the atmosphere within a decade.<ref>{{Cite journal |last1=Atwood |first1=Trisha B. |last2=Romanou |first2=Anastasia |last3=DeVries |first3=Tim |last4=Lerner |first4=Paul E. |last5=Mayorga |first5=Juan S. |last6=Bradley |first6=Darcy |last7=Cabral |first7=Reniel B. |last8=Schmidt |first8=Gavin A. |last9=Sala |first9=Enric |date=2024 |title=Atmospheric CO2 emissions and ocean acidification from bottom-trawling |journal=Frontiers in Marine Science |volume=10 |doi=10.3389/fmars.2023.1125137 |doi-access=free |issn=2296-7745}}</ref> Banning bottom trawling in marine protected areas has been suggested.<ref>{{Cite web |date=2024-03-13 |title=Bottom trawling is huge source of carbon emissions, new study reveals |url=https://www.nationalgeographic.com/environment/article/climate-change-bottom-trawling-fishing |access-date=2024-03-13 |website=Environment |language=en}}</ref>
===Current restrictions===
Line 107 ⟶ 111:
*[[Venezuela]] was the first country to ban industrial trawling in its [[territorial waters]] and EEZ in 2009.<ref>{{Cite journal|last=Mendoza|first=Jeremy|title=Rise and fall of Venezuelan industrial and artisanal marine fisheries : 1950-2010 |journal=Fisheries Centre the University of British Columbia Working Paper Series|s2cid=141051731}}</ref><ref>{{Cite journal|last=Fischer|first=Johanne|date=2010|title=Review of the implementation of the international plan of action for the conservation and management of sharks|url=http://www.fao.org/tempref/FI/DOCUMENT/COFI/COFI_30/SBD8e.pdf|journal=FAO Fisheries and Aquaculture Circular|volume=1076}}</ref>
* [[Hong Kong]] passed legislation banning trawling on 18 May 2011 in an effort to restore the territory's devastated fish stocks and marine ecosystem. The ban came into effect on 31 December 2012. The government paid [[Hong Kong dollar|HK$]]1.72 billion to affected trawlers in a buyout scheme. Persons who contravene the ban can be fined or imprisoned under the Fisheries Protection Ordinance (Cap 171).<ref>{{cite web|title=Facts About the Trawling Ban in Hong Kong Waters|url=http://www.wwf.org.hk/en/whatwedo/conservation/marine/sos/abouttrawlban/|publisher=WWF Hong Kong|access-date=27 July 2016}}</ref><ref>{{cite web|title=AFCD officers intercept illegal trawler (with photo)|url=http://www.info.gov.hk/gia/general/201607/26/P2016072600978.htm|publisher=Hong Kong Government|date=26 July 2016}}</ref>
* [[Sri Lanka]] banned banning trawling in 2017, however, [[Exclusive economic zone of Sri Lanka|Indian fishermen regularly engage banning trawling]] in Sri Lankan waters.<ref>{{cite news |last1=Muiz |first1=Sarah |title=Sri Lankan seas still disturbed by Indian bottom trawling menace |url=https://www.dailymirror.lk/news-features/Sri-Lankan-seas-still-disturbed-by-Indian-bottom-trawling-menace/131-268447#:~:text=The%20industrial%20practice%20of%20bottom%20trawling%20by%20Indian,fishing%20practice%20which%20has%20been%20effective%20since%202017. |access-date=9 July 2024 |publisher=Daily Mirror |date=4 October 2023}}</ref>
===Lack of regulation===
| |||