Diving Ecology of Procellaria Petrels Highlights the Necessity of Combining Bird‐Scaring Lines, Weighted Branch Lines, and Night Setting in Pelagic Longline Fisheries

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 5:137-147 (2008) - DOI: https://doi.org/10.3354/esr00115 Seabird bycatch in the Brazilian pelagic longline fishery and a review of capture rates in the southwestern Atlantic Ocean Leandro Bugoni1, 2,*, Patricia L. Mancini1, Danielle S. Monteiro3, 4, Loretha Nascimento1, Tatiana S. Neves1 1Projeto Albatroz, Av. dos Bancários 76/22, Ponta da Praia, CEP 11030-300, Santos-SP, Brazil 2Institute of Biomedical and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK 3Núcleo de Educação e Monitoramento Ambiental – NEMA, R. Maria Araújo 450, Cassino, CEP 96207-480, Rio Grande-RS, Brazil 4Fundação Universidade Federal do Rio Grande, Laboratório de Elasmobrânquios e Aves Marinhas, C.P. 474, CEP 96201-900, Rio Grande-RS, Brazil *Email: l.bugoni.1@research.gla.ac.uk ABSTRACT: The southwestern Atlantic Ocean is an important foraging ground throughout the year for several albatross and petrel species. Longline fishing fleets in the region currently pose the main threat for this group of seabirds at sea, and conservation measures are urgently required. We present information on bycatch rates of seabirds in the Brazilian domestic pelagic longline fishery from 2001 to 2007, and review bycatch rates reported for the demersal and pelagic longline fisheries in the southwestern Atlantic Ocean. Overall seabird capture rate for the Brazilian pelagic longline fleet during 63 cruises (656 sets and 788446 hooks) was 0.229 birds per 1000 hooks, varying from 0 to 0.542 according to season. Capture rates were higher between June and November (cold season) and affected mainly the black-browed albatross Thalassarche melanophris (55% of birds captured), the white-chinned petrel Procellaria aequinoctialis, the spectacled petrel Procellaria conspicillata and the Atlantic yellow-nosed albatross Thalassarche chlororhynchos. Capture rates previously reported in the SW Atlantic varied from 0 to 5.03 birds per 1000 hooks, with those reports based on logbooks or fishermen interviews tending to underestimate capture rates, whereas those based on small numbers of hooks or short time periods tend to greatly overestimate rates in both pelagic and demersal longline fisheries. Previous studies have played an important role in delimiting the seabird bycatch problem, forming a baseline for mitigation actions and serving as a guide for improvements in data collection. However, data collected by onboard seabird-dedicated observers are more reliable, provide a greater range of information relating to bycatch, and form a baseline for more robust analysis and addressing further questions. The current study highlights the stochastic nature of seabird fatalities in longline fisheries and the need for extensive sampling to obtain realistic estimates of capture rates covering different years, seasons, vessels, and the range of fishing gear and practices. KEY WORDS: Albatrosses · Petrels · Longline · Incidental capture · Review · Brazil · Fisheries Full text in pdf format PreviousNextCite this article as: Bugoni L, Mancini PL, Monteiro DS, Nascimento L, Neves TS (2008) Seabird bycatch in the Brazilian pelagic longline fishery and a review of capture rates in the southwestern Atlantic Ocean. Endang Species Res 5:137-147. https://doi.org/10.3354/esr00115 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 5, No. 2-3. Online publication date: December 23, 2008 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2008 Inter-Research.

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 5:137-147 (2008) - DOI: https://doi.org/10.3354/esr00115 Seabird bycatch in the Brazilian pelagic longline fishery and a review of capture rates in the southwestern Atlantic Ocean Leandro Bugoni1, 2,*, Patricia L. Mancini1, Danielle S. Monteiro3, 4, Loretha Nascimento1, Tatiana S. Neves1 1Projeto Albatroz, Av. dos Bancários 76/22, Ponta da Praia, CEP 11030-300, Santos-SP, Brazil 2Institute of Biomedical and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK 3Núcleo de Educação e Monitoramento Ambiental – NEMA, R. Maria Araújo 450, Cassino, CEP 96207-480, Rio Grande-RS, Brazil 4Fundação Universidade Federal do Rio Grande, Laboratório de Elasmobrânquios e Aves Marinhas, C.P. 474, CEP 96201-900, Rio Grande-RS, Brazil *Email: l.bugoni.1@research.gla.ac.uk ABSTRACT: The southwestern Atlantic Ocean is an important foraging ground throughout the year for several albatross and petrel species. Longline fishing fleets in the region currently pose the main threat for this group of seabirds at sea, and conservation measures are urgently required. We present information on bycatch rates of seabirds in the Brazilian domestic pelagic longline fishery from 2001 to 2007, and review bycatch rates reported for the demersal and pelagic longline fisheries in the southwestern Atlantic Ocean. Overall seabird capture rate for the Brazilian pelagic longline fleet during 63 cruises (656 sets and 788446 hooks) was 0.229 birds per 1000 hooks, varying from 0 to 0.542 according to season. Capture rates were higher between June and November (cold season) and affected mainly the black-browed albatross Thalassarche melanophris (55% of birds captured), the white-chinned petrel Procellaria aequinoctialis, the spectacled petrel Procellaria conspicillata and the Atlantic yellow-nosed albatross Thalassarche chlororhynchos. Capture rates previously reported in the SW Atlantic varied from 0 to 5.03 birds per 1000 hooks, with those reports based on logbooks or fishermen interviews tending to underestimate capture rates, whereas those based on small numbers of hooks or short time periods tend to greatly overestimate rates in both pelagic and demersal longline fisheries. Previous studies have played an important role in delimiting the seabird bycatch problem, forming a baseline for mitigation actions and serving as a guide for improvements in data collection. However, data collected by onboard seabird-dedicated observers are more reliable, provide a greater range of information relating to bycatch, and form a baseline for more robust analysis and addressing further questions. The current study highlights the stochastic nature of seabird fatalities in longline fisheries and the need for extensive sampling to obtain realistic estimates of capture rates covering different years, seasons, vessels, and the range of fishing gear and practices. KEY WORDS: Albatrosses · Petrels · Longline · Incidental capture · Review · Brazil · Fisheries Full text in pdf format PreviousNextCite this article as: Bugoni L, Mancini PL, Monteiro DS, Nascimento L, Neves TS (2008) Seabird bycatch in the Brazilian pelagic longline fishery and a review of capture rates in the southwestern Atlantic Ocean. Endang Species Res 5:137-147. https://doi.org/10.3354/esr00115 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 5, No. 2-3. Online publication date: December 23, 2008 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2008 Inter-Research.

Growing concerns have been raised about incidental capture of seabirds in various fisheries. Here, studies testing measures to prevent seabird bycatch in longline, trawl and gillnet fisheries are reviewed in order to identify the most efficient mitigation methods. There is potential for considerable reduction in mortality rates in most longline fisheries because effective measures have been developed. However, there is no single solution as the efficiency of a measure is specific to each fishery. In demersal longline fisheries where northern fulmar is the dominant seabird captured, streamer lines have been proven to virtually eliminate mortality. In the fishery for Patagonian toothfish where interactions with albatrosses occur, night setting has resulted in considerable bycatch reductions. Night setting has also been proven to be efficient in pelagic fisheries, but this measure should be used in combination with streamer lines and weighted longlines in areas inhabited by nocturnal and diving birds. The main cause of mortality in trawl fisheries is collision with warp and netsonde cables, but studies are fragmentary. Interactions between cables and seabirds have been shown to be rare at times of no offal discharge, suggesting that a no-discharge policy would virtually eliminate mortality. Streamer lines have been proven to effectively reduce cable strikes under offal discharge. Measures to prevent birds from diving into the trawl net meshes have not been tested. Efficient mitigation methods that maintain target fish catch still have to be identified for gillnet fisheries. Future research in longline fisheries should fine-tune the most promising measures for each specific fishery. Effective measures identified for trawl fisheries need to be expanded to and tested in other areas where seabird interactions occur.

The black petrel (Procellaria parkinsoni) is recognised as the seabird species at greatest risk from commercial fishing activity within New Zealand fisheries waters. Despite the fact that valuable mitigation information could be obtained from such data, little is known about the diving ability of this species. Diving data were obtained from electronic time–depth recorders from 22 black petrels breeding on Great Barrier Island (Aotea), Hauraki Gulf, New Zealand, during the early chick rearing period from January-February in both 2013 and 2014. This paper presents the first information on the diving ability of black petrels. The deepest dive recorded was 34.3 m, but maximum dive depths varied considerably among individuals (range 0.8-34.3 m). The majority (86.8%) of all dives were < 5 m and black petrels rarely dived to depths of >10 m. The majority (92.7%) of dives were during the day and time of day had no major effect on dive depth. Only males dived at night, between 2300 and 0200 hours. This information could be used to improve mitigation measures for black petrel and other seabird bycatch in longline fisheries particularly in relation to recommended depths for unprotected hooks and line sink rates. To achieve the recommended minimum 10 m depth for unprotected hooks it has been shown that hooks have to be deployed at 6 knots with a 0.3 m/second line sink rate when using 100 m streamer lines. Adoption of these measures should further reduce black petrel bycatch in longline fisheries.

Although fisheries discards are recognized as a key food source for many seabirds, there have been few thorough assessments of their importance relative to natural prey, and of their influence on the trophic structure of pelagic seabird communities during the non-breeding period. Competition for resources in Procellariiformes appears to be reduced mainly by avoiding spatial overlap, which is supposed to influence diet composition. However, artificial food sources provided by fisheries might relax niche partitioning, increasing trophic niche overlap. Using bycaught birds from pelagic longline fisheries, we combined the conventional diet and stable isotope analyses to assess the importance of fishing discards in the diet of eight species of Procellariiformes. Both methods revealed the high contribution of trawl discards to the non-breeding diet of three neritic species and a moderate contribution in several other species; discards from pelagic and demersal longline fisheries were considerably less important. There was a clear contrast in diets of neritic vs. oceanic species, which are closely related taxonomically, but segregate at sea. Niche partitioning was less clear among neritic species. They showed an unexpectedly high level of diet overlap, presumably related to the large volume of trawl discards available. This is the first study combining the conventional diet and stable isotope analyses to quantify the importance of fishery discards for a community of non-breeding seabirds, and demonstrates how the super-abundance of supplementary food generates high levels of overlap in diets and allows the coexistence of species.

Understanding and addressing seabird bycatch in Alaska demersal longline fisheries

The effectiveness of tori‐lines combined with double‐weighted branch lines in reducing seabird bycatch was evaluated in a pelagic longline fishery. Seabird bait attack behaviour, bycatch number, and sinking rate of baited hooks were examined on double‐weighted and unweighted branch lines deployed on the same longline with a single tori‐line. Comparisons were conducted from July to October in 2011 during two cruises on a chartered longline vessel in the eastern South Pacific Ocean outside the Chilean and Peruvian exclusive economic zones. Cape petrels (Daption capense), white‐chinned petrels (Procellaria aequinoctialis) and Westland petrels (Procellaria westlandica) were abundant during line setting. There were 275 primary bait‐taking attacks by these species, but there were only eight primary attacks by albatrosses. Nevertheless, six albatrosses and six diving seabirds were incidentally caught as bycatch. Of the primary attacks by Cape petrels, white‐chinned petrels and Westland petrels, 153 led to secondary attacks. These results suggest that off Chile and Peru there is frequent secondary bycatch of albatrosses as a result of their stealing bait from Cape petrels and diving seabirds. Best‐fit models for the number of primary attacks and of bycatch included the weighted branch line; the use of weighted branch lines resulted in a lower number of primary attacks. Hooks on unweighted branch lines did not reach any of the benchmark depths (3, 5, and 10 m) within the aerial extent of the tori‐lines (the tori‐line remaining above the water surface), hooks on weighted branch lines reached 5 m depth within the aerial extent. These results suggest that, for the pelagic longline fishery off Chile and Peru, combining double‐weighted branch lines and tori‐lines reduces the bycatch more effectively than tori‐lines with unweighted branch lines. Copyright © 2014 John Wiley & Sons, Ltd.

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 39:1-8 (2019) - DOI: https://doi.org/10.3354/esr00953 ESR Special: Marine vertebrate bycatch: problems and solutions Hookpod-mini: a smaller potential solution to mitigate seabird bycatch in pelagic longline fisheries David Goad1,*, Igor Debski2, Joanne Potts3 1Vita Maris Limited, Papamoa, 3118, New Zealand 2Department of Conservation, Wellington, 6011, New Zealand 3The Analytical Edge Statistical Consulting, Tasmania, 7052, Australia *Corresponding author: goad.dave@gmail.com ABSTRACT: Hookpods are an emerging technology designed to reduce seabird bycatch in pelagic longline fisheries. Hookpod-minis were trialled in the New Zealand surface longline fishery in 2016-2017 during short-term experimental (20 longline sets) and longer-term operational (110 longline sets) trials. Two sets of experimental trials were conducted. The first compared snoods fitted with Hookpod-minis with a tori line to unweighted snoods with a tori line. The second compared snoods fitted with Hookpod-minis as a stand-alone mitigation measure to weighted snoods in combination with a tori line. All gear, across both trials, was set at night. Operational trials compared snoods fitted with Hookpod-minis and tori lines to standard mitigation requirements for unweighted gear and tori lines, with all gear set at night. Both sets of trials demonstrated that Hookpod-minis fit easily into fishing operations, do not reduce target species catch rate, and may reduce seabird bycatch to low levels. Our findings suggest 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. KEY WORDS: Mitigation · Pelagic longline · Seabird bycatch · Tori line Full text in pdf format NextCite this article as: Goad D, Debski I, Potts J (2019) Hookpod-mini: a smaller potential solution to mitigate seabird bycatch in pelagic longline fisheries. Endang Species Res 39:1-8. https://doi.org/10.3354/esr00953 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 39. Online publication date: May 02, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.

The incidental mortality of seabirds in longline fisheries is the major cause of the population declines threatening most albatross and large petrel species (LEWISON; CROWDER, 2003; ANDERSON et al., 2011). Currently there is a large and growing number of solutions for reducing seabird mortality on longlines. The combination of certain mitigation measures can greatly reduce seabird bycatch, although no single mitigation measure can reliably prevent seabird mortality. The combination of night setting, bird scaring lines and well-weighted branch lines are the best practice for the mitigation of seabird bycatch in pelagic longline fisheries (ACAP, 2014).The sink rate of baited hooks is arguably the major issue to be addressed to reduce seabird-longline interactions. Even when scaring lines are used, to make them effective the baited hooks must attain safe depths (i.e. deeper than the diving range of most petrel species) within the area protected by a scaring line. Many factors are known to affect the sink rate of baited hooks on pelagic longlines, such as the bait type (e.g. squid, mackerel, sardine, skipjack flash) and its state (e.g. dead or alive, frozen or thawed); the mainline tension during deployment; and line weight regimes (the use or not of leaded swivels, as well as their mass and distance from the hooks) (ANDERSON; MCARDLE, 2002; PETERSON et al., 2008, ROBERTSON et al., 2010; ROBERTSON et al., 2013).The best weighting regimes recommended are those that reach a depth of 10 m while under the protection of a scaring line with ~100 m aerial coverage (PETERSEN et al., 2008, MELVIN et al., 2009a). Experiments have indicated that ≥ 60 g placed no more than 3 m from the hooks is likely to achieve satisfactory sink rates under most operational conditions (MELVIN et al., 2009b; ROBERTSON et al., 2010; GIANUCA et al., 2011). Accordingly, among the best practices to reduce seabird mortality in pelagic longline fisheries recommended by the Agreement on the Conservation of Albatrosses and Petrels (ACAP, 2014) and the International Commission for the Conservation of Atlantic Tunas (ICCAT, 2011), is to use specific line-weighting regimes that ensure appropriate sink rates. The three recommended configurations are: weight greater than 45 g attached within 1 m of the hook or greater than 60 g attached within 3.5 m of the hook or greater than 98 g attached within 4 m of the hook. Positioning the weight farther than 4 m from the hook is not recommended.The use of chemical light sticks and more recently battery powered electric fishing lights (EFL), increases catch rates by attracting target species directly or by attracting their prey (BERKELEY et al., 1981; FREEMAN, 1989; ORTIZ; SCOTT, 2001; HAZIN et al., 2005). Despite the addition of this kind of device (usually ~2 m from the hooks) alters the surface/volume ratio of the terminal portion of the branch lines and potentially the sink rate of baited hooks, no investigation has yet been undertaken on this issue.EFL have recently been adopted by the southern Brazilian pelagic longline fleet, and their use and popularity are growing among fishermen and ship owners. Each EFL carries two AA batteries and, given its weight out of the water (~160 g), some fishermen argue that the use of this kind of device increases the sink rate of baited hooks, and using this untested premise as justification for not adopting the required line-weighting regimes.In the light of this scenario, the aim of the present

Marine megafauna exposed to fisheries bycatch belong to some of the most threatened taxonomic groups and include apex and mesopredators that contribute to ecosystem regulation. Fisheries bycatch is a major threat to the conservation of albatrosses, large petrels and other pelagic seabirds. Using data sourced from a fisheries electronic monitoring system, we assessed the effects of the time-of-day and relative depth of fishing on seabird and target species catch rates for a Pacific Ocean pelagic longline fishery that targets albacore tuna with an apparently high albatross bycatch rate. Using a Bayesian inference workflow with a spatially-explicit generalized additive mixed model for albacore tuna and generalized linear mixed regression models both for combined albatrosses and combined seabirds, we found that time-of-day and fishing depth did not significantly affect the target species catch rate while night-time deep setting had > 99% lower albatross and total seabird catch rates compared to both deep and shallow partial day-time sets. This provides the first evidence that night-time setting in combination with fishing deep reduces seabird catch risk and may be commercially viable in this and similar albacore tuna longline fisheries. Findings support evidence-informed interventions to reduce the mortality of threatened seabird bycatch species in pelagic longline fisheries.

Integrated weight longlines with paired streamer lines – Best practice to prevent seabird bycatch in demersal longline fisheries

Acoustics and photo-identification provide new insights on killer whale presence and movements when interacting with longline fisheries in South East Australia

Not much is known about the fleet level total seabird bycatch from pelagic longlines of United States vessels in the western North Atlantic or other fleets of the Atlantic or other oceans. Onboard observers generally only record seabird bycatch during line hauling. Seabirds are predominantly caught during the line setting stage, and, due to predation or mechanical action, those caught prior to the haul can drop off the hook and be lost to the onboard observer. We developed a model to gauge the size of this bycatch loss problem and provide a first approximation of its impact on estimates of total fleet bycatch. We started with a traditional loss-free bycatch model, which assumes that birds recorded were the only birds captured, and integrated into it two crucial components of the bycatch process: capture origin (set or haul) and bycatch loss of set-captures. We extracted count data on seabird bycatch loss and bycatch mortality from the literature on other longline fisheries and used these data to simulate potential total seabird bycatch in the western North Atlantic. Simulations revealed the shortcomings of both the traditional bycatch model and the current haul-only observer protocol, each of which contributed to biologically significant underestimation of total bycatch and estimation uncertainty. Based on our results, we recommend a loss-corrected modeling approach to provide a more accurate estimate of seabird mortalities in pelagic longline fisheries. Where possible, fishery-specific seabird bycatch loss rates need to be ascertained via specific set and haul observing protocols. But, even where fishery-specific estimates for a region are not available, the methodology developed here is applicable to other pelagic longline fisheries to approximate fleet-level loss-corrected bycatch.

Operational interactions between odontocetes (i.e., toothed whales) and longline gear are a global phenomenon that may threaten the conservation of odontocete populations and the economic viability of longline fisheries. This review attempts to define the issue, summarize the trends and geographical extent of its occurrence over the last half century, explore the potential impact on odontocetes and on fisheries, and describe potential acoustic and physical mitigation solutions.Reports of odontocete bycatch rates are highly variable (between 0.002 and 0.231 individuals killed per set) and at least 20 species may be involved. Information about marine mammal population size, migration patterns and life history characteristics are scarce, although at least one population may be in decline due to losses attributable to longline bycatch. Information about the financial impact of depredation on pelagic longline fisheries is also scarce, although estimates of daily fleet‐wide losses range between US$1,034 and US$8,495 (overall fleet income was not reported). Such biological and financial losses may be unsustainable.Recent developments in acoustic and physical mitigation technologies have yielded mixed results. Acoustic mitigation technologies have no moving parts, although require complex electronics. To date, they are insufficiently developed and their efficacy has been difficult to assess. Physical mitigation technologies generally require complex moving parts, although they are relatively simple to develop and assess. Further development and testing remains necessary before widespread implementation would be possible. Development of these approaches should be prioritized and a “toolbox” of various strategies and solutions should be compiled, because a single panacea to the problem is unlikely to emerge.

No effect from rare-earth metal deterrent on shark bycatch in a commercial pelagic longline trial