Funded
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- Objectives
- Develop and test bycatch release devices in tuna purse seiners to improve post release survival, handling and release of sensitive key bycatch species, with particular emphasis on sharks
- Background
- Bycatch of Endangered, Threatened and Protected (ETP) species, especially elasmobranchs, are a concern in tropical tuna purse seine fisheries
- While the IATTC has resolutions promoting the application of best bycatch handling and releasing practices (e.g., for mobulids, sharks, turtles), there is a lack of clear guidelines for the fleet, and current release methods are quite rudimentary, often involving manual handling or basic self-made tools
- As part of fisheries improvement projects, several fishing organizations have implemented voluntary programs to improve bycatch handling and releasing practices.
- Associating and collaborating with experienced research institutions and fishing organizations would help explore, discuss and progress towards a reduction of bycatch mortality through the promotion of new tools that facilitate best handling and releasing practices
- Relevance for management
- Contributes to increase crew safety and survival of key sensitive bycatch species accidentally caught in tuna purse seiners
- Duration
- 24 months
- Workplan and status
- Coordinate the testing of a number of novel technological devices to release bycatch species in large tuna purse seiners
- These specific devices will be designed to achieve more efficient releases (e.g. faster, less handling stress, safer for the crew)
- The benefits of these devices will be assessed in terms of species survival using satellite tags and other biological indicators (e.g. lactate levels, vitality indicators, etc.)
- Collect device utilization data through IATTC observers and, scientific cruises with embarkment of AZTI/IATTC/ISSF scientists
- Use results of the project to inform conversations during skippers’ workshops
- Promote the utilization of the most efficient devices and methods in the region and, as appropriate, help shape recommendations
- External collaborators
- AZTI Foundation, the International Seafood Sustainability Foundation (ISSF) and OPAGAC
- Deliverables
- A report showing results from novel alternative bycatch release devices tested at sea in large tuna purse seiners
- Dissemination material, including documents and presentations for the IATTC Bycatch Working Group, the SAC and the tuna conference.
- Updated date: 01 May 2023
- Progress summary for the reporting period
- Jun-Sept 21: Discuss, decide, and build specific tools for large purse-seine vessels.
- Sept 21-Jan 22: Develop data collection forms and protocols as well as discuss and agree the sampling design.
- Jan 22-Apr 22: Finalize dedicated data collection forms and instructions and coordinate logistics for the first scientific cruise with a researcher from AZTI and an IATTC observer.
- Apr 22: The first scientific cruise had to be postponed at the last minute due to issues related to COVID-19.
- May 22: the first scientific cruise happened where 16 silky sharks were tagged.
Jun-Dec 22: information on shark handling and releasing practices was collected on two more trips. - May 23: a second scientific cruise has been organized to tag sharks and take blood samples to better understand the effect of stress in survivorship of the species.
- A third scientific cruise is expected in 2023 and project-specific observer-only data collection will also happen in additional trips.
- Challenges and key lessons learnt
- Some technological devices seem promising to improve both fishing crews’ safety and sharks post-release survival.
- New cutting-edge promising technologies (i.e., suction discs) are currently being explored as a potential technology to be used in purse seiners.
- Blood samples are needed to better understand the effect of stress on post-release survival of the species and develop size and fishing-operation-specific survival curves.
- A presentation at the BYC-10 meeting.
- A presentation at the EBWG-01 meeting.