Patterns and trends in seabird bycatch in the pelagic longline fishery off South Africa

Rollinson, D. P.; Wanless, R. M.; Ryan, P G

doi:10.2989/1814232x.2017.1303396

Cited by 13 publications

(17 citation statements)

References 39 publications

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“…Our data show that adult white-chinned petrels from PEI overlap with pelagic longline fishing effort mainly off South Africa during the non-breeding/winter season. At this time of the year many white-chinned petrels visit South African waters (this study), which coincides with the period when pelagic longline fishing effort is at its highest in these waters (Rollinson et al 2017). The greatest levels of fisheries/petrel overlap occurred over the productive waters along the edge of the Agulhas Bank, where most seabirds are killed each year (Petersen et al 2009a, Rollinson et al 2017.…”

Section: Overlap With Fisheriessupporting

confidence: 51%

“…Differences in home range or foraging range were not investigated in other studies on white-chinned petrel movements (Weimerskirch et al 1999, Phillips et al 2006, Péron et al 2010a. A male bias in fisheries bycatch (particularly longlining) of white-chinned petrels has been found in several studies (Ryan & Boix-Hinzen 1999, Petersen et al 2009a, Rollinson et al 2017. This sex bias may be attributable to the larger size of males, which gives them a competitive advantage over the smaller females when foraging for bait and discards from fishing vessels, thus making them more likely to be caught as bycatch (Ryan & Boix-Hinzen 1999).…”

Section: Discussionmentioning

confidence: 98%

“…White-chinned petrels from South Georgia made wideranging trips during the pre-laying exodus (Phillips et al 2006), and our pre-breeding birds also dispersed more widely than during either incubation or early chick-rearing, with some birds reaching the South African coast. Almost all adult white-chinned petrels with enlarged gonads recorded as bycatch off South Africa were caught in the pre-breeding season (September-October; Rollinson et al 2017), with very small numbers caught during the incubation and early chick-rearing periods. The few birds with enlarged gonads caught during the incubation or early chick-rearing periods may have been failed breeders.…”

Section: Effect Of Breeding and Non-breeding Stagesmentioning

confidence: 99%

“…Large numbers of seabirds are killed each year by pelagic longline fisheries off South Africa, roughly two-thirds of which are white-chinned petrels (Petersen et al 2009a, Rollinson et al 2017. Prior to the implementation of individual vessel limits for seabird bycatch in the South African pelagic longline fishery (in 2008), up to 1000 whitechinned petrels were killed each year (Petersen et al 2009a), and in the 1990s an estimated 8000 white-chinned petrels were killed each year by the demersal longline fleet off South Africa (Barnes et al 1997).…”

Section: Overlap With Fisheriesmentioning

confidence: 99%

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Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean

et al. 2018

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White-chinned petrels Procellaria aequinoctialis L. are the most frequently recorded procellariiform species in the bycatch of Southern Hemisphere longline fisheries. Our study investigated the year-round movements of ten adult white-chinned petrels (seven breeders, three non-breeders/suspected pre-breeders) from Marion Island tracked with global location sensor (GLS) loggers for three years. Additionally, 20 global positioning system (GPS) tracks were obtained from breeding white-chinned petrels during incubation (n=9) and chick-rearing (n=11). All GLS-tagged birds remained, year-round, in the area between southern Africa and Antarctica, not making any major east/west movements. Three core areas (50% kernels) were utilized: around the Prince Edward Islands (PEI; incubation and early chick-rearing), c. 1000 km west of PEI (pre-breeding and early incubation) and around South Africa (non-breeding birds). The only area where 50% utilization kernels overlapped with intensive longline fishing effort was off the Agulhas Bank (non-breeding season). Our results confirm the lack of foraging overlap between the two subspecies; nominate birds (South Georgia/south-western Indian Ocean) utilize separate areas to P. a. steadi (New Zealand/sub-Antarctic islands), and thus should be treated as separate management units. Knowledge of the year-round movements of a vagile species, such as the white-chinned petrel, is important for its continued conservation.

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Section: Overlap With Fisheriessupporting

confidence: 51%

Section: Discussionmentioning

confidence: 98%

Section: Effect Of Breeding and Non-breeding Stagesmentioning

confidence: 99%

Section: Overlap With Fisheriesmentioning

confidence: 99%

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Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean

et al. 2018

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“…Over shelf edges, small-scale ARS were longer in duration and more sinuous, indicating more intense foraging behaviour compared to oceanic-tuna fisheries. These differences may be due to different operational practices between these fisheries, longer-lines (thus duration of line-setting and hauling), and different baits and offal [45].…”

Section: Discussionmentioning

confidence: 99%

How do seabirds modify their search behaviour when encountering fishing boats?

et al. 2019

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Seabirds are well known to be attracted by fishing boats to forage on offal and baits. We used recently developed loggers that record accurate GPS position and detect the presence of boats through their radar emissions to examine how albatrosses use Area Restricted Search (ARS) and if so, have specific ARS behaviours, when attending boats. As much as 78.5% of locations with a radar detection (contact with boat) during a trip occurred within ARS: 36.8% of all large-scale ARS (n = 212) and 14.7% of all small-scale ARS (n = 1476) were associated with the presence of a boat. During small-scale ARS, birds spent more time and had greater sinuosity during boat-associated ARS compared with other ARS that we considered natural. For, small-scale ARS associated with boats, those performed over shelves were longer in duration, had greater sinuosity, and birds spent more time sitting on water compared with oceanic ARS associated with boats. We also found that the proportion of small-scale ARS tend to be more frequently nested in larger-scale ARS was higher for birds associated with boats and that ARS behaviour differed between oceanic (tuna fisheries) and shelf-edge (mainly Patagonian toothfish fisheries) habitats. We suggest that, in seabird species attracted by boats, a significant amount of ARS behaviours are associated with boats, and that it is important to be able to separate ARS behaviours associated to boats from natural searching behaviours. Our study suggest that studying ARS characteristics should help attribute specific behaviours associated to the presence of boats and understand associated risks between fisheries.

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Variation in live-capture rates of albatrosses and petrels in fisheries, post-release survival and implications for management

Phillips

Wood

2020

Biological Conservation

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Patterns and trends in seabird bycatch in the pelagic longline fishery off South Africa

Cited by 13 publications

References 39 publications

Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean

Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean

How do seabirds modify their search behaviour when encountering fishing boats?

Variation in live-capture rates of albatrosses and petrels in fisheries, post-release survival and implications for management

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