Smart Tuna Hook

Smart Tuna Hook - Ocean Smart
Copyright OceanSmart
Note: The similarly named 'Smart Hook' is a hook designed to deter sharks from approaching longline baits; see 'Magnetic, E+ metals and Electrical deterrents'.
 
The premise of the Smart Tuna Hook system is that it prevents hooking of seabirds and turtles during line setting by protecting a baited hook with a metal shield, which is held in place with a biodegradable pin. The pin dissolves once the hook is below the feeding depth of seabirds (25 m) and turtles (100 m). Once the pin dissolves, the shield is released and the baited hook is ready for fishing. The shield and the pin are both made of a metal alloy which dissolves, leaving no contaminants.
 
There are two components to the system - the hook and the shield. The Smart Tuna Hook is a modified tuna longline hook made to the size and pattern (including circle hooks) required by the fisher. It attaches to branch lines in the same way as regular tuna hooks and lasts just as long. The single-use Smart Hook Shield is applied manually (no applicator required) to the baited Smart Hook.
 

The Smart Tuna Hook has been assessed by ACAP (2023) and included in their list of best practice measures for mitigating bycatch in pelagic longline fisheries [1]. This is conditional upon the device meeting certain performance requirements, noted below:

‘Smart Tuna Hook’ – 40 g minimum weight that is positioned at the hook, encapsulating the barb and point of the hook during setting, and remains attached for a minimum period of 10 minutes after setting, when the hook is released.

Need for combination

This hook-shielding device has been designed as a stand-alone measure that does not need to be combined with other mitigation measures. However, it is useful to note that it integrates two performance components: i) protecting and ii) increasing the sink rate of the baited hooks to reduce the opportunities for seabirds to access them.
 
Effect on target catch
Baker and Candy (2014) found no detectable difference between catch rates for setting methods using regulator required mitigation and the Smart Hook for swordfish, yellow-fin tuna, big-eye tuna, southern Bluefin tuna, albacore tuna and other commercially targeted species [2]. This is in contrast to an early study that noted an increase in catch rates, though this was not statistically demonstrated [3].
Effect on Other Bycatch Species

Positive effect on reducing sea turtle bycatch, though more research needed. An Australian Fisheries Management Authority funded pilot study [3] evaluated the efficacy of the system in mitigating seabird and turtle bycatch in a longline fishery. The system was found to be very effective at preventing seabirds and turtles from being hooked when setting baited longlines, using a range of bait (fish and squid) and hook types.

Ease of Deployment and Safety

The shield is quickly and easily clipped by hand to the baited hook in the baiting process. Commercial trials demonstrated no increase in setting time and the system was perceived to improve both the ease of casting and bait retention (bait retained on the hook when casting and entering the water) [3].

The shield increases the sink rate of the baited hook without the need for lead swivels and is thus safer to retrieve.

Cost Information

Cost per vessel depends on the number of hooks vessels set each year. In 2017, Smart Hooks retailed for US $0.50 per hook shield and it was expected that if the device could be mass produced the cost could be lowered to US $0.20 per hook [2]. The use of recycled steel stands to lower the price further.

Compliance

A combination of port-based inspections and vessel based monitoring and surveillance (e.g. observer inspection of line setting operations; video surveillance; at-sea compliance checks) will be required to assess use and compliance.

Further Research

Conduct further field research to evaluate the relative contributions of the sink rates and hook protection components of hook-shielding devices in reducing seabird bycatch.

References
  1. ACAP. 2023. ACAP Review and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds. In: ACAP - Thirteenth Meeting of the Advisory Committee. Edinburg, UK.
  2. Parker 2017. Stocktake of measures for mitigating the incidental capture of seabirds in New Zealand commercial fisheries. Report to Southern Seabirds Solutions Trust by Parker Conservation. Dunedin.
  3. Jusseit, H. 2010. Testing seabird and turtle mitigation efficacy of the Smart Hook system in tuna long-line fisheries - Phase 1. AFMA Report 2008-805.
  4. Baker GB, Candy SG, Rollinson DP (2016) Efficacy of the ‘Smart Tuna Hook’ in reducing bycatch of seabirds in the South African Pelagic Longline Fishery. In: ACAP - Seventh Meeting of the Seabird Bycatch Working Group. ACAP, Serena, Chile, p ACAP-SBWG7-Inf07
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