Scale-dependent foraging behaviour and habitat associations of two sympatric marine top predators.
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| Title: | Scale-dependent foraging behaviour and habitat associations of two sympatric marine top predators. |
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| Authors: | Carter, Matt I. D.1 (AUTHOR) midc@st-andrews.ac.uk, Aarts, Geert2,3 (AUTHOR), Brasseur, Sophie M. J. M.2 (AUTHOR), Hastie, Gordon D.1 (AUTHOR), Moss, Simon E. W.1 (AUTHOR), Nabe-Nielsen, Jacob4 (AUTHOR), Teilmann, Jonas4 (AUTHOR), Thompson, Dave1 (AUTHOR), Thompson, Paul M.5 (AUTHOR), Vincent, Cécile6 (AUTHOR), Russell, Debbie J. F.1,7 (AUTHOR) dr60@st-andrews.ac.uk |
| Source: | Landscape Ecology. Feb2026, Vol. 41 Issue 2, p1-22. 22p. |
| Subject Terms: | *Foraging behavior, *Harbor seal, *Predatory aquatic animals, *Habitats, *Habitat selection, *Gray seal |
| Geographic Terms: | North Sea |
| Abstract: | Context: Theoretical research has considered how animals should optimise foraging strategies to maximise fitness, adapting search scale to exploit different habitats and minimise competition. Empirical studies have described multi-scale area-restricted search (ARS) strategies for some species, but the physical and biological mechanisms underpinning such behaviour are rarely studied. Objectives: Our objectives were to quantify the presence, prevalence, and habitat associations of scale-dependent foraging for two sympatric seal species, accounting for regional variation across the seascape. Methods: We analyse a GPS telemetry dataset of 116 grey (Halichoerus grypus) and 325 harbour seals (Phoca vitulina) tracked throughout the North Sea. We test the existence of multi-scale ARS, comparing hidden Markov models (HMMs) with two ARS states against more conventional HMMs (one ARS state). We quantify regional variation and examine the scale-dependence of foraging habitat associations using post-hoc "use-encounter" models. Results: Both species exhibited nested broad-scale and focussed ARS. Accounting for scale resulted in increases of up to 25% and 46% in inferred ARS for grey and harbour seals respectively. The prevalence and habitat associations of different ARS scales varied in a regional species-specific manner. Conclusions: We demonstrate the first application of HMMs to capture multi-scale ARS from animal-borne tracking data. Overlooking scale-dependence may mask individual variation and underestimate ARS, with consequences for ecological understanding and conservation applications. We hypothesise that seals employ different search scales for different habitats, competition levels and/or prey types. We call for further research to elucidate the prevalence and ecological significance of this phenomenon in other aquatic predators. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Abstract: | Context: Theoretical research has considered how animals should optimise foraging strategies to maximise fitness, adapting search scale to exploit different habitats and minimise competition. Empirical studies have described multi-scale area-restricted search (ARS) strategies for some species, but the physical and biological mechanisms underpinning such behaviour are rarely studied. Objectives: Our objectives were to quantify the presence, prevalence, and habitat associations of scale-dependent foraging for two sympatric seal species, accounting for regional variation across the seascape. Methods: We analyse a GPS telemetry dataset of 116 grey (Halichoerus grypus) and 325 harbour seals (Phoca vitulina) tracked throughout the North Sea. We test the existence of multi-scale ARS, comparing hidden Markov models (HMMs) with two ARS states against more conventional HMMs (one ARS state). We quantify regional variation and examine the scale-dependence of foraging habitat associations using post-hoc "use-encounter" models. Results: Both species exhibited nested broad-scale and focussed ARS. Accounting for scale resulted in increases of up to 25% and 46% in inferred ARS for grey and harbour seals respectively. The prevalence and habitat associations of different ARS scales varied in a regional species-specific manner. Conclusions: We demonstrate the first application of HMMs to capture multi-scale ARS from animal-borne tracking data. Overlooking scale-dependence may mask individual variation and underestimate ARS, with consequences for ecological understanding and conservation applications. We hypothesise that seals employ different search scales for different habitats, competition levels and/or prey types. We call for further research to elucidate the prevalence and ecological significance of this phenomenon in other aquatic predators. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 09212973 |
| DOI: | 10.1007/s10980-025-02281-z |
