Status and conservation of the grey seal, Halichœrus grypus, in France

Vincent, Cécile; Fedak, Michael A.; McConnell, Bernie; Meynier, Laureline; Saint-Jean, Christophe; Ridoux, Vincent

doi:10.1016/j.biocon.2005.04.022

Cited by 31 publications

(45 citation statements)

References 23 publications

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“…Its relative abundance and pup production remained very low in the 1990s (Härkönen et al, in press), at the same time as pup production in local British populations was increasing by 6% per annum. However, the rate of increase for seals in the Molène archipelago outside the breeding period (+7% per year, Vincent et al, 2005) was very similar to that observed at British colonies. Individual grey seals have very large ranges outside the breeding season and individuals from different local populations may overlap extensively at this time.…”

Section: Discussionsupporting

confidence: 76%

“…This confirms that there was no preferential use of the site by males during any period. However, the overall fidelity of individual males to the Molène archipelago is very high (Vincent et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Abundance estimates for this colony are still missing. Censuses were conducted between 1991 and 2000, and showed an increase in the relative abundance of seals at haul-out sites of 7% per year (Vincent et al, 2005), similar to that observed in Great Britain during the same period (Hiby et al, 1996). These censuses indicated seasonal variations in the relative Maureen Gerondeau* ‡ , Christophe Barbraud † , Vincent Ridoux* and Cécile Vincent* abundance and composition by sex and age of the group, and satellite tracking highlighted individual movements to other grey seal colonies in the south-western British Isles.…”

Section: Introductionmentioning

confidence: 86%

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Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture

Gerondeau

Barbraud²,

Ridoux³

et al. 2007

J. Mar. Biol. Ass.

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Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture-mark-recapture It has been suggested that the large grey seal colonies around the British Isles form local populations within a metapopulation, and that seal movements outside the breeding season lead to considerable overlap between individual home ranges. Individual behaviour and population dynamics of small peripheral colonies may also play a role in the metapopulation. We studied the French grey seal colony of the Molène archipelago, at the southern-most limit of the species' range. We analysed photo-identification data with capture-mark-recapture techniques in order to estimate the total seasonal abundance of grey seals in the archipelago and to quantify the seasonal rates of occurrence or movements of male and female seals. We found that between 58 (95% confidence interval: 48-71) and 98 (95% CI: 75-175) individuals hauled out in the archipelago during the summers of 1999 and 2000. The use of multistate models allowed the assessment of seasonal site fidelity and indicated that it varied between key periods of the annual cycle, particularly for females. Males showed a constant fidelity rate of 56% from one season to another. Hence, even though they showed high inter-annual site fidelity, they did not seem to have a preferred season for using the archipelago. On the contrary, female grey seals showed the highest site fidelity between moult and summer (around 80%), and the lowest fidelity between summer and the breeding period (34-43%). Thus, females seem to use the Molène archipelago preferentially in summer and leave the site before the breeding season, which explains the very low local pup production. Philopatry may explain this pre-breeding emigration, and we suggest that most grey seals observed in the Molène archipelago were born and breed in other local breeding populations, probably the south-western British Isles.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 86%

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Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture

Gerondeau

Barbraud²,

Ridoux³

et al. 2007

J. Mar. Biol. Ass.

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“…Harbour porpoises and grey seals are natural inhabitants of the coasts of northwest France, in the region of Brittany (Vincent et al 2005;Jung et al 2009). The diet of harbour porpoises (Walker et al 1998;Santos & Pierce 2003;Santos et al 2004;De Pierrepont et al 2005;MacLeod et al 2007) and grey seals (Bowen & Harrison 1994;Beck et al 2005;Parsons et al 2005;Ridoux et al 2007;Lundström et al 2010) have been analysed previously, but both species still deserve special attention in this particular geographic area.…”

Section: Please Scroll Down For Articlementioning

confidence: 99%

“…The grey seal, a flagship species of marine mammals in Brittany, is distributed in the North Atlantic temperate to subpolar waters. The Molène archipelago in the Iroise Sea is at the southern limit of its distribution range (Vincent et al 2005). The interactions of both marine mammal species with fisheries need to be specified in terms of by-catch and of competition for the fish resources.…”

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confidence: 99%

DNA barcoding for the identification of soft remains of prey in the stomach contents of grey seals (Halichoerus grypus) and harbour porpoises (Phocoena phocoena)

Méheust

Alfonsi

Ménec

et al. 2014

Marine Biology Research

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In recent decades, grey seals (Halichoerus grypus) and harbour porpoises (Phocoena phocoena) have become more numerous along the coasts of Brittany in northwestern France. Their interactions with fisheries are of increasing concern and diet analyses are becoming a requirement to determine the actual overlap between species targeted by fisheries and marine mammal prey. However, as only a few stranded or by-caught animals are available to investigate the diet of these top predators, it is necessary to optimize the results obtained from each animal sampled by increasing the rate of prey species determination in stomach contents. We used a combined analysis of stomach contents, based on prey hard remains and, in parallel, a simple DNA barcoding approach to identify the soft remains. Seven grey seal stomachs and three harbour porpoise stomachs have been analysed. The combined approach, making use of visual observation as well as DNA analysis, increased the identification of prey items by around 32% for grey seal and by 21% for harbour porpoise. Fish species identified include Mediterranean and Atlantic horse mackerel (Trachurus mediterraneus and Trachurus trachurus), Atlantic mackerel (Scomber scombrus), ballan and cuckoo wrasse (Labrus bergylta and Labrus mixtus), European seabass (Dicentrarchus labrax), Atlantic pollock (Pollachius pollachius), European conger (Conger conger) and garfish (Belone belone). One fish species (L. bergylta) was identified only with DNA methods. An area-specific diet for the grey seal in the Iroise Sea, proposed by others in a previous study, seems to be supported.

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Habitat selection of gray seals (Halichoerus grypus) in a marine protected area in France

et al. 2015

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In France, the first marine national park was set up in 2007 in the Iroise Sea, western Brittany, encompassing several Special Areas of Conservation (SAC). The park is resident to 1 of only 3 gray seal colonies in France. The at‐sea habitat use of gray seals in the marine park is poorly understood and direct interactions with human activities are expected. We investigated habitat selection of gray seals within the marine park to provide spatial planning recommendations to local conservation management. We obtained data from 19 seals tracked between 2010 and 2013. We used generalized linear models to investigate their habitat selection using distance to haulout, distance to shore, bathymetry, tidal current, and sediment type as explanatory variables. The tracked individuals spent 67% of their time within the boundaries of the marine park. We investigated return trips to focus on habitat selection within the Iroise Sea. The deviance explained by the final model was 76%. Distance to haulout explained 47% of the deviance (seals selected short distances), bathymetry explained 40% (with bimodal selection for waters shallower than 50 m or deeper than 150 m), distance to shore explained 6% (selected distances less than 40 km), current explained 5% (selected weak currents), and sediment explained 2% (selected rocky areas). Habitat selection was concentrated in shallow waters located in the main archipelago of the marine park. The map of selected habitat will help identify potential conflicts of space use between seals and human activities such as fishing and leisure activities. This study has an important ecological and management value. It is the first of its kind in a marine park in France, and one of the few studies of gray seals at the periphery of their range. © 2015 The Wildlife Society.

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Status and conservation of the grey seal, Halichœrus grypus, in France

Cited by 31 publications

References 23 publications

Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture

Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture

DNA barcoding for the identification of soft remains of prey in the stomach contents of grey seals (Halichoerus grypus) and harbour porpoises (Phocoena phocoena)

Habitat selection of gray seals (Halichoerus grypus) in a marine protected area in France

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