Looming-eyes buoys fail to reduce seabird bycatch in the Icelandic lumpfish fishery: depth-based fishing restrictions are an alternative

Abstract

Bycatch in gillnets from lumpfish ( Cyclopterus lumpus ) fisheries is an important conservation issue in the north Atlantic, with up to 30 000 seabirds potentially killed each year. To date, no technical solutions exist to reduce the bycatch of seabirds in gillnet fisheries, but research on above-water bird deterrents as a form of bycatch mitigation has shown promising results. Here, we tested whether a floating device called ‘looming-eyes buoy’ (LEB) would consistently reduce the bycatch of seabirds in the Icelandic lumpfish fishery. We conducted 61 controlled trials with sets of normal gillnets and experimental nets equipped with LEBs. We compared both fish catch and bycatch between net types while accounting for exposure time, water depth and season, and found no effect of LEBs on both target lumpfish catch and bycatch. Our analysis indicated however a strong correlation between bycatch rates and fishing depths, suggesting that depth-based fishing restrictions could virtually eliminate the bycatch of seabirds in this fishery. We estimated that limiting fishing to waters more than 50 m deep could save between 5000 and 9300 seabirds every year, arrest the population decline of endangered black guillemots in Iceland, while having only a marginal effect on target fish catch.

Can depth-based restrictions avoid seabird bycatch while maintaining catch in the Icelandic lumpfish fishery? A reply to Kennedy & Sigurðsson (2024)

“…morhua), which shows that some seabird bycatch even occurs in waters greater than 50 m deep, which complements the data obtained in our study focussed only on the lumpfish fishery [3]. Unfortunately, Kennedy & Sigurðsson [4] did not present data on marine mammal bycatch, which peaked at intermediate depths in our study [3] and should be considered when exploring solutions to reduce non-target bycatch in the Icelandic lumpfish fishery [5].…”

“…In an attempt to develop solutions to this problem, we recently tested whether a bird-scaring device could reduce seabird bycatch in the Icelandic lumpfish (Cyclopterus lumpus) fishery, which kills an estimated 8000 seabirds annually [2]. This investigation showed that the device was ineffective, but that seabird and marine mammal bycatch could be virtually eliminated if (i) lumpfish fisheries were restricted to waters greater than 50 m deep, and (ii) the patterns we found in our study area would apply to other fishing areas around Iceland [3]. We acknowledged that further research was necessary to explore whether the fish catch and bycatch patterns we found in our study area were representative of all of Iceland and that socio-feconomic considerations were necessary before any fishery restrictions could be imposed.In a welcome contribution to work towards solutions for the bycatch problem in the Icelandic lumpfish fishery, Kennedy & Sigurðsson [4] now present novel data that shed further light on some of our assumptions.…”

Can depth-based restrictions avoid bird bycatch while maintaining catch rates in the Icelandic lumpfish fishery? A comment on Rouxel et al . (2023)

“…The bycatch of birds in bottom set gillnets in Iceland is recognized as an issue, with several technical solutions being proposed and trialled, but so far, without success [1,2]. Using data collected during an investigation on whether 'looming eyes' buoys could reduce bycatch in lumpfish (Cyclopterus lumpus) gillnets, Rouxel et al [1] proposed 'that limiting fishing to waters more than 50 m deep could save between 5000 and 9300 seabirds every year, arrest the population decline of endangered black guillemots (Cepphus grylle) in Iceland, while having only a marginal effect on target fish catch'. This is an interesting result and if this is indeed the case has potential to improve the environmental impact of this fishery.…”

“…This is an interesting result and if this is indeed the case has potential to improve the environmental impact of this fishery. The study by Rouxel et al [1] was based upon the catches of 84 fishing trips from 7 vessels, of which 21 fishing trips from 3 fishing vessels fished at a depth >50 m, with one boat accounting for 10 of these trips. The study took place in Húnaflói Bay, in northern Iceland (figure 1).…”

“…With fishers continuing to fish in spots where there are good catches and abandoning spots of poor catches. The data presented in Rouxel et al [1] and data from logbooks suggested that in certain areas, catch can be maintained at depths >50 m, but as Rouxel et al [1] acknowledged, there is likely to be greater competition for these spots under a depth restricted scenario and these areas may not be able to accommodate the fishers that have been displaced. The data from logbooks suggest that in areas A-C and G, catch would not be able to be maintained if fishing was restricted to depths >50 m. Given the substrate at depths >50 m in areas A-C, it seems unlikely that there are suitable spawning areas for lumpfish and therefore unlikely to be suitable spots to fish for lumpfish.…”