28 research outputs found
Light-level geolocators reveal spatial variations in interactions between northern fulmars and fisheries
Seabirdâfishery interactions are a common phenomenon of conservation concern. Here, we highlight how light-level geolocators provide promising opportunities to study these interactions. By examining raw light data, it is possible to detect encounters with artificial lights atnight, while conductivity data give insight on seabird behaviour during encounters. We used geolocator data from 336 northern fulmars Fulmarus glacialis tracked from 12 colonies in the North-East Atlantic and Barents Sea during the non-breeding season to (1) confirm that detections of artificial lights correspond to encounters with fishing vessels by comparing overlap between fishing effort and both the position of detections and the activity of birds during encounters, (2) assess spatial differences in the number of encounters among wintering areas and (3) test whethersome individuals forage around fishing vessels more often than others. Most (88.1%) of the track encountered artificial light at least once, with 9.5 ± 0.4 (SE) detections on average per 6 mo nonbreeding season. Encounters occurred more frequently where fishing effort was high, and birds from some colonies had higher probabilities of encountering lights at night. During encounters, fulmars spent more time foraging and less time resting, strongly suggesting that artificial lights reflect the activity of birds around fishing vessels. Inter-individual variability in the probability of encountering light was high (range: 0â68 encounters per 6 mo non-breeding season), meaning that some individuals were more often associated with fishing vessels than others, independently of their colony of origin. Our study highlights the potential of geolocators to study seabirdâfisheryinteractions at a large scale and a low cost.publishedVersio
Seabirds reveal mercury distribution across the North Atlantic
Author contributionsC.A. and J.F. designed research; C.A., B. Moe, A.T., S.D., V.S.B., B. Merkel, J.Ă
., and J.F. performed research; C.A., B. Moe, M.B.-F., A.T., S.D., V.S.B., B. Merkel, J.Ă
., J.L., C.P.-P., and J.F. analyzed data; C.A., B.M., V.S.B., and J.F. sample and data collection, data coordination and management, statistical methodology; H.S. sample and data contribution and Data coordination and management; D.G., M.B.-F., F. AmĂ©lineau, F. Angelier, T.A.-N., O.C., S.C.-D., J.D., K.E., K.E.E., A.E., G.W.G., M.G., S.A.H., H.H.H., M.K.J., Y. Kolbeinsson, Y. Krasnov, M.L., J.L., S.-H.L., B.O., A.P., C.P.-P., T.K.R., G.H.S., P.M.T., T.L.T., and P.B. sample and data contribution; A.T., P.F. and S.D. sample and data contribution and statistical methodology; J.Ă
. statistical methodology; J.F. supervision; and C.A., B. Moe, H.S., D.G., A.T., S.D., V.S.B., B. Merkel, J.Ă
., F. Amélineau, F. Angelier, T.A.-N., O.C., S.C.-D., J.D., K.E., K.E.E., A.E., P.F., G.W.G., M.G., S.A.H., H.H.H., Y. Kolbeinsson, Y. Krasnov, S.-H.L., B.O., A.P., T.K.R., G.H.S., P.M.T., T.L.L., P.B., and J.F. wrote the paper.Peer reviewe
Seabird sensitivity to Arctic environmental change
LâArctique se rĂ©chauffe deux fois plus vite que le reste du monde, entrainant des changements majeurs des Ă©cosystĂšmes marins. Par exemple, lâĂ©tendue de la banquise diminue, et la distribution des masses dâair change, modifiant les rĂ©gimes de vents et de prĂ©cipitations. ParallĂšlement Ă ces changements climatiques, lâArctique est soumise Ă une pollution anthropique croissante amenĂ©e par les circulations atmosphĂ©riques et ocĂ©aniques, et accentuĂ©e par le dĂ©veloppement des activitĂ©s humaines locales. Dans ce contexte, il est urgent de comprendre les impacts Ă©cologiques de ces modifications environnementales sur les espĂšces de cette rĂ©gion. Les mergules nains (Alle alle) sont les oiseaux marins les plus abondants de lâArctique, et des acteurs clĂ©s des rĂ©seaux trophiques cĂŽtiers. Bien que des travaux rĂ©cents aient suggĂ©rĂ© une forte rĂ©silience de ces organismes aux changements globaux, une Ă©tude approfondie permettant de comprendre de maniĂšre dĂ©taillĂ©e lâimpact de ces changements Ă©tait essentielle. Au cours de ce travail de thĂšse, nous avons donc utilisĂ© une approche pluridisciplinaire (Ă©cologie alimentaire, Ă©cotoxicologie, bioĂ©nergĂ©tique, Ă©cologie du dĂ©placement) menĂ©e Ă long terme afin de caractĂ©riser la sensibilitĂ© des mergules nains aux changements de leur environnement pendant la saison de reproduction (Ă©tĂ©) et en hiver. Nous avons pour cela Ă©tudiĂ© une population de mergules nains au Groenland Est. Nos rĂ©sultats montrent que les mergules sont fortement impactĂ©s par les changements en cours. Pendant la pĂ©riode de reproduction, leurs proies changent et leur effort de plongĂ©e augmente en lâabsence de banquise, mĂȘme sâils demeurent fidĂšles Ă leur zone de nourrissage sur le talus continental. Ceci tend Ă diminuer leur condition corporelle et celle de leur poussin, mais nâimpacte pas leur survie. En hiver, les mergules nains optimisent leur migration et leur distribution en fonction de la distribution de leurs proies et de leur paysage Ă©nergĂ©tique. Ainsi, nos modĂšles prĂ©dictifs indiquent quâun rĂ©chauffement de lâAtlantique nord pourrait ĂȘtre bĂ©nĂ©fique pour les populations en diminuant leurs besoins Ă©nergĂ©tiques. Enfin, nous avons trouvĂ© que les mergules nains consomment des microplastiques, et ce en les confondant avec leurs proies. Cette source de pollution supplĂ©mentaire pourrait augmenter avec la fonte de la banquise qui libĂšre des microplastiques jusque-lĂ stockĂ©s dans la glace. Ce travail souligne lâimportance des programmes Ă long terme pour lâĂ©tude des impacts des changements globaux.The Arctic is warming twice faster than the rest of the world, leading to major changes for marine ecosystems. For example, sea-ice extent is decreasing, and air mass distribution is changing, thus modifying wind and precipitation regimes. In parallel, the Arctic is subject to increasing anthropogenic pollution carried by atmospheric and oceanic circulation, and accentuated by the development of local human activities. In this context, there is an urgent need to understand the ecological impacts of these environmental modifications on the species of this region. Little auks (Alle alle) are the most abundant seabird in the Arctic, and key players of coastal food webs. Although recent works suggested a high resiliency of little auks to global changes, a comprehensive study was needed to understand in detail the impacts of these changes. Through this work, we used a multidisciplinary approach (diet ecology, ecotoxicology, bioenergetics, foraging ecology) on the long term to characterize little auk sensitivity to environmental changes during the breeding season (summer) and in winter. We therefore studied a little auk population in East Greenland. Our results show that little auks are indeed impacted by ongoing changes. During the breeding season, their prey change and their diving effort increase when there is no sea-ice, even if they remain faithful to their feeding grounds on the continental slope. This tends to decrease their body condition and that of their chick, but does not impact their survival. In winter, little auks optimize their migration and their distribution according to the distribution of their prey and their energetic landscape. Therefore, our predictive models indicate that a warming of the North Atlantic could be benefic for little auk populations, by reducing their energetic needs. Finally, we found that little auks ingest microplastics, by confusing them with their prey. This additional source of pollution could increase with sea-ice loss that release microplastics stocked in the ice. This work underlines the importance of long term monitoring programs for the study of global change impacts
SensibilitĂ© dâun oiseau marin arctique aux changements environnementaux
The Arctic is warming twice faster than the rest of the world, leading to major changes for marine ecosystems. For example, sea-ice extent is decreasing, and air mass distribution is changing, thus modifying wind and precipitation regimes. In parallel, the Arctic is subject to increasing anthropogenic pollution carried by atmospheric and oceanic circulation, and accentuated by the development of local human activities. In this context, there is an urgent need to understand the ecological impacts of these environmental modifications on the species of this region. Little auks (Alle alle) are the most abundant seabird in the Arctic, and key players of coastal food webs. Although recent works suggested a high resiliency of little auks to global changes, a comprehensive study was needed to understand in detail the impacts of these changes. Through this work, we used a multidisciplinary approach (diet ecology, ecotoxicology, bioenergetics, foraging ecology) on the long term to characterize little auk sensitivity to environmental changes during the breeding season (summer) and in winter. We therefore studied a little auk population in East Greenland. Our results show that little auks are indeed impacted by ongoing changes. During the breeding season, their prey change and their diving effort increase when there is no sea-ice, even if they remain faithful to their feeding grounds on the continental slope. This tends to decrease their body condition and that of their chick, but does not impact their survival. In winter, little auks optimize their migration and their distribution according to the distribution of their prey and their energetic landscape. Therefore, our predictive models indicate that a warming of the North Atlantic could be benefic for little auk populations, by reducing their energetic needs. Finally, we found that little auks ingest microplastics, by confusing them with their prey. This additional source of pollution could increase with sea-ice loss that release microplastics stocked in the ice. This work underlines the importance of long term monitoring programs for the study of global change impacts.LâArctique se rĂ©chauffe deux fois plus vite que le reste du monde, entrainant des changements majeurs des Ă©cosystĂšmes marins. Par exemple, lâĂ©tendue de la banquise diminue, et la distribution des masses dâair change, modifiant les rĂ©gimes de vents et de prĂ©cipitations. ParallĂšlement Ă ces changements climatiques, lâArctique est soumise Ă une pollution anthropique croissante amenĂ©e par les circulations atmosphĂ©riques et ocĂ©aniques, et accentuĂ©e par le dĂ©veloppement des activitĂ©s humaines locales. Dans ce contexte, il est urgent de comprendre les impacts Ă©cologiques de ces modifications environnementales sur les espĂšces de cette rĂ©gion. Les mergules nains (Alle alle) sont les oiseaux marins les plus abondants de lâArctique, et des acteurs clĂ©s des rĂ©seaux trophiques cĂŽtiers. Bien que des travaux rĂ©cents aient suggĂ©rĂ© une forte rĂ©silience de ces organismes aux changements globaux, une Ă©tude approfondie permettant de comprendre de maniĂšre dĂ©taillĂ©e lâimpact de ces changements Ă©tait essentielle. Au cours de ce travail de thĂšse, nous avons donc utilisĂ© une approche pluridisciplinaire (Ă©cologie alimentaire, Ă©cotoxicologie, bioĂ©nergĂ©tique, Ă©cologie du dĂ©placement) menĂ©e Ă long terme afin de caractĂ©riser la sensibilitĂ© des mergules nains aux changements de leur environnement pendant la saison de reproduction (Ă©tĂ©) et en hiver. Nous avons pour cela Ă©tudiĂ© une population de mergules nains au Groenland Est. Nos rĂ©sultats montrent que les mergules sont fortement impactĂ©s par les changements en cours. Pendant la pĂ©riode de reproduction, leurs proies changent et leur effort de plongĂ©e augmente en lâabsence de banquise, mĂȘme sâils demeurent fidĂšles Ă leur zone de nourrissage sur le talus continental. Ceci tend Ă diminuer leur condition corporelle et celle de leur poussin, mais nâimpacte pas leur survie. En hiver, les mergules nains optimisent leur migration et leur distribution en fonction de la distribution de leurs proies et de leur paysage Ă©nergĂ©tique. Ainsi, nos modĂšles prĂ©dictifs indiquent quâun rĂ©chauffement de lâAtlantique nord pourrait ĂȘtre bĂ©nĂ©fique pour les populations en diminuant leurs besoins Ă©nergĂ©tiques. Enfin, nous avons trouvĂ© que les mergules nains consomment des microplastiques, et ce en les confondant avec leurs proies. Cette source de pollution supplĂ©mentaire pourrait augmenter avec la fonte de la banquise qui libĂšre des microplastiques jusque-lĂ stockĂ©s dans la glace. Ce travail souligne lâimportance des programmes Ă long terme pour lâĂ©tude des impacts des changements globaux
Tactiques de migration hivernale chez la cigogne blanche (Ciconia ciconia) : patron, sources et conséquences sur la reproduction dans une population en croissance démographique. Sous la direction scientifique de Françoise AMELINEAU et Jean-Marc PAILLISSON et la supervision technique de Hubert DUGUE.
Tactiques de migration hivernale chez la cigogne blanche (Ciconia ciconia) : patron, sources et conséquences sur la reproduction dans une population en croissance démographique. Sous la direction scientifique de Françoise AMELINEAU et Jean-Marc PAILLISSON et la supervision technique de Hubert DUGUE.
Does temporal variation of mercury levels in Arctic seabirds reflect changes in global environmental contamination, or a modification of Arctic marine food web functioning?
International audienc
Arctic climate change and pollution impact little auk foraging and fitness across a decade
International audienc
An automated procedure (v2.0) to obtain positions from light-level geolocators in large-scale tracking of seabirds. A method description for the SEATRACK project
BrĂ„then, V.S., Moe, B., AmĂ©lineau, F., Ekker, M., Fauchald, P.,Helgason, H.H., Johansen, M. K., Merkel, B., Tarroux, A., Ă
ström, J. & StrÞm, H. 2021. An automated procedure (v2.0) to obtain positions from light-level geolocators in large-scale tracking of seabirds. A method description for the SEATRACK project. NINA Report 1893. Norwegian Institute for Nature Research.
Partners in the SEATRACK project have since 2014 deployed >14 000 light-level geolocators on 11 species of seabirds to study their non-breeding distribution in the North Atlantic. Geolocator tags are ideal for large-scale tracking of seabirds being cheap and small. The tags contains a clock and a light sensor that register light levels at fixed intervals. These data are stored in the internal memory and are obtained when the tag is recovered from the bird. From these data two positions per day are calculated by estimating latitude from the length of day and night, and longitude from time of mid-day and mid-night. However, positions cannot be obtained from recorded light-data during the polar night or midnight sun. Further, the latitudinal accuracy is unreliable close to spring and autumn equinox when the length of day and night is similar across the earth.
Using a threshold method, we first identify twilight events, which is the time when light-levels cross a predefined threshold that separate day from night. However, the light-level recordings are affected by environmental factors and the behaviour of the bird that may shade the geolocator or expose it to artificial light. As such, the accuracy is low compared to GPS or Argos tracking devices. A common approach has therefore been to improve the identification of these twilight events by manually inspecting the light-level data. This process is, however, time-consuming and prone to not being fully consistent and reproducible among different persons applying it.
In this report, we describe an automated procedure (v2.0) for obtaining the basic positional dataset in SEATRACK from raw light-level data. The procedure automatically filters and edits the twilight events used for calculating positions. It further removes unrealistic positions using filters on equinox periods, speed, distribution, angle, distance, variation in timing of twilights and midnight sun periods, and produces double smoothed positions. Calibration of sun elevation angles, crucial for producing the final positions, is performed on each track and is the only part involving subjective assessment, but we show that it can be performed consistently and with a high repeatability.
SEATRACK processes light data from >1000 geolocators after each field season, and the database has become one of the largest seabird tracking databases in the world. The automated procedure (v2.0) is a very cost-efficient method for such large-scale tracking and is consistent and reproducible. We have recently updated the entire database using this procedure, replacing all previous data based on the manual procedure and the first version of the automated procedure (v1.0).
This report describes the methods used to obtain positions from geolocators in the SEATRACK project. As the described procedure replace our previous manual method, we show comparisons of the two procedures. The report also provides examples of how to read and visualize the positional data and can serve as the reference for the methods and as a tool for using the data
Starving seabirds: unprofitable foraging and its fitness consequences in Cape gannets competing with fisheries in the Benguela upwelling ecosystem
International audienceFisheries are often accused of starving vulnerableseabirds, yet evidence for this claim is scarce. Foragingenergetics may provide efficient, short-term indicatorsof the fitness status of seabirds competing with fisheries.We used this approach in Cape gannets (Morus capensis)from Malgas Island, South Africa, which feed primarilyon small pelagic fish in the southern Benguela upwellingregion, thereby competing with purse-seine fisheries. Duringtheir 2011â2014 breeding seasons, we determined bodycondition of breeding adult Cape gannets and measuredtheir chick growth rates. In addition to these conventionalfitness indices, we assessed the daily energy expenditure ofbreeding adults using a high-resolution time-energy budgetderived from GPS-tracking and accelerometry data. Forthese same individuals, we also determined prey intakerates using stomach temperature recordings. We found that adult body condition and chick growth rates declinedsignificantly during the study period. Crucially, mostbirds (73 %) studied with electronic recorders spent moreenergy than they gained through foraging, and 80â95 % oftheir feeding dives were unsuccessful. Our results thereforepoint to unprofitable foraging in Cape gannets, witha longer-term fitness cost in terms of adult body conditionand reproductive performance that corresponds to a localpopulation decline. Based on this evidence, we advocatea revision of regional fishing quotas for small pelagic fishand discuss the possibility of an experimental cessation ofpurse-seine fishing activities off the west coast of SouthAfrica. These measures are needed for the ecological andsocio-economical persistence of the broader southern Benguelaupwelling ecosystem