Skip to content

Research at St Andrews

The diet of harbour and grey seals around Britain: examining the role of prey as a potential cause of harbour seal declines

Research output: Contribution to journalArticle

DOI

Open Access Status

  • Embargoed (until 6/09/20)

Abstract

1. Harbour seal populations have declined over the last 20 years in some regions around Britain. Causes are unknown but could include a reduction in prey availability which may potentially be influenced by competition with grey seals. The diets of these two marine predators overlap considerably, indicating that there could potentially be competition for prey.
2. In this study, the diets of harbour and grey seals in 2010/2012 were compared regionally and seasonally in relation to: (a) regional variation in population trends around Britain; (b) previous information on diet; and (c) changes in the stock size of key prey to investigate whether or not patterns could be consistent with reduction in prey availability or competition.
3. Diet was estimated from comprehensive sampling of scats around Scotland and eastern England. In total, 65,534 otoliths and beaks were recovered from 1976 harbour seal scats and 68,465 otoliths and beaks were recovered from 2205 grey seal scats collected in 2010/2012. Results showed considerable seasonal and regional variability; overall, sandeel and large gadids were the two main prey types.
4. Patterns in diet and trends in seal population size and prey stock size indicate that harbour seals have declined in regions where they appear to be reliant on sandeel and where sandeel stocks have declined, but not in regions where sandeel have never been an important component of the diet. A possible contributing reason for the harbour seal declines may therefore be a reduction in the availability of sandeel in these regions.
5. Sandeel continue to be an important (although reduced) prey in the diet of grey seals in regions where harbour seals have declined. If sandeel are a limiting resource, it is possible, therefore, that grey seals may reduce prey availability to harbour seals and contribute to their decline through competition.
Close

Details

Original languageEnglish
Pages (from-to)71-85
JournalAquatic Conservation: Marine and Freshwater Ecosystems
Volume29
Issue numberS1
Early online date6 Sep 2019
DOIs
Publication statusPublished - 6 Sep 2019

    Research areas

  • Behaviour, Coastal, Feeding, Mammals, Ocean, Predation, Sea loch

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Changing distribution of the east coast of Scotland bottlenose dolphin population and the challenges of area-based management

    Arso Civil, M., Quick, N. J., Cheney, B., Pirotta, E., Thompson, P. M. & Hammond, P. S., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 178-196 19 p.

    Research output: Contribution to journalArticle

  2. Fine-scale habitat partitioning of Chilean and Peale’s dolphins and their overlap with aquaculture

    Heinrich, S., Genov, T., Fuentes Riquelme, M. & Hammond, P. S., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 212-226

    Research output: Contribution to journalArticle

  3. Site fidelity and movement patterns of short-finned pilot whales within the Canary Islands: evidence for resident and transient populations

    Servidio, A., Pérez-Gil, E., Pérez-Gil, M., Cañadas, A., Hammond, P. S. & Martín, V., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 227-241

    Research output: Contribution to journalArticle

  4. The effect of a multi-target protocol on cetacean detection and abundance estimation in aerial surveys

    Lambert, C., Authier, M., Dorémus, G., Gilles, A., Hammond, P., Laran, S., Ricart, A., Ridoux, V., Scheidat, M., Spitz, J. & Van Canneyt, O., 4 Sep 2019, In : Royal Society Open Science. 6, 9, 17 p., 190296.

    Research output: Contribution to journalArticle

  5. Spatio-temporal patterns in fin whale (Balaenoptera physalus) habitat use in the northern Gulf of St. Lawrence

    Schleimer, A. C. H., Ramp, C., Plourde, S., Lehoux, C., Sears, R. & Hammond, P. S., 30 Jul 2019, In : Marine Ecology Progress Series. 623, p. 221-234

    Research output: Contribution to journalArticle

Related by journal

  1. Age–length relationships in UK harbour seals during a period of population decline

    Hall, A. J., Mackey, B., Kershaw, J. L. & Thompson, P., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 61-70 10 p.

    Research output: Contribution to journalArticle

  2. Automated detection and tracking of marine mammals: a novel sonar tool for monitoring effects of marine industry

    Hastie, G. D., Wu, G-M., Moss, S., Jepp, P., MacAulay, J. D. J., Lee, A., Sparling, C. E., Evers, C. H. M. & Gillespie, D. M., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 119-130

    Research output: Contribution to journalArticle

  3. Changing distribution of the east coast of Scotland bottlenose dolphin population and the challenges of area-based management

    Arso Civil, M., Quick, N. J., Cheney, B., Pirotta, E., Thompson, P. M. & Hammond, P. S., 6 Sep 2019, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 29, S1, p. 178-196 19 p.

    Research output: Contribution to journalArticle

Related by journal

  1. Aquatic Conservation: Marine and Freshwater Ecosystems (Journal)

    Monica Arso Civil (Reviewer)
    Jul 2018 → …

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

ID: 255392094

Top