Overfishing and ocean warming are drastically altering the community composition and size structu... more Overfishing and ocean warming are drastically altering the community composition and size structure of marine ecosystems, eliminating large bodied species [1]. Against a backdrop of such environmental change, the heaviest of all bony fish, the ocean sunfish (Mola mola), seems an improbable survivor. Indeed this indolent giant is killed globally as bycatch, and is listed as 'Vulnerable'[2]. We undertook the most extensive aerial surveys of sunfish ever conducted and found surprisingly high abundances off the Atlantic and Mediterranean coasts of Western Europe. With up to 475 individuals per 100 km2, these figures are one order of magnitude higher than abundance estimates for other areas [3-5]. Using bioenergetic modelling, we estimate that each sunfish requires 71 kg day-1 of jellyfish, a biomass intake more than an order of magnitude greater than predicted for a similarly sized teleost. Scaled up to the population level, this equates to a remarkable 20,774 tonnes day-1 of pr...
A B S T R A C T Life history and spatio-temporal patterns of resource utilisation were characteri... more A B S T R A C T Life history and spatio-temporal patterns of resource utilisation were characterised in four Chiastocheta (Diptera: Anthomyiidae) species, whose larvae compete as seed predators on Trollius europaeus fruits. Interspecific co-occurrence was observed in 80% of the resource patches (= Trollius fruits) in the two communities studied. Isolated larvae from all species had a similar food intake, but differed in development time and size at emergence. Different species exhibit contrasting resource exploitation strategies with specific mining patterns and a partial temporal shift. Two species exhibited particularly singular strategies. C. rotundiventris escaped from strong interactions with other species because it was the first species to develop and the only one to exploit the central pith of Trollius fruits. The key role of this species as the main pollinator of the host-plant appears to be a by-product of constraints imposed by occupying a restricted niche. Although the resource is ephemeral due to seed dispersal, C. dentifera, the last species to oviposit, is not disadvantaged because it has a short development time and rapid food intake. The different patterns can partly explain the stability of Chiastocheta communities, but do not prevent competition to occur at high larval densities.
The recent Marine Strategy Framework Directive encourages Member States of the European Union to ... more The recent Marine Strategy Framework Directive encourages Member States of the European Union to achieve ‘Good Environmental Status’ of their waters; that is to protect and restore marine ecosystems and biodiversity. Fulfilling this objective demands an improved knowledge of marine species’ distribution. In 2011/2012, we conducted two 3-months aerial surveys in the English Channel and in the Bay of Biscay to investigate spatio-temporal variations in seabird distribution. A total of 375,015 km2 were surveyed, travelling a distance of 66,550 km on effort. Seabird observations added up to 17,620 in winter and 8,271 in spring/summer. Alcids, gannets, kittiwakes and large gulls were the most frequent among all the observed taxa, though considerable variations occurred in densities and abundance between both seasons. This study of an unprecedented scale intends to produce abundance and density estimates of seabird species in the areas and to improve our knowledge on their distribution. Th...
Cetacean conservation can be achieved by the combined use of spatially defined local management r... more Cetacean conservation can be achieved by the combined use of spatially defined local management regulations like marine protected areas (MPA) and more general policies such as fisheries regulations. In both cases understanding how cetacean distribute and use marine habitats is crucial as well as how this relationship change over time because this determines how cetaceans overlap with sources of anthropic pressures and how spatially defined conservation tools can play their role. The SAMM surveys (Suivi Aérien de la Mégafaune Marine, Aerial Survey of Marine Megafauna), that were conducted in French and adjacent waters of eastern North Atlantic and the Mediterranean seaboards, explore seasonal variations in cetacean distribution and habitat use for the first time at such a large scale. The survey followed a line transect methodology, covering about 90.000 km on effort providing a total number of 2877 cetacean sightings. In order to explore cetacean answers to the seasonal variability ...
Norwegian Northern Gannet Morus bassanus populations exhibit contrasted trends at a regional scal... more Norwegian Northern Gannet Morus bassanus populations exhibit contrasted trends at a regional scale and several colony extinctions occurred in recent decades. In an attempt to understand the ecological drivers of such variability, we tested whether resource availability is a factor limiting the current development of gannetries in the Lofoten/Vesterålen area. Between 2007 and 2010, we recorded arrival and departure times of breeding gannets from two colonies from regions showing contrasting population growth rates during the past two decades. We also recorded the duration of joint attendances by gannet parents at the nest, performed opportunistic diet sampling and counted numbers of occupied nests. Finally, we compiled ring recoveries over a 30-year period to assess inter-colony movements. Norwegian gannet parents spent more time together, attending their chick, and performed shorter foraging trips than those in British and French colonies of similar size. This suggests that, despite...
Overfishing and ocean warming are drastically altering the community composition and size structu... more Overfishing and ocean warming are drastically altering the community composition and size structure of marine ecosystems, eliminating large bodied species [1]. Against a backdrop of such environmental change, the heaviest of all bony fish, the ocean sunfish (Mola mola), seems an improbable survivor. Indeed this indolent giant is killed globally as bycatch, and is listed as 'Vulnerable'[2]. We undertook the most extensive aerial surveys of sunfish ever conducted and found surprisingly high abundances off the Atlantic and Mediterranean coasts of Western Europe. With up to 475 individuals per 100 km2, these figures are one order of magnitude higher than abundance estimates for other areas [3-5]. Using bioenergetic modelling, we estimate that each sunfish requires 71 kg day-1 of jellyfish, a biomass intake more than an order of magnitude greater than predicted for a similarly sized teleost. Scaled up to the population level, this equates to a remarkable 20,774 tonnes day-1 of pr...
A B S T R A C T Life history and spatio-temporal patterns of resource utilisation were characteri... more A B S T R A C T Life history and spatio-temporal patterns of resource utilisation were characterised in four Chiastocheta (Diptera: Anthomyiidae) species, whose larvae compete as seed predators on Trollius europaeus fruits. Interspecific co-occurrence was observed in 80% of the resource patches (= Trollius fruits) in the two communities studied. Isolated larvae from all species had a similar food intake, but differed in development time and size at emergence. Different species exhibit contrasting resource exploitation strategies with specific mining patterns and a partial temporal shift. Two species exhibited particularly singular strategies. C. rotundiventris escaped from strong interactions with other species because it was the first species to develop and the only one to exploit the central pith of Trollius fruits. The key role of this species as the main pollinator of the host-plant appears to be a by-product of constraints imposed by occupying a restricted niche. Although the resource is ephemeral due to seed dispersal, C. dentifera, the last species to oviposit, is not disadvantaged because it has a short development time and rapid food intake. The different patterns can partly explain the stability of Chiastocheta communities, but do not prevent competition to occur at high larval densities.
The recent Marine Strategy Framework Directive encourages Member States of the European Union to ... more The recent Marine Strategy Framework Directive encourages Member States of the European Union to achieve ‘Good Environmental Status’ of their waters; that is to protect and restore marine ecosystems and biodiversity. Fulfilling this objective demands an improved knowledge of marine species’ distribution. In 2011/2012, we conducted two 3-months aerial surveys in the English Channel and in the Bay of Biscay to investigate spatio-temporal variations in seabird distribution. A total of 375,015 km2 were surveyed, travelling a distance of 66,550 km on effort. Seabird observations added up to 17,620 in winter and 8,271 in spring/summer. Alcids, gannets, kittiwakes and large gulls were the most frequent among all the observed taxa, though considerable variations occurred in densities and abundance between both seasons. This study of an unprecedented scale intends to produce abundance and density estimates of seabird species in the areas and to improve our knowledge on their distribution. Th...
Cetacean conservation can be achieved by the combined use of spatially defined local management r... more Cetacean conservation can be achieved by the combined use of spatially defined local management regulations like marine protected areas (MPA) and more general policies such as fisheries regulations. In both cases understanding how cetacean distribute and use marine habitats is crucial as well as how this relationship change over time because this determines how cetaceans overlap with sources of anthropic pressures and how spatially defined conservation tools can play their role. The SAMM surveys (Suivi Aérien de la Mégafaune Marine, Aerial Survey of Marine Megafauna), that were conducted in French and adjacent waters of eastern North Atlantic and the Mediterranean seaboards, explore seasonal variations in cetacean distribution and habitat use for the first time at such a large scale. The survey followed a line transect methodology, covering about 90.000 km on effort providing a total number of 2877 cetacean sightings. In order to explore cetacean answers to the seasonal variability ...
Norwegian Northern Gannet Morus bassanus populations exhibit contrasted trends at a regional scal... more Norwegian Northern Gannet Morus bassanus populations exhibit contrasted trends at a regional scale and several colony extinctions occurred in recent decades. In an attempt to understand the ecological drivers of such variability, we tested whether resource availability is a factor limiting the current development of gannetries in the Lofoten/Vesterålen area. Between 2007 and 2010, we recorded arrival and departure times of breeding gannets from two colonies from regions showing contrasting population growth rates during the past two decades. We also recorded the duration of joint attendances by gannet parents at the nest, performed opportunistic diet sampling and counted numbers of occupied nests. Finally, we compiled ring recoveries over a 30-year period to assess inter-colony movements. Norwegian gannet parents spent more time together, attending their chick, and performed shorter foraging trips than those in British and French colonies of similar size. This suggests that, despite...
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