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Henri Weimerskirch - One of the best experts on this subject based on the ideXlab platform.
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Albatrosses redirect flight towards vessels at the limit of their visual range
Marine Ecology Progress Series, 2015Co-Authors: Julien Collet, Samantha C Patrick, Henri WeimerskirchAbstract:Seabird-fishery interactions are important to seabird ecology and conservation since some species obtain a significant amount of food from fisheries, but mortality from bycatch is a primary cause of population declines in several species. While the availability of high resolution GPS data for both Seabirds and vessels over the past few years has allowed analyses of fine-scale behavioural responses of Seabirds near fishing vessels, little information is available on the distance at which Seabirds respond to vessels. Indeed, previous studies have focused on the foraging behaviour of individuals within the vicinity of vessels but have not considered the approach phase of birds. Here we provide such an estimate by examining changes in the flight direction of GPS-tracked wandering albatrosses breeding on the Crozet Islands in response to the toothfish fishing fleet operating around the breeding grounds, monitored using GPS vessel monitoring system data. We show that although we detect increases in feeding behaviour only when albatrosses are within 3 km of boats, they display clear changes in flight direction, towards vessels, at distances up to 30 km. This distance is nearly 3 times as large as previous estimates, almost reaching the theoretical maximum visual range of an albatross. We discuss these results in the light of previous estimates, and pinpoint factors likely to affect the attraction distance. We suggest that this simple estimate of attraction distance could be investigated in other seabird-fishery systems, to improve our understanding of the factors affecting seabird interaction behaviour, and thus better predict when overlap will lead to interactions.
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Local depletion by a fishery can affect seabird foraging
Journal of Applied Ecology, 2012Co-Authors: Sophie Bertrand, Yann Tremblay, Rocio Joo, Christophe Barbraud, Claude Arbulu Smet, Henri WeimerskirchAbstract:International audience1. Long-term demographic studies show that seabird populations may suffer from competition with fisheries. Understanding this process is critical for the implementation of an ecosystem approach to fisheries management (EAF). Existing studies rely mostly on indirect clues: overlaps between seabird foraging and fishing areas, comparing fish catches by Seabirds and vessels. 2. The study is based on a GPS tracking experiment performed in 2007 on one of the main guano-producing seabird species, the Peruvian booby, breeding on an island near the major port for anchovy landings in Peru. The fishery, which is entirely monitored by a Vessel Monitoring System, opened the day we began the tracking experiment, providing a unique opportunity to examine the day-to-day effects of an intense fishing activity on seabird foraging behaviour. 3. We observed a significant increase in the range of the daily trips and distances of the dives by birds from the colony. This increase was significantly related to the concomitant fishing activity. Seabirds progressively became more segregated in space from the vessels. Their increased foraging effort was significantly related to the growing quantity of anchovy removals by the fishery. In addition, daily removals by the fishery were at least 100 times greater than the daily anchovy requirement of the seabird colonies. We conclude that Seabirds needed to forage farther to cope with the regional prey depletion created by the intensive fishing behaviour of this open access fishery. 4. Synthesis and applications. We show that the foraging efficiency of breeding Seabirds may be significantly affected by not only the global quantity, but also the temporal and spatial patterns of fishery removals. Together with an ecosystem-based definition of the fishery quota, an EAF should limit the risk of local depletion around breeding colonies using, for instance, adaptive marine protected areas
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Competition for the same fish: local depletion by a fishery can affect seabird foraging
Journal of Applied Ecology, 2012Co-Authors: Sophie Bertrand, Yann Tremblay, Rocio Joo, Claude Arbulu Smet, Christophe Barbraud, Henri WeimerskirchAbstract:1. Long-term demographic studies show that seabird populations may suffer from competition with fisheries. Understanding this process is critical for the implementation of an ecosystem approach to fisheries management (EAF). Existing studies rely mostly on indirect clues: overlaps between seabird foraging and fishing areas, comparing fish catches by Seabirds and vessels. 2. The study is based on a GPS tracking experiment performed in 2007 on one of the main guano-producing seabird species, the Peruvian booby, breeding on an island near the major port for anchovy landings in Peru. The fishery, which is entirely monitored by a Vessel Monitoring System, opened the day we began the tracking experiment, providing a unique opportunity to examine the day-to-day effects of an intense fishing activity on seabird foraging behaviour. 3. We observed a significant increase in the range of the daily trips and distances of the dives by birds from the colony. This increase was significantly related to the concomitant fishing activity. Seabirds progressively became more segregated in space from the vessels. Their increased foraging effort was significantly related to the growing quantity of anchovy removals by the fishery. In addition, daily removals by the fishery were at least 100 times greater than the daily anchovy requirement of the seabird colonies. We conclude that Seabirds needed to forage farther to cope with the regional prey depletion created by the intensive fishing behaviour of this open access fishery. 4. Synthesis and applications. We show that the foraging efficiency of breeding Seabirds may be significantly affected by not only the global quantity, but also the temporal and spatial patterns of fishery removals. Together with an ecosystem-based definition of the fishery quota, an EAF should limit the risk of local depletion around breeding colonies using, for instance, adaptive marine protected areas.
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Tracking Seabirds to identify potential Marine Protected Areas in the tropical western Indian Ocean
Biological Conservation, 2012Co-Authors: Matthieu Le Corre, Audrey Jaeger, Henri Weimerskirch, Jaime A. Ramos, James C. Russell, Patrick Pinet, Michelle A. Kappes, Teresa Catry, Nirmal Shah, Sébastien JaquemetAbstract:We conducted a regional tracking program on Seabirds in order to identify major forging hotspots and potential Marine Protected Areas in the tropical western Indian Ocean. Thirty-one species of Seabirds breed in the region, totaling 7.4 million pairs. The main breeding grounds are in the Seychelles, in the Mozambique Channel and in the Mascarene. Seven pelagic species have been tracked so far from eight different islands of the region. Using count per sector analysis we identified five major oceanic foraging hotspots, among which three include the breeding colonies and two are oceanic areas not connected to a breeding island. We found important overlaps between most of these seabird foraging hotspots and potential threats (industrial fishery targeting surface dwelling tunas and marine pollution due to maritime routes) suggesting that in these regions Seabirds may be at risk when foraging. Although this analysis is based on a limited number of tracking studies, the knowledge on seabird distribution at sea has increased tremendously in the last 6 years in the tropical western Indian Ocean, and this trend will continue, as research is ongoing. The data, we present here for the first time in a single synthesis show clear spatial patterns that identify high priority locations for designation as Marine Protected Areas in the tropical western Indian Ocean.
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Resource partitioning within a tropical seabird community: new information from stable isotopes
Marine Ecology Progress Series, 2008Co-Authors: Yves Cherel, Matthieu Le Corre, Sébastien Jaquemet, F. Ménard, Patrick Richard, Henri WeimerskirchAbstract:Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical Seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood δ13C and δ15N values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (δ13C), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F. ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (δ15N), which is in agreement with a diet mainly based on flying fish and squid. Feather δ13C and δ15N values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable isotope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on different prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, Seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower δ15N values than the deeper-dwelling bigeye tuna and swordfish. We conclude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical Seabirds year round, and for determining sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.
Matthieu Le Corre - One of the best experts on this subject based on the ideXlab platform.
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Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation?
Biological Conservation, 2015Co-Authors: David Ringler, James C. Russell, Matthieu Le CorreAbstract:Rats contribute to the decline of tropical seabird populations by affecting their breeding success through direct predation of eggs and chicks. When they coexist with other predators, invasive rats may also generate indirect interactions via the changes they impose on the structure of communities and trophic interactions following invasion (‘hyperpredation process’), or when apex predators are eradicated from the ecosystem (‘mesopredator release effect’). Understanding these effects is necessary to implement restoration operations that actually benefit threatened seabird populations. We investigated these processes on two French tropical seabird islands of the western Indian Ocean, Europa and Juan de Nova, where black rats coexist with two different apex predator species (introduced cats and potentially native barn owls). The parallel use of several methods (diet analysis, stable isotopes, seabird monitoring) to identify trophic roles of rats revealed that the direct impact of rats on Seabirds was particularly high on Europa where only rats and owls occur, with high consumption of chicks resulting in low breeding success for several seabird species. We also suggested that hyperpredation associated with top-down regulation of cats is occurring on Juan de Nova, although territoriality of cats may buffer this process. Conversely we found evidence that mesopredator release effect is unlikely, irrespective of the apex predator identity. Considering the most likely effects on both islands we provided recommendations on eradication priorities to mitigate the risk of local extinction that Seabirds are currently facing.
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Tracking Seabirds to identify potential Marine Protected Areas in the tropical western Indian Ocean
Biological Conservation, 2012Co-Authors: Matthieu Le Corre, Audrey Jaeger, Henri Weimerskirch, Jaime A. Ramos, James C. Russell, Patrick Pinet, Michelle A. Kappes, Teresa Catry, Nirmal Shah, Sébastien JaquemetAbstract:We conducted a regional tracking program on Seabirds in order to identify major forging hotspots and potential Marine Protected Areas in the tropical western Indian Ocean. Thirty-one species of Seabirds breed in the region, totaling 7.4 million pairs. The main breeding grounds are in the Seychelles, in the Mozambique Channel and in the Mascarene. Seven pelagic species have been tracked so far from eight different islands of the region. Using count per sector analysis we identified five major oceanic foraging hotspots, among which three include the breeding colonies and two are oceanic areas not connected to a breeding island. We found important overlaps between most of these seabird foraging hotspots and potential threats (industrial fishery targeting surface dwelling tunas and marine pollution due to maritime routes) suggesting that in these regions Seabirds may be at risk when foraging. Although this analysis is based on a limited number of tracking studies, the knowledge on seabird distribution at sea has increased tremendously in the last 6 years in the tropical western Indian Ocean, and this trend will continue, as research is ongoing. The data, we present here for the first time in a single synthesis show clear spatial patterns that identify high priority locations for designation as Marine Protected Areas in the tropical western Indian Ocean.
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Resource partitioning within a tropical seabird community: new information from stable isotopes
Marine Ecology Progress Series, 2008Co-Authors: Yves Cherel, Matthieu Le Corre, Sébastien Jaquemet, F. Ménard, Patrick Richard, Henri WeimerskirchAbstract:Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical Seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood δ13C and δ15N values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (δ13C), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F. ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (δ15N), which is in agreement with a diet mainly based on flying fish and squid. Feather δ13C and δ15N values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable isotope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on different prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, Seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower δ15N values than the deeper-dwelling bigeye tuna and swordfish. We conclude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical Seabirds year round, and for determining sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.
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Assessment of the seabird community of the Mozambique Channel and its potential use as an indicator of tuna abundance
Estuarine Coastal and Shelf Science, 2005Co-Authors: Matthieu Le Corre, Sébastien JaquemetAbstract:Tropical Seabirds are known to associate with aggregations of surface dwelling predators, like tunas when feeding. Some species are even regarded as near obligate commensals of tunas. As food is one of the main factors that shape breeding strategies and determine breeding success of Seabirds, it is of interest to test the hypothesis that variations in tuna abundance may have effects on foraging success and thus on breeding parameters of tropical Seabirds. The Mozambique Channel is appropriate for such a study because relative tuna abundance is assessed annually (through fishery catches) and seabird populations are abundant. A regional synopsis shows that at least 3.034 million pairs of Seabirds breed on islands of the Mozambique Channel, 99.3% being sooty terns. This super-abundant seabird is strongly associated with tuna and marine mammals when feeding. More than 99% of the sooty tern population of the Mozambique Channel breeds at three remote coralline islands, namely Juan de Nova (66%), Europa (25%) and Glorieuses (9%). Various breeding parameters (breeding population size, breeding time, growth rate of the chicks, daily food intake, diet) are studied at these three sites in order to investigate their relation to the marine environment (including tuna abundance). A preliminary estimate is made of the quantity of food eaten by the sooty tern population.
Sébastien Jaquemet - One of the best experts on this subject based on the ideXlab platform.
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Tracking Seabirds to identify potential Marine Protected Areas in the tropical western Indian Ocean
Biological Conservation, 2012Co-Authors: Matthieu Le Corre, Audrey Jaeger, Henri Weimerskirch, Jaime A. Ramos, James C. Russell, Patrick Pinet, Michelle A. Kappes, Teresa Catry, Nirmal Shah, Sébastien JaquemetAbstract:We conducted a regional tracking program on Seabirds in order to identify major forging hotspots and potential Marine Protected Areas in the tropical western Indian Ocean. Thirty-one species of Seabirds breed in the region, totaling 7.4 million pairs. The main breeding grounds are in the Seychelles, in the Mozambique Channel and in the Mascarene. Seven pelagic species have been tracked so far from eight different islands of the region. Using count per sector analysis we identified five major oceanic foraging hotspots, among which three include the breeding colonies and two are oceanic areas not connected to a breeding island. We found important overlaps between most of these seabird foraging hotspots and potential threats (industrial fishery targeting surface dwelling tunas and marine pollution due to maritime routes) suggesting that in these regions Seabirds may be at risk when foraging. Although this analysis is based on a limited number of tracking studies, the knowledge on seabird distribution at sea has increased tremendously in the last 6 years in the tropical western Indian Ocean, and this trend will continue, as research is ongoing. The data, we present here for the first time in a single synthesis show clear spatial patterns that identify high priority locations for designation as Marine Protected Areas in the tropical western Indian Ocean.
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Resource partitioning within a tropical seabird community: new information from stable isotopes
Marine Ecology Progress Series, 2008Co-Authors: Yves Cherel, Matthieu Le Corre, Sébastien Jaquemet, F. Ménard, Patrick Richard, Henri WeimerskirchAbstract:Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical Seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood δ13C and δ15N values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (δ13C), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F. ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (δ15N), which is in agreement with a diet mainly based on flying fish and squid. Feather δ13C and δ15N values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable isotope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on different prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, Seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower δ15N values than the deeper-dwelling bigeye tuna and swordfish. We conclude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical Seabirds year round, and for determining sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.
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Assessment of the seabird community of the Mozambique Channel and its potential use as an indicator of tuna abundance
Estuarine Coastal and Shelf Science, 2005Co-Authors: Matthieu Le Corre, Sébastien JaquemetAbstract:Tropical Seabirds are known to associate with aggregations of surface dwelling predators, like tunas when feeding. Some species are even regarded as near obligate commensals of tunas. As food is one of the main factors that shape breeding strategies and determine breeding success of Seabirds, it is of interest to test the hypothesis that variations in tuna abundance may have effects on foraging success and thus on breeding parameters of tropical Seabirds. The Mozambique Channel is appropriate for such a study because relative tuna abundance is assessed annually (through fishery catches) and seabird populations are abundant. A regional synopsis shows that at least 3.034 million pairs of Seabirds breed on islands of the Mozambique Channel, 99.3% being sooty terns. This super-abundant seabird is strongly associated with tuna and marine mammals when feeding. More than 99% of the sooty tern population of the Mozambique Channel breeds at three remote coralline islands, namely Juan de Nova (66%), Europa (25%) and Glorieuses (9%). Various breeding parameters (breeding population size, breeding time, growth rate of the chicks, daily food intake, diet) are studied at these three sites in order to investigate their relation to the marine environment (including tuna abundance). A preliminary estimate is made of the quantity of food eaten by the sooty tern population.
Yves Cherel - One of the best experts on this subject based on the ideXlab platform.
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Wide Range of Mercury Contamination in Chicks of Southern Ocean Seabirds
PLoS ONE, 2013Co-Authors: Pierre Blévin, Carravieri Alice, Chastel Olivier, Paco Bustamante, Yves CherelAbstract:Using top predators as sentinels of the marine environment, Hg contamination was investigated within the large subantarctic seabird community of Kerguelen Islands, a remote area from the poorly known Southern Indian Ocean. Chicks of 21 sympatric Seabirds presented a wide range of Hg concentrations, with the highest contaminated species containing ~102 times more feather Hg than the less contaminated species. Hence, Kerguelen Seabirds encompass the whole range of chick feather Hg values that were previously collected worldwide in poorly industrialized localities. Using stable isotopes, the effects of foraging habitats (reflected by δ13C) and trophic positions (reflected by δ15N) on Hg concentrations were investigated. Species-related Hg variations were highly and positively linked to feather δ15N values, thus highlighting the occurrence of efficient Hg biomagnification processes within subantarctic marine trophic webs. By contrast, Hg contamination overall correlated poorly with feeding habitats, because of the pooling of species foraging within different isotopic gradients corresponding to distinct seabird habitats (benthic, pelagic, neritic and oceanic). However, when focusing on oceanic Seabirds, Hg concentration was related to feather δ13C values, with species feeding in colder waters (lower δ13C values) south of Kerguelen Islands being less prone to be contaminated than species feeding in northern warmer waters (higher δ13C values). Within the context of continuous increase in global Hg emissions, Kerguelen Islands that are located far away from anthropogenic sources can be considered as an ideal study site to monitor the temporal trend of global Hg contamination. The present work helps selecting some seabird species as sentinels of environmental pollution according to their high Hg concentrations and their contrasted foraging ecology.
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How do cephalopods become available to Seabirds: can fish gut contents from tuna fishing vessels be a major food source of deep-dwelling cephalopods?
ICES Journal of Marine Science, 2013Co-Authors: José C. Xavier, Yves Cherel, Jim Roberts, Uwe PiatkowskiAbstract:Cephalopods are important prey for numerous seabird species. However, the physical mechanisms by which cephalopods (particularly species considered as deep-dwelling) become available to Seabirds are poorly understood, and it has recently been suggested that the discarded stomachs of gutted fish captured by tuna longliners can be a major source of deep-dwelling species. Here, we identify some deep-dwelling cephalopods that appear in the diet of Seabirds, review the current knowledge of their vertical distribution, and compare the stomach contents of commercially captured tuna with those of Seabirds foraging in the same area. The limited available information leads us to conclude that tuna longliners are unlikely to be a major source of deep-dwelling cephalopods for Seabirds. However, much more information is required on the ecology of seabird prey, particularly commercially unexploited cephalopod species, which may be obtained from scientific cruises devoted to cephalopod biological research. In addition multispecies/ foodweb modelling studies may be required to explore potential interactions between Seabirds, their predators and prey, and commercial fishing operations.
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Resource partitioning within a tropical seabird community: new information from stable isotopes
Marine Ecology Progress Series, 2008Co-Authors: Yves Cherel, Matthieu Le Corre, Sébastien Jaquemet, F. Ménard, Patrick Richard, Henri WeimerskirchAbstract:Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical Seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood δ13C and δ15N values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (δ13C), one used by sooty tern Sterna fuscata and white-tailed tropicbird Phaethon lepturus and one used by red-footed booby Sula sula and great Fregata minor and lesser F. ariel frigatebirds. Seabird species overall encompassed less than 1 trophic level (δ15N), which is in agreement with a diet mainly based on flying fish and squid. Feather δ13C and δ15N values showed that the trophic structure of the community was different during the breeding and non-breeding (moulting) periods, suggesting a shift in the feeding ecology when adult birds were no longer central-place foragers. The stable isotope method underlined sex-related (red-footed booby) and age-related (great frigatebird immatures and adults) feeding strategies. It also suggested that breeding adults could feed themselves on different prey than those given to their chicks (sooty tern). Within the tropical pelagic ecosystem, Seabirds overall shared the same trophic level as large predatory fishes (albacore, yellowfin and skipjack tunas), but they had lower δ15N values than the deeper-dwelling bigeye tuna and swordfish. We conclude that analyzing stable isotope values in blood and feathers appears to be a promising alternative method for investigating food and feeding ecology of tropical Seabirds year round, and for determining sex- and age-related differences in their foraging strategies. A limitation of the method is the lack of information on marine isoscapes; future studies aimed at isotopically characterizing the tropical marine environment could help to associate consumer signatures to geographic origins.
Mark L Mallory - One of the best experts on this subject based on the ideXlab platform.
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Parasites of Seabirds: A survey of effects and ecological implications
Advances in Marine Biology, 2019Co-Authors: Junaid S. Khan, Jennifer Provencher, Mark Forbes, Mark L Mallory, Camille Lebarbenchon, Karen MccoyAbstract:Parasites are ubiquitous in the environment, and can cause negative effects in their host species. Importantly, Seabirds can be long-lived and cross multiple continents within a single annual cycle, thus their exposure to parasites may be greater than other taxa. With changing climatic conditions expected to influence parasite distribution and abundance, understanding current level of infection, transmission pathways and population-level impacts are integral aspects for predicting ecosystem changes, and how climate change will affect seabird species. In particular, a range of micro- and macro-parasites can affect seabird species, including ticks, mites, helminths, viruses and bacteria in gulls, terns, skimmers, skuas, auks and selected phalaropes (Charadriiformes), tropicbirds (Phaethontiformes), penguins (Sphenisciformes), tubenoses (Procellariiformes), cormorants, frigatebirds, boobies, gannets (Suliformes), and pelicans (Pelecaniformes) and marine seaducks and loons (Anseriformes and Gaviiformes). We found that the seabird orders of Charadriiformes and Procellariiformes were most represented in the parasite-seabird literature. While negative effects were reported in Seabirds associated with all the parasite groups, most effects have been studied in adults with less information known about how parasites may affect chicks and fledglings. We found studies most often reported on negative effects in seabird hosts during the breeding season, although this is also the time when most seabird research occurs. Many studies report that external factors such as condition of the host, pollution, and environmental conditions can influence the effects of parasites, thus cumulative effects likely play a large role in how parasites influence Seabirds at both the individual and population level. With an increased understanding of parasite-host dynamics it is clear that major environmental changes, often those associated with human activities, can directly or indirectly affect the distribution, abundance, or virulence of parasites and pathogens.
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garbage in guano microplastic debris found in faecal precursors of Seabirds known to ingest plastics
Science of The Total Environment, 2018Co-Authors: Jennifer F Provencher, Jesse C Vermaire, Stephanie Averygomm, Birgit M Braune, Mark L MalloryAbstract:Plastic pollution is global environmental contaminant. Plastic particulates break down into smaller fragments in the environment, and these small pieces are now commonly found to be ingested by animals. To date, most plastic ingestion studies have focused on assessing retained plastics or regurgitated plastics, but it is likely that animals also excrete plastic and other debris items. We examined the terminal portion of the gastrointestinal tract of a seabird known to commonly ingest plastics, the Northern Fulmar (Fulmarus glacialis), to determine if Seabirds excrete microplastics and other debris via their guano. We also examine how guano collections may be used as an indicator of retained plastics. The frequency of occurrence of microplastics did not correlate between the gut and faecal precursor samples, but there was a positive relationship between the number of pieces of plastics in the gut and the number of microplastics in the guano. Our findings suggest that Seabirds are acting as vectors of microplastics and debris in the marine environment where their guano accumulates around their colonies. This transport of microplastics and debris by colonial Seabirds needs to be further examined, and considered when designing environmental monitoring for microplastics in regions where seabird colonies are found.
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Populations and trends of Canadian Arctic Seabirds
Polar Biology, 2012Co-Authors: Anthony J. Gaston, Mark L Mallory, H. Grant GilchristAbstract:Canada’s eastern Arctic (Nunavut and Arctic Quebec—Nunavik, N of 60°) supports large numbers of Seabirds in summer. Seabird breeding habitat in this region includes steep, rocky coasts and low-lying coasts backed by lowland sedge-meadow tundra. The former areas support colonial cliff- and scree-nesting Seabirds, such as murres and fulmars; the latter inland or coastal Seabirds, such as terns, gulls and jaegers. The region supports some 4 million breeding Seabirds, of which the most numerous are thick-billed murres (Uria lomvia; 75%), black guillemots (Cepphus grylle; 9%), northern fulmars (Fulmarus glacialis; 8%) and black-legged kittiwakes (Rissa tridactyla; 6%). The majority of Arctic Seabirds breed in a small number of very large colonies (>10,000 birds), but there are also substantial numbers of non-colonial or small-colony breeding populations that are scattered more widely (e.g. terns, guillemots). Population trends among Canadian Arctic Seabirds over the past few decades have been variable, with no strongly negative trends except for the rare ivory gull (Pagophila eburnea): this contrasts with nearby Greenland, where several species have shown steep declines. Although current seabird trends raise only small cause for concern, climate amelioration may enable increased development activities in the north, potentially posing threats to some Seabirds on their breeding grounds.
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trophic position influences the efficacy of Seabirds as metal biovectors
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Neal Michelutti, Mark L Mallory, Jules M. Blais, Marianne S. V. Douglas, Jaclyn Brash, Joshua R Thienpont, Lynda E Kimpe, John P. SmolAbstract:Seabirds represent a well documented biological transport pathway of nutrients from the ocean to the land by nesting in colonies and providing organic subsidies (feces, carcasses, dropped food) to these sites. We investigated whether Seabirds that feed at different trophic levels vary in their potency as biovectors of metals, which can bioaccumulate through the marine foodweb. Our study site, located on a small island in Arctic Canada, contains the unique scenario of two nearby ponds, one of which receives inputs almost exclusively from upper trophic level piscivores (Arctic terns, Sterna paradisaea) and the other mainly from lower trophic level molluscivores (common eiders, Somateria mollissima). We used dated sediment cores to compare differences in diatoms, metal concentrations and also stable isotopes of nitrogen (δ15N), which reflect trophic position. We show that the Seabirds carry species-specific mixtures of metals that are ultimately shunted to their nesting sites. For example, sediments from the tern-affected pond recorded the highest levels of δ15N and the greatest concentrations of metals that are known to bioaccumulate, including Hg and Cd. In contrast, the core from the eider-affected site registered lower δ15N values, but higher concentrations of Pb, Al, and Mn. These metals have been recorded at their greatest concentrations in eiders relative to other Seabirds, including Arctic terns. These data indicate that metals may be used to track seabird population dynamics, and that some metal tracers may even be species-specific. The predominance of large seabird colonies on every continent suggests that similar processes are operating along coastlines worldwide.
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Seabirds as indicators of aquatic ecosystem conditions: a case for gathering multiple proxies of seabird health.
Marine pollution bulletin, 2009Co-Authors: Mark L Mallory, Stacey A. Robinson, Craig E. Hebert, Mark R. ForbesAbstract:The use of Seabirds as sentinels of the condition of aquatic ecosystems has been well-established. Large environmental perturbations to aquatic food webs (e.g., chemical contamination, overfishing, particulate pollution) have all been detected or monitored by tracking Seabirds at colonies. However, Seabirds may elicit more subtle, sublethal responses that can also be used to track ecosystem health, or the health of seabird populations. In this article, we advocate for field researchers to plan a priori to collect a broader suite of samples when handling Seabirds, and to reach out for collaboration with specialists (e.g., parasitologists, wildlife veterinarians). Collectively, such efforts will greatly improve our ability to establish baseline physiological and chemical levels for Seabirds, against which we can detect future changes in aquatic ecosystems.
