Sympatric Seals, Satellite Tracking and Protected Areas: Habitat-Based Distribution Estimates for Conservation and Management

• Published in: Frontiers in Marine Science
• Main Authors: Matt I. D. Carter, Lars Boehme, Michelle A. Cronin, Callan D. Duck, W. James Grecian, Gordon D. Hastie, Mark Jessopp, Jason Matthiopoulos, Bernie J. McConnell, David L. Miller, Chris D. Morris, Simon E. W. Moss, Dave Thompson, Paul M. Thompson, Debbie J. F. Russell
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2022
• Subjects: animal-borne telemetry; marine spatial planning (MSP); marine vertebrate predators; regional habitat preference; partial migration; place-based conservation; Science; Q; General. Including nature conservation; geographical distribution; QH1-199.5; North Atlantic; Phoca vitulina
• Online Access: https://doi.org/10.3389/fmars.2022.875869; https://doaj.org/article/59dc8c1604604f89aee2763a203e76bc

Marine predator populations are crucial to the structure and functioning of ecosystems. Like many predator taxa, pinnipeds face an increasingly complex array of natural and anthropogenic threats. Understanding the relationship between at-sea processes and trends in abundance at land-based monitoring sites requires robust estimates of at-sea distribution, often on multi-region scales. Such an understanding is critical for effective conservation management, but estimates are often limited in spatial extent by spatial coverage of animal-borne tracking data. Grey (Halichoerus grypus) and harbour seals (Phoca vitulina) are sympatric predators in North Atlantic shelf seas. The United Kingdom (UK) and Ireland represents an important population centre for both species, and Special Areas of Conservation (SACs) are designated for their monitoring and protection. Here we use an extensive high-resolution GPS tracking dataset, unprecedented in both size (114 grey and 239 harbour seals) and spatial coverage, to model habitat preference and generate at-sea distribution estimates for the entire UK and Ireland populations of both species. We found regional differences in environmental drivers of distribution for both species which likely relate to regional variation in diet and population trends. Moreover, we provide SAC-specific estimates of at-sea distribution for use in marine spatial planning, demonstrating that hotspots of at-sea density in UK and Ireland-wide maps cannot always be apportioned to the nearest SAC. We show that for grey seals, colonial capital breeders, there is a mismatch between SACs (where impacts are likely to be detected) and areas where impacts are most likely to occur (at sea). We highlight an urgent need for further research to elucidate the links between at-sea distribution during the foraging season and population trends observed in SACs. More generally, we highlight that the potential for such a disconnect needs to be considered when designating and managing protected sites, particularly for ...