The science of sustainable seafood, explained

Will New Zealand fishermen lead the way from traditional seabird conservation measures to Hookpods?

Editor’s note: This post is the first part of a two-part series aimed to bring you behind the scenes of an emerging fishery technology. The first post comes from the perspective of a scientist—it explains the Hookpod technology and its conservation benefits. The second post is written by a fisherman who describes his experience with an emerging technology implemented in the 1990’s. He offers his thoughts on how the new Hookpod technology would impact and benefit fishermen. These two posts are an example of stakeholder perspectives that fishery managers consider when making decisions.

A hookpod baited with squid.
A hookpod baited with squid. Notice the barb stuck inside the pod - it will be released once it reaches a certain depth. | RSPB

Seabird bycatch in longline fisheries is a major conservation concern throughout the mid to high latitudes of the world’s oceans. It has been linked to declines and poor recovery of seabird populations and is the primary at-sea threat to albatross and petrels. Seabirds are attracted to fishing vessels to forage on discharged offal and used baits; they can become hooked and drown while foraging on baited hooks as they sink during longline deployment. Research published in 2011 estimated the annual mortality of seabirds attributable to world longline fisheries – demersal and pelagic – at 160,000 to 320,000 birds.

Among seabirds, albatrosses and petrels pose the most acute conservation concern due to a life history that is highly sensitive to adult mortality. Albatrosses are long lived, have a protracted pre-breeding life stage, and produce only one egg annually, or biennially. Although many albatrosses and petrels face threats on land at their breeding colonies, adult mortality at sea has the most influence on population trajectories and recovery. Albatrosses spend most of their lives foraging over vast expanses of the mid to high latitude oceans where they overlap with multiple fisheries. With 70% of 22 species threatened with extinction, albatrosses are the most threatened of any bird family. In response, several international agreements were established to characterize and stem mortality in longline fisheries including the United Nations Food and Agriculture Organization International Plan of Action for Reducing the Incidental Mortality of Seabirds in Longline Fisheries and the Agreement for the Conservation of Albatrosses and Petrels (ACAP). In addition to negative effects on seabird populations, seabird depredation of baits from longline hooks can increase fishing costs and compromise fishing efficiency. In some fisheries, seabird bycatch unchecked can lead to lost fishing access and negative perceptions of the fishery and reluctance throughout the supply chain to purchase the catch from high bycatch fisheries.

Seabird bycatch in longline fisheries is managed by requiring fishermen to use technical bycatch prevention measures and temporal and spatial limitations on fishing. Traditional best practice measures include deploying some combination of: a bird-scaring line (streamer lines or tori lines), using fast-sinking, weighted branchlines, and setting longlines at night. These measures are more difficult to apply in pelagic longline fisheries, because unlike bottom longlines, pelagic longlines are suspended from surface floats that can tangle with bird-scaring lines. Long (20 to 40 m) branchlines (monofilament line running from the longline to the hook) with weights positioned near the hook can pose a danger to crew as longlines are retrieved, while setting lines at night can compromise the catch rates of some species, limit fishing opportunities, and be unsafe.

New regulations in New Zealand, which came into force earlier this year, allow fishermen setting surface longlines (pelagic) the option to use hook-shielding devices like the Hookpod as a stand-alone alternative to traditional mitigation measures. This new legislation allows New Zealand to conform to revised conservation measures of the Western Central Pacific Fisheries Commission (WCPFC) that now include hook-shielding devices as an option to traditional measures to protect seabirds from mortality in pelagic longline fisheries. These regulatory changes also conform to revised best practice advice of ACAP. Through its Seabird Bycatch Working Group, ACAP evaluates and recommends best practice seabird bycatch avoidance measures for application to fisheries worldwide. It defines hook-shielding devices as those that “encase the point and barb of baited hooks to prevent seabird attacks during line setting until a prescribed depth is reached (a minimum of 10 meters), or until after a minimum period of immersion has occurred (a minimum of 10 minutes) that ensures that baited hooks are released beyond the foraging depth of most seabirds.” It is important to note that hook-shielding devices are designed specifically for application to the long (20 to 40 m) monofilament branchlines specific to pelagic longline fisheries, which target swordfish, tuna and tuna like species. Two hook-shielding devices were assessed as having met the specific performance criteria of ACAP: the Hookpod and the Smart Tuna Hook. At this time only the Hookpod is available commercially and meets New Zealand environmental standards.

Hookpods are available in two models: the Hookpod LED, which is heavier (60g) and includes a light emitting diode for fishermen who use lights (light sticks or electric) to attract fish, and the 48g Hookpod Mini without the LED for fishermen who prefer more flexibility with lighting. Both are a polycarbonate capsule that encases the barb of a baited hooks which is released via a pressure release system at a predetermined depth beyond the reach of seabirds.

Two recently published studies evaluated the performance of Hookpods in comparison to traditional measures. Research published in 2017 compared the performance of branchlines with Hookpod LEDs with a 10 m release depth (27,000 hooks) to branchlines with weights (31,000 hooks) in trials spread over four years, three countries and 18 trips. Only one bird was caught on the branchlines with Hookpods vs. 24 birds on control branchlines and fish catch rates were similar between treatments. Nine turtles were caught on lines with Hookpods and 22 on control lines. Research published in 2019 involved a smaller scale (roughly 5,000 hooks per treatment) experiment comparing the performance of the Hookpod Mini, (also with a 10 m release depth) to that of controls on two vessels in the New Zealand tuna fishery. Trials were extended (over 90,000 hooks) on one of the vessels to gauge operational issues. All treatments were set at night with a bird-scaring line deployed with one exception – the second vessel did not deploy a bird-scaring line in the Mini treatment. The first vessel had zero seabird bycatch in both treatments while the second vessel caught two birds – one in each treatment. Again, fish catch rates were similar between treatments. Operational trials done with streamer lines deployed for both treatments and with data logged by the skipper, yielded three birds caught in the Mini treatment vs. 13 birds caught in the control. Durability as measured by the replacement rate, which includes malfunctions, loss or damage to the Minis, was about one percent in both the experimental and operational trails, which is consistent with finding of the 2017 study of the Hookpod LED. The authors concluded that “…Hookpod-minis as a stand-alone mitigation measure are as effective, or more effective, than current bycatch mitigation measures including the combination of line weighting and tori lines.”

According to Becky Ingham, CEO of Hookpod Ltd, as of January 2020 the per unit cost of the 60g LED Hookpod ranges from £6.95 to £7.95 depending on quantity with a lead time of 24 weeks. The Mini sells for £3.95 to £4.95 with a lead time of 12 weeks. The designers of Hookpods are likely to continue to improve the product and lower costs as demand and experience builds. New Zealand, the seabird capital of the world, is the first country to provide hook-shielding devices as a regulatory option to prevent seabird bycatch in their tuna longline fisheries. The NZ Government is promoting the new mitigation option by providing a limited number of Hookpods free of charge to fishers and by developing plans to facilitate wide uptake by the fleet.

What is unique about the Hookpod hook-shielding devices is that they are a stand-alone method of seabird bycatch prevention that is robust to changing weather conditions without  the safety concerns of traditional measures. Plus, compliance can be gauged through port inspections – something that is not reliable for most traditional methods. They also may have the potential to reduce the bycatch rates of sea turtles by increasing the release depth of the pods, but this has yet to be proven. Although this news release by the makers of Hookpods suggests that their device has been “adopted” by New Zealand and WCPFC fisheries, it has yet to be determined how many fishermen will elect the Hookpod option. In many fisheries cost, durability concerns, and inertia could be barriers to widescale Hookpod adoption, especially in high seas tuna fisheries where vessels set up to 3,000 hooks per day and remain at sea for months. Many fishermen are already invested in traditional bycatch prevention gear and have incorporated that gear into their operations. However, in New Zealand, where seabird conservation in fisheries is firmly imbedded into the culture, Igor Debski, Principal Science Advisor Marine for the Department of Conservation, observes a level of frustration among fishermen regarding the safety and operational issues of traditional seabird avoidance measures. Igor believes this may well lead to Hookpods making the leap into fleet-wide adoption. Although traditional seabird bycatch reduction measures have their issues, they have been shown to be highly effective in multiple fisheries. For example, bird-scaring lines have been shown to be highly effective in many pelagic and demersal longline fisheries and in trawl fisheries around the world. A recent paper showed that bird-scaring lines, (the most commonly prescribed seabird bycatch prevention measure) alone reduced albatross bycatch rates by over 90% over 14 years in Alaskan demersal longline fisheries – one of the largest and most diverse longline fisheries in the world. Will New Zealand fishermen lead the way from traditional seabird conservation measures to Hookpods? What better place to do so than in the seabird capitol of the world.

Ed Melvin

Ed Melvin

Ed Melvin is an Affiliate Professor in the School of Aquatic and Fishery Science, University of Washington, and a member of the ACAP Seabird Bycatch Working Group.

Read Part 2 below:

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