10.5061/DRYAD.D0H7S
Miller, Peter I.
Plymouth Marine Laboratory
Scales, Kylie L.
University of California System
Plymouth Marine Laboratory
Ingram, Simon N.
Plymouth University
Southall, Emily J.
Marine Biological Association of the United Kingdom
Sims, David W.
Marine Biological Association of the United Kingdom
University of Southampton
Data from: Basking sharks and oceanographic fronts: quantifying
associations in the north-east Atlantic
Dryad
dataset
2016
animal tracking
marine vertebrate
marine megavertebrate
habitat preference
front mapping
2016-02-03T00:00:00Z
2016-02-03T00:00:00Z
en
https://doi.org/10.1111/1365-2435.12423
17946 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Understanding the mechanisms that link oceanographic processes and
marine vertebrate space use is critical to our knowledge of marine
ecosystem functioning, and for effective management of populations of
conservation concern. 2. The basking shark Cetorhinus maximus has been
observed in association with oceanographic fronts – physical interfaces at
the transitions between water masses – exploiting foraging opportunities
resulting from zooplankton aggregation. However, the scale, significance
and variability of these associations have not previously been
established. 3. Here, we quantify the influence of thermal and
chlorophyll-a fronts on basking shark habitat use in the north-east
Atlantic. We use animal-mounted archival tracking together with composite
front mapping via Earth Observation (EO) remote sensing to provide an
oceanographic context to shark movements. 4. We investigate levels of
association with fronts occurring over two spatio-temporal scales, (i)
broad-scale, seasonally persistent frontal zones and (ii) contemporaneous
thermal and chl-a fronts. Using random walk simulations and logistic
regression within an iterative generalized linear mixed modelling (GLMM)
framework, we find that seasonal front frequency is a significant
predictor of shark presence. 5. Oceanographic metrics time-matched to
shark tracks indicate that sharks show a preference for productive regions
and associate with contemporaneous thermal and chl-a fronts more
frequently than could be expected at random. Moreover, we highlight the
importance of front persistence and cross-frontal temperature step, which
appear to interact to affect the degree of prey aggregation along thermal
fronts in this shelf-sea system. 6. Our findings confirm that surface
frontal activity is a predictor of basking shark presence in the
north-east Atlantic, both over seasonal timescales and in near real-time.
These insights have clear implications for understanding the preferred
habitats of basking sharks in the context of anthropogenic threat
management and marine spatial planning in the region.
GLS tracking locations + time-matched front metricsAll original GLS
tracking locations, plus associated 7-day front thermal and chlorophyll-a
front metrics (Thermal metrics = thermal front density, Tdens5; thermal
front gradient density, Tgdens5; thermal front persistence, Tpfront;
distance to closest thermal front (km), Tdist; side of thermal front,
Tside; Chlorophyll-a metrics = chl-a front density, Cdens5; chl-a front
gradient density, Cgdens5; persistence of chl-a front, Cpfront; distance
to closest chl-a front, Cdist; side of chl-a front,
Cside).gls_metrics_MASTER.txt