Evaluation and implementation of discards policies under catch-based fisheries management regimes

• Main Author: Alzorriz Gamiz, Nekane
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Wageningen University 2019
• Subjects: Life Science; Canada; Faroe Islands; New Zealand; Norway; The Landing; Iceland
• Online Access: https://research.wur.nl/en/publications/evaluation-and-implementation-of-discards-policies-under-catch-ba; https://doi.org/10.18174/507129

This thesis brings a contribution to the debate, formally recognising fishers as an integral part of the ecosystem, by investigating the implications of applying a policy of limiting discards at sea in complex mixed fisheries that are managed under catch limits for the well-being of both the ecosystem and humans. Discard restrictions and discard management regimes have been implemented to different extents in a number of fisheries around the world (e.g., Chile, Norway, Faroe Islands, Iceland, New Zealand, Namibia, Canada, and the US). The implementation, monitoring and control of the landing obligation generates some new challenges. In particular, the focus of monitoring and control shifts from landing to activities at sea leading to potentially higher costs of enforcement as it might require, for successful implementation, full observer coverage or electronic video monitoring to validate a self-reporting system. In chapter 2, experiences from fisheries around the world show that choosing the right measures is not a simple process and therefore, management authorities need to simultaneously implement complementary measures which will support implementation and encourage compliance with discarding rules. The need to adapt the regulatory framework does not just concern enforcement systems. Other measures, including adaptations to the technical measure’s framework, also need to be considered. Improved selectivity of fishing gears remains a primary and important tool to avoid discards. In chapter 3 I studied the selective properties of a bottom trawl fitted with a 70 mm diamond mesh codend and a 100 mm top square mesh panel (SMP) in the commercial Basque bottom otter trawlers in the Bay of Biscay. Results suggested that a 100 mm SMP potentially enable undersized and immature individuals to escape through the meshes. However, the selectivity cruises demonstrated that in practice, the SMP was largely ineffective at releasing undersized and the release potential for the diamond mesh codend was found to be significantly ...