[MARMAM] New paper: Grey seals - relationship between breeding and foraging regions

debbie russell djf.russell at gmail.com
Mon Jan 28 01:18:44 PST 2013


Hi all

We have a new paper in Journal of Applied Ecology linking foraging and
breeding regions in grey seals in the UK.  Please see below:

http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12048/abstract


Summary
1. The annual cycle of many animals is characterized by the need to satisfy
different life
history priorities, often requiring seasonal movements. For such species,
investigating carryover
effects (such as the year-long drivers of breeding success) and managing
protected areas
effectively, relies on quantifying these movements. Here, we model the
seasonal movements of
the UK population of grey seals *Halichoerus grypus* and show how insights
from the model
can improve its management.
2. We fit a hidden process model to two types of information – regional
population redistribution
and individual movements – to estimate the seasonal transition
probabilities of breeding
female grey seals among four regions around the UK.
3. We found that between 21% and 58% of females used different regions for
breeding and
foraging.
4. For our study period, we detected an increase in the breeding
performance of animals that
foraged in the Hebrides and South-East Coast.
5. Grey seal Special Areas of Conservation (SACs) were designed to
encompass a significant
proportion of the UK breeding population: ~ 40% of the breeding females in
our study area.
Of the females breeding on SACs, only 15% breed in Northern Scotland, but
up to 50% forage
there. Our results indicate that, by only considering the breeding
distribution of females
that breed in SACs, the impact of anthropogenic activities on nearby SACs
may be overestimated,
whereas impacts on remote SACs may be underestimated.
6. Synthesis and applications. By quantifying the link between the foraging
and breeding distributions
of grey seals, management of breeding populations can be focused on the
foraging
regions where the resources necessary for reproduction are acquired. The
construction of marine
developments is dependent on demonstrating that they will not have an
adverse effect on
the integrity of Special Areas of Conservation (SACs), and we have shown
that this requires
consideration of the seasonal transition probabilities estimated in this
study. Our specific
results provide support for management strategies that jointly consider
SACs and Marine
Protected Areas (MPAs). More generally, we prescribe combinations of data
on population
size, breeding performance and individual movement that can enable our
framework to be
applied to seasonally migrating species.

Key-words: Bayesian statistics, capital breeding, individually referenced
data, integrated
modelling, marine conservation, Markov Chain Monte Carlo, migration,
pinnipeds, site
fidelity, WinBUGS

Best wishes

Debbie


-- 
***********************************************
Dr Debbie Russell
Sea Mammal Research Unit (SMRU)
Centre for Research into Ecological and Environmental Monitoring (CREEM)

Office:       +44 (0)1334 467281
Tuesdays: +44 (0)1334 461808
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Postal address:
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Gatty Marine Laboratory
University of St Andrews
St Andrews
Fife
KY16 8LB
UK

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