Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia

Poncet, Sally; Wolfaardt, A. C.; Black, Andrew; Browning, Sarah; Lawton, Kieran; Lee, Jennifer; Passfield, Ken; Strange, Georgina; Phillips, Richard A.

doi:10.1007/s00300-016-2057-0

Cited by 31 publications

(33 citation statements)

References 34 publications

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“…The colors corresponds to the current population trend: green-increasing; blue-stable; black-declining (ACAP, 2010;Wolfaardt, 2013;Poncet et al, 2017). These are minimum estimates of discard occurrence, including only the species that are not known to be naturally accessible to albatrosses (Table S1 in Supplementary Material).…”

Section: Fish Prey Diversitymentioning

confidence: 99%

“…Icefish and BBA are both krill predators, and in years of low krill availability, icefish are likely to provide a valuable alternate food source for albatrosses (Reid et al, 1996). The BBA population at South Georgia is declining, and although this appears to be due mainly to incidental mortality during the non-breeding period (Poncet et al, 2017), their breeding success is also lower than conspecifics in the Indian Ocean (Nevoux et al, 2010). During our study, the proportion of krill in the diet was low (Figure 2), and over the last 20 years of conventional sampling (in mid-late chick rearing), krill has contributed <20% of the diet in only 4 years, two of which were 2014 and 2015 (18.5 and 5.6%, respectively; British Antarctic Survey unpublished data).…”

Section: Competition With Fisheries and Reliance On Fishery Discardsmentioning

confidence: 99%

“…However, high breeding success and a population increase could also reflect greater discard availability. Conversely, at Macquarie Island, where there is no local fishery operating during the breeding season, breeding success of BBAs was lower and the population is stable (ACAP, 2010), and at South Georgia, where the icefish fishery is small and provides few discards, BBAs have the lowest breeding success and the population is declining (Poncet et al, 2017). Many factors can impact breeding success, and a snapshot of diet over 2 years is not definitive.…”

Section: Competition With Fisheries and Reliance On Fishery Discardsmentioning

confidence: 99%

“…Populations have experienced extensive declines which are strongly linked to incidental mortality in longline and trawl fisheries (Phillips et al, 2016). While the population at South Georgia is still declining (Poncet et al, 2017), numbers in the Falkland Islands and on islands off Chile are currently increasing (Wolfaardt, 2013;Robertson et al, 2014Robertson et al, , 2017. The increases in Chile have been attributed to a reduction in incidental seabird mortality due to faster sink rates of baited longline hooks associated with a change in fishing practices, and the use of birdscaring (streamer or tori) lines, making hooks less accessible to birds (Robertson et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…The inset shows the individual Chilean and Falkland Island colonies. Samples were collected from Albatross Islet, Chile (40-50 breeding pairs, population increasing); New Island (13,343 breeding pairs, population increasing) and Steeple Jason Island (183,135 pairs, population increasing), Falkland Islands; Bird Island, South Georgia (8,264 breeding pairs, population declining); Canyon des Sourcils Noirs, Iles Kerguelen (∼1,200 breeding pairs, population stable); and Macquarie Island (∼200 breeding pairs, population stable; ACAP, 2010;Wolfaardt, 2013;Robertson et al, 2014;Phillips et al, 2016;Poncet et al, 2017) TABLE 1 | The total samples at each site which contained food DNA derived from the 18S_SSU primer set and 16S_Fish primer set.…”

Section: Introductionmentioning

confidence: 99%

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DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

et al. 2017

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Almost all of the world's fisheries overlap spatially and temporally with foraging seabirds, with impacts that range from food supplementation (through scavenging behind vessels), to resource competition and incidental mortality. The nature and extent of interactions between seabirds and fisheries vary, as does the level and efficacy of management and mitigation. Seabird dietary studies provide information on prey diversity and often identify species that are also caught in fisheries, providing evidence of linkages which can be used to improve ecosystem based management of fisheries. However, species identification of fish can be difficult with conventional dietary techniques. The black-browed albatross (Thalassarche melanophris) has a circumpolar distribution and has suffered major population declines due primarily to incidental mortality in fisheries. We use DNA metabarcoding of black-browed albatross scats to investigate their fish prey during the breeding season at six sites across their range, over two seasons. We identify the spatial and temporal diversity of fish in their diets and overlaps with fisheries operating in adjacent waters. Across all sites, 51 fish species from 33 families were identified, with 23 species contributing >10% of the proportion of samples or sequences at any site. There was extensive geographic variation but little inter-annual variability in fish species consumed. Several fish species that are not easily accessible to albatross, but are commercially harvested or by-caught, were detected in the albatross diet during the breeding season. This was particularly evident at the Falkland Islands and Iles Kerguelen where higher fishery catch amounts (or discard amounts where known) corresponded to higher occurrence of these species in diet samples. This study indicates ongoing McInnes et al. Fishery Discards in Albatross Diets interactions with fisheries through consumption of fishery discards, increasing the risk of seabird mortality. Breeding success was higher at sites where fisheries discards were detected in the diet, highlighting the need to minimize discarding to reduce impacts on the ecosystem. DNA metabarcoding provides a valuable non-invasive tool for assessing the fish prey of seabirds across broad geographic ranges. This provides an avenue for fishery resource managers to assess compliance of fisheries with discard policies and the level of interaction with scavenging seabirds.

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Section: Fish Prey Diversitymentioning

confidence: 99%

Section: Competition With Fisheries and Reliance On Fishery Discardsmentioning

confidence: 99%

Section: Competition With Fisheries and Reliance On Fishery Discardsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

et al. 2017

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Foraging in a dynamic environment: Response of four sympatric sub‐Antarctic albatross species to interannual environmental variability

Carpenter-Kling

Reisinger

Orgeret

et al. 2020

Ecology and Evolution

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Seasonal and annual climate variations are linked to fluctuations in the abundance and distribution of resources, posing a significant challenge to animals that need to adjust their foraging behavior accordingly. Particularly during adverse conditions, and while energetically constrained when breeding, animals ideally need to be flexible in their foraging behavior. Such behavioral plasticity may separate “winners” from “losers” in light of rapid environmental changes due to climate change. Here, the foraging behavior of four sub‐Antarctic albatross species was investigated from 2015/16 to 2017/18, a period characterized by pronounced environmental variability. Over three breeding seasons on Marion Island, Prince Edward Archipelago, incubating wandering (WA, Diomedea exulans ; n = 45), grey‐headed (GHA, Thalassarche chrysostoma ; n = 26), sooty (SA, Phoebetria fusca ; n = 23), and light‐mantled (LMSA, P. palpebrata ; n = 22) albatrosses were tracked with GPS loggers. The response of birds to environmental variability was investigated by quantifying interannual changes in their foraging behavior along two axes: spatial distribution, using kernel density analysis, and foraging habitat preference, using generalized additive mixed models and Bayesian mixed models. All four species were shown to respond behaviorally to environmental variability, but with substantial differences in their foraging strategies. WA was most general in its habitat use defined by sea surface height, eddy kinetic energy, wind speed, ocean floor slope, and sea‐level anomaly, with individuals foraging in a range of habitats. In contrast, the three smaller albatrosses exploited two main foraging habitats, with habitat use varying between years. Generalist habitat use by WA and interannually variable use of habitats by GHA, SA, and LMSA would likely offer these species some resilience to predicted changes in climate such as warming seas and strengthening of westerly winds. However, future investigations need to consider other life‐history stages coupled with demographic studies, to better understand the link between behavioral plasticity and population responses.

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Long-term trends in albatross diets in relation to prey availability and breeding success

et al. 2020

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Diet analyses can reveal important changes in seabird foraging ecology and, by inference, resource availability and predator-prey dynamics within the wider marine ecosystem. Here, we analysed stomach contents of 1544 grey-headed albatross Thalassarche chrysostoma (GHA) and black-browed albatross T. melanophris (BBA) chicks from Bird Island, South Georgia. We describe dietary shifts (1996-2017), and link those to annual prey availability indices and breeding success. Annual variability in diet was high, and long-term trends in the main components were broadly similar in both albatrosses. Fish consumption (by mass) generally increased over time. Mackerel icefish Champsocephalus gunnari occurrence increased in GHA diets, but was unrelated to local densities derived from fisheries/research cruises. Cephalopod consumption declined until the early 2000s, then plateaued, and the occurrence of the ommastrephid squid Martialia hyadesi declined over time in both albatrosses. In BBAs, Antarctic krill Euphausia superba consumption decreased over time. Conversely, Antarctic krill consumption by GHAs increased until the early 2000s, decreased until the mid-2010s, and increased again in 2017. Antarctic krill consumption was unrelated to local densities based on acoustic surveys, and did not correlate with breeding success. Remotely sensed chlorophyll-a within core foraging areas showed a positive relationship with Antarctic krill in GHA diets, but a negative relationship with M. hyadesi occurrence in both albatross diets. Dietary shifts had consequences for GHA breeding success, which was negatively related to the importance of the cranchiid Galiteuthis glacialis and positively related to M. hyadesi importance. These results highlight the complex mechanisms linking prey availability, diet and breeding success in albatrosses.

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Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia

Cited by 31 publications

References 34 publications

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

DNA Metabarcoding as a Marine Conservation and Management Tool: A Circumpolar Examination of Fishery Discards in the Diet of Threatened Albatrosses

Foraging in a dynamic environment: Response of four sympatric sub‐Antarctic albatross species to interannual environmental variability

Long-term trends in albatross diets in relation to prey availability and breeding success

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