Key Questions in Marine Megafauna Movement Ecology

Hays, Graeme C.; Ferreira, Luciana C.; Sequeira, Ana M. M.; Meekan, Mark G.; Duarte, Carlos M.; Bailey, Helen; Bailleul, Frédéric; Bowen, W. Don; Caley, M. Julian; Costa, Daniel P.; Eguı́luz, Vı́ctor M.; Fossette, Sabrina; Friedlaender, Ari S.; Gales, Nick; Gleiss, Adrian C.; Gunn, John; Harcourt, Robert; Hazen, Elliott L.; Heithaus, Michael R.; Heupel, Michelle R.; Holland, Kim N.; Horning, Markus; Jonsen, Ian D.; Kooyman, Gerald L.; Lowe, Christopher G.; Madsen, Peter T.; Marsh, Helene; Phillips, Richard A.; Righton, David; Ropert‐Coudert, Yan; Sato, Katsufumi; Shaffer, Scott A.; Simpfendorfer, Colin A.; Sims, David; Skomal, Gregory B.; Takahashi, Akinori; Trathan, Philip N.; Wikelski, Martin; Womble, Jamie N.; Thums, Michele

doi:10.1016/j.tree.2016.02.015

Cited by 393 publications

(404 citation statements)

References 96 publications

(124 reference statements)

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“…By focussing our analyses on route fidelity movements, our research is directly relevant to positional orientation during migration, one of the greatest unknowns in animal navigation science (Gould, 2004). By considering a diverse suite of species and scientific disciplines, our research represents a direct response to growing calls for more integrative research on animal migration and navigation (Bowlin et al, 2010;Hays et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Route Fidelity during Marine Megafauna Migration

Horton

Hauser²,

Zerbini

et al. 2017

Front. Mar. Sci.

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The conservation and protection of marine megafauna require robust knowledge of where and when animals are located. Yet, our ability to predict animal distributions in space and time remains limited due to difficulties associated with studying elusive animals with large home ranges. The widespread deployment of satellite telemetry technology creates unprecedented opportunities to remotely monitor animal movements and to analyse the spatial and temporal trajectories of these movements from a variety of geophysical perspectives. Reproducible patterns in movement trajectories can help elucidate the potential mechanisms by which marine megafauna navigate across vast expanses of open-ocean. Here, we present an empirical analysis of humpback whale (Megaptera novaeangliae), great white shark (Carcharodon carcharias), and northern elephant seal (Mirounga angustirostris) satellite telemetry-derived route fidelity movements in magnetic and gravitational coordinates. Our analyses demonstrate that: (1) humpback whales, great white sharks and northern elephant seals are capable of performing route fidelity movements across millions of square kilometers of open ocean with a spatial accuracy of better than 150 km despite temporal separations as long as 7 years between individual movements; (2) route fidelity movements include significant (p < 0.05) periodicities that are comparable in duration to the lunar cycles and semi-cycles; (3) latitude and bedrock-dependent gravitational cues are stronger predictors of route fidelity movements than spherical magnetic coordinate cues when analyzed with respect to the temporally dependent moon illumination cycle. We further show that both route fidelity and non-route fidelity movement trajectories, for all three species, describe overlapping in-phase or antiphase sinusoids when individual movements are normalized to the gravitational acceleration present at migratory departure sites. Although these empirical results provide an inductive basis for the development of testable hypotheses and future research questions, they cannot be taken as evidence for causal relations between marine megafauna movement decisions and geophysical cues. Experiments Horton et al.Marine Megafauna Route Fidelity on model organisms with known sensitivities to gravity and magnetism, complemented by further empirical observation of free-ranging animals, are required to fully explore how animals use discrete, or potentially integrated, geophysical cues for orientation and navigation purposes.

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Section: Introductionmentioning

confidence: 99%

Route Fidelity during Marine Megafauna Migration

Horton

Hauser²,

Zerbini

et al. 2017

Front. Mar. Sci.

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“…Understanding ontogenetic development of space use in marine megafauna species is a key aspect of marine megafauna movement ecology (Hays et al, 2016). Burgeoning questions in this field include how megafauna movements vary over space and time, essential knowledge for spatial planning and conservation management (Block et al, 2011;Hays et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Burgeoning questions in this field include how megafauna movements vary over space and time, essential knowledge for spatial planning and conservation management (Block et al, 2011;Hays et al, 2016). Sea turtles are one such megafauna group which move ontogenetically, spending part of their life in a juvenile nursery habitat and then migrating to an adult foraging habitat.…”

Section: Introductionmentioning

confidence: 99%

Spatial Distribution and Residency of Green and Loggerhead Sea Turtles Using Coastal Reef Habitats in Southern Mozambique

et al. 2017

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Sea turtles spend the majority of their immature and adult lives in foraging grounds, yet few studies have examined their abundance and condition in these areas when compared to more accessible nesting beach habitats. Here, a 5-year dive log, photo-identification (photo-ID) and surface encounter datasets were used to investigate the abundance, individual movements and distribution of sea turtles along 40 km of coastal reefs in southern Mozambique. A generalized linear model (GLM) was constructed with turtle sightings as the response variable. Habitat type, year and day of the year, as well as underwater visibility, were significant predictors of turtle sightings. However, only 8% of the total variance was explained by the model, indicating that other variables have a significant influence on turtle movement and distribution. Photo-ID differentiated 22 individual green turtles Chelonia mydas and 42 loggerhead turtles Caretta caretta from 323 photo-ID encounters. A majority (64%) of the photos could be used to identify the individual. Although residency times of up to 1152 days were calculated for juvenile green turtles, a low overall resighting rate indicates that individual turtles either had large home ranges or were transient to the area. Surface encounter data revealed a preference for nearshore shallow waters and an increased abundance close to reef systems. Sea turtles' preferences for shallow, nearshore habitats are likely to increase the encounter risk with opportunistic and targeted artisanal fishers who catch sea turtles.

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“…New research avenues have therefore opened for using biologging data to study how movement patterns may be changing across time, including in response to environmental variation (Hays et al., 2016). Most studies that deploy tracking devices on animals, such as seabirds, are usually aimed at answering broad ecological questions about habitat use and foraging behavior in one or a few successive years, as opposed to describing patterns of movement across time frames longer than a decade (but see Bogdanova et al., 2014; Carneiro et al., 2016).…”

Section: Introductionmentioning

confidence: 99%

Changing measurements or changing movements? Sampling scale and movement model identifiability across generations of biologging technology

Johnson

Boersch‐Supan

Phillips

et al. 2017

Ecology and Evolution

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Animal movement patterns contribute to our understanding of variation in breeding success and survival of individuals, and the implications for population dynamics. Over time, sensor technology for measuring movement patterns has improved. Although older technologies may be rendered obsolete, the existing data are still valuable, especially if new and old data can be compared to test whether a behavior has changed over time. We used simulated data to assess the ability to quantify and correctly identify patterns of seabird flight lengths under observational regimes used in successive generations of wet/dry logging technology. Care must be taken when comparing data collected at differing timescales, even when using inference procedures that incorporate the observational process, as model selection and parameter estimation may be biased. In practice, comparisons may only be valid when degrading all data to match the lowest resolution in a set. Changes in tracking technology, such as the wet/dry loggers explored here, that lead to aggregation of measurements at different temporal scales make comparisons challenging. We therefore urge ecologists to use synthetic data to assess whether accurate parameter estimation is possible for models comparing disparate data sets before planning experiments and conducting analyses such as responses to environmental changes or the assessment of management actions.

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Key Questions in Marine Megafauna Movement Ecology

Cited by 393 publications

References 96 publications

Route Fidelity during Marine Megafauna Migration

Route Fidelity during Marine Megafauna Migration

Spatial Distribution and Residency of Green and Loggerhead Sea Turtles Using Coastal Reef Habitats in Southern Mozambique

Changing measurements or changing movements? Sampling scale and movement model identifiability across generations of biologging technology

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