Anti-trawling device explained

Anti-trawling devices are a specific kind of artificial reef. Trawling is a controversial fishing practice which has attracted environmental, legal, and political objections. Anti-trawling devices have been invented, manufactured, and deployed to damage trawlers' nets and thus slow them down, force them to stop operating, or force them elsewhere. They are usually large concrete blocks with metal hooks or blades embedded in their tops. Anti-trawling devices are being used by environmental groups, fishermen, and sometimes even by governments.^{[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]}

As with artificial reefs in general,^[13] the actual effectiveness of anti-trawling reefs is understudied.^{[14] [15]} An Australian Government analysis anticipates very high costs and difficulty if they are removed. If they are removed, however, they expect:

• Increased fish abundance rather than decreased, because typically fishing increases around such devices to greater degree than the actual biological productivity does;
• Return and resurgence of finfish and other mobile organisms;
• Stabilization of prey numbers due to restored ecological balance due to the return of larger predators;
• Return of predators preventing "spill over" of predators and grazers into other areas;
• Restoration of appropriate movement and migration patterns.

They recommend changing permitting processes to account for the cost, and for whether removal is even feasible.^[16]

Notes and References

1. Web site: Creation of the Artificial Shellfish Reefs and Anti Trawling Devices . Marine Conservation Cambodia - Volunteer Internship in Marine Conservation and Research . 2016-10-14 . 2021-01-17 . 2021-01-17 . https://web.archive.org/web/20210117165610/https://marineconservationcambodia.org/blogs-news-and-history/mcc-news-updates/103-creation-of-the-artificial-shellfish-reefs-and-anti-trawling-devices . dead .
2. Tessier . A . Verdoit-Jarraya . M . Blouet . S . Dalias . N . Lenfant . P . A case study of artificial reefs as a potential tool for maintaining artisanal fisheries in the French Mediterranean Sea . . . 20 . 3 . 2014-05-07 . 1864-7782 . 10.3354/ab00563 . 255–272. free .
3. Iannibelli . M. . Musmarra . D. . Effects of anti-trawling artificial reefs on fish assemblages: The case of Salerno Bay (Mediterranean Sea) . . . 75 . 4 . 2008 . 1125-0003 . 10.1080/11250000802365290 . 385–394. 84091089 . free .
4. Position and monitoring of anti-trawling reefs in the Cape of Trafalgar (Gulf of Cadiz, SW Spain) . September 2000 . Bulletin of Marine Science . 67 . 2 . 761–77 . Juan J. Muñoz-Pérez . Jose M. Gutiérrez Mas . Jose M. Naranjo . Enrique Torres . Lorenzo Fages.
5. Serrano . Alberto . Rodríguez-Cabello . Cristina . Sánchez . Francisco . Velasco . Francisco . Olaso . Ignacio . Punzón . Antonio . Effects of anti-trawling artificial reefs on ecological indicators of inner shelf fish and invertebrate communities in the Cantabrian Sea (southern Bay of Biscay) . . Cambridge University Press (CUP) . 91 . 3 . 2010-06-02 . 0025-3154 . 10.1017/s0025315410000329 . 623–633. 86041772 .
6. Book: Ramos-EsplÁ . Alfonso A. . GuillÉn . Juan E. . Bayle . Just T. . SÁnchez-JÉrez . Pablo . Artificial Reefs in European Seas . Artificial Anti-trawling Reefs off Alicante, South-Eastern Iberian Peninsula: Evolution of Reef Block and Set Designs . . . 2000 . 978-0-7923-6144-2 . 10.1007/978-94-011-4215-1_12 . 195–218.
7. Web site: Anti-trawling block "NETTUNO" . Acquatecno . 2016-07-26 . 2021-01-17 .
8. Web site: Subtidal Benthic Invertebrate Conservation: Global Evidence for the Effects of Interventions. .
9. Web site: Install physical barriers to prevent trawling . Conservation Evidence . 2021-01-17.
10. Web site: Spain investigating claims that Gibraltar has further blocked bay . . 2013-08-23 . 2021-01-17.
11. Web site: Fishing Protection - OPEC Egypt . 2017-07-17 . 2021-01-17 .
12. Web site: Gibraltar Dispute: Spanish Fishermen in Reef Protest - Other Media news . . 2013-08-19 . 2021-01-17.
13. Macura . Biljana . Byström . Pär . Airoldi . Laura . Eriksson . Britas Klemens . Rudstam . Lars . Støttrup . Josianne G. . Impact of structural habitat modifications in coastal temperate systems on fish recruitment: a systematic review . . Collaboration for Environmental Evidence (BMC) . 8 . 1 . 2019-03-12 . 2047-2382 . 10.1186/s13750-019-0157-3 . 14 . 84831487 . Conclusions: This review revealed a very limited evidence base for how structural modifications and marine urban sprawl can affect fish recruitment. Thus, there is a substantial mismatch between stakeholder needs and research evidence. Further, the impact and ecological performance of artificial structures depend both on context and species. Clearly, there is a need for more research on the subject, especially on long-term consequences at larger spatial scales.. free . 2019EnvEv...8...14M . 11577/3401331 . free .
14. Baine . Mark . Artificial reefs: a review of their design, application, management and performance . . . 44 . 3–4 . 2001 . 0964-5691 . 10.1016/s0964-5691(01)00048-5 . 241–259 . 2001OCM....44..241B . Their use as a tool in coastal management has many general purposes including ... the prevention of trawling in Europe [4]. Artificial reef reviews do exist [5] although varying in their focus and objectivity. ... Number of papers ... Anti-trawling ... 5 ... These respective case studies refer to the use of vessels and concrete modules for the prevention of illegal trawling in the Mediterranean Sea ....
15. Airoldi . Laura . Beck . Michael W. . Firth . Louise B. . Bugnot . Ana B. . Steinberg . Peter D. . Dafforn . Katherine A. . Emerging Solutions to Return Nature to the Urban Ocean . . . 13 . 1 . 2021-01-03 . 1941-1405 . 10.1146/annurev-marine-032020-020015 . 445–477 . 32867567 . 2021ARMS...13..445A . 10026.1/16842 . 221402720 . 4.1.1.1. Artificial reefs. Artificial reefs are one of the earliest approaches to greening gray infrastructure ... providing multiple additional benefits. These benefits include blocking ... the use of trawling nets ... (Baine 2001). ... The effectiveness of artificial reefs is debated (Macura et al. 2019), and even when their stated primary objectives have been achieved, they come with negative impacts: They are expensive (Pioch & Doumenge 2010), and distortions or abuses of the concept have offered pretext for ocean dumping or for uncritical equation of any artificial structure to a reef (Macdonald 1994). However, the lessons learned have laid the foundations for new adaptive and biomimetic design concepts (Airoldi et al. 2005, Dafforn et al. 2015a, O'Shaughnessy et al. 2020), which aim to integrate some of the scopes of artificial reef design into structures built for other primary functions (Firth et al. 2014, Perkol-Finkel et al. 2012).. free .
16. Book: English . 2005 . Townsville, Qld, Australia . Technical Report No. 60 . 1–33 . D. . R. . Williams . Pears . Australian Government Cooperative Research Centres Program CRC Reef Research Centre . Potential effects of artificial reefs on the Great Barrier Reef: background paper . 1-876054-54-9 .