When is enough, enough? Quantifying trade-offs between information quality and sampling effort for fishing gear selectivity data

Abstract

There is general pressure throughout the world’s fisheries for the industry to have greater involvement not only in the development of fishing gears but also in the testing and documentation of their effect. In the European Union, the Common Fisheries Policy of 2013, together with the proposed reform of the technical measures regulation, highlights the need for greater flexibility in fisheries through increased stakeholder involvement. To achieve this flexibility, there is a need for additional fishing gears available to the fishermen. A way to facilitate this is to have the industry take part in the development and testing of fishing gears, as well as collect data on their performance. However, to have a successful industry-collected data programme, fishermen have to be able to collect data on the length of a portion of the catch. In this study, we determine how many individuals need to be measured to correctly evaluate the relative selective performance of a new gear compared to a standard gear. The evaluation was carried out by analysing catch ratio curves, their associated uncertainties, and the trade-offs between uncertainties and sampling effort. Results show that with relatively small sample sizes (500 to 1000 individuals) it is possible to correctly evaluate the performance of a gear for a given species. By having the industry develop and test their own gears, as well as being involved in the collection of data, the number of potential gear solutions available to address the different issues emerging in the fisheries is increased.

Effects of six codend meshes on the size selection of juvenile white croaker (Pennahia argentata) in demersal trawl fishery of the South China Sea

“…It has been demonstrated that the accuracy of selectivity studies for fishing gears would be affected by the number of fish caught and length measured in the sea trials [28,29]. The more fish is length measured, the less uncertainty will be obtained in the estimation of selective parameters.…”

The Aichi Biodiversity Targets: achievements for marine conservation and priorities beyond 2020

“…Current efforts to reduce negative fisheries impacts on a global scale include approaches such as bycatch reduction strategies ( Swimmer et al, 2011 ; O’Neill & Mutch, 2017 ; Veiga-Malta et al, 2018 ), bans on harvests of certain species ( Sherman et al, 2018 ), elimination of discards ( European Union, 2013 ), regulating exports related to non-sustainable fisheries ( Shiffman & Hueter, 2017 ), fishing regulatory closures for Vulnerable Marine Ecosystems (VME) in Areas Beyond National Jurisdiction (ABNJ) ( NEAFC, 2018 ), prohibition of destructive gear types for VMEs ( Auster et al, 2011 ), marine protected areas ( Hameed et al, 2017 ; Hastings, Gaines & Costello, 2017 ), and increased aquaculture production ( FAO, 2018 ; Froehlich, Gentry & Halpern, 2017 ). Implementation of conservation measures such as large-scale marine protected areas can pose challenges for nations that close off areas of their waters; however cross-jurisdictional management with transferable fishing rights has been proposed as a potentially viable market-based solution to promote transboundary cooperation in these situations ( Villaseñor-Derbez, Lynham & Costello, 2020 ).…”

Peer Review #3 of "The Aichi Biodiversity Targets: achievements for marine conservation and priorities beyond 2020 (v0.1)"

“…Current efforts to reduce negative fisheries impacts on a global scale include approaches such as bycatch reduction strategies (Swimmer et al, 2011;O'Neill & Mutch, 2017;Veiga-Malta et al, 2018), bans on harvests of certain species (Sherman et al, 2018), elimination of discards (European Union, 2013), regulating exports related to non-sustainable fisheries (Shiffman & Hueter, 2017), fishing regulatory closures for Vulnerable Marine Ecosystems (VME) in Areas Beyond National Jurisdiction (ABNJ) (NEAFC, 2018), prohibition of destructive gear types for VMEs (Auster et al, 2011), marine protected areas (Hameed et al 2017;Hastings et al 2017), and increased aquaculture production (FAO 2018;Froehlich et al 2017). Implementation of conservation measures such as large-scale marine protected areas can pose challenges for nations that close off areas of their waters; however cross-jurisdictional management with transferable fishing rights has been proposed as a potentially viable market-based solution to promote transboundary cooperation in these situations (Villaseñor-Derbez et al 2020).…”