Multi-Decadal Humpback Whale Migratory Route Fidelity Despite Oceanographic and Geomagnetic Change

Horton, Travis W.; Zerbini, Alexandre N.; Andriolo, Artur; Danilewicz, Daniel; Sucunza, Federico

doi:10.3389/fmars.2020.00414

Cited by 37 publications

(38 citation statements)

References 60 publications

(93 reference statements)

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“…For example, many migratory taxa respond to environmental information over a range of timescales, including both proximate conditions resulting from short‐term environmental variability (Boustany et al 2010, Aikens et al 2017, Snyder et al 2017) as well as long‐term historical (i.e. climatological) conditions (Abrahms et al 2019a, Tsalyuk et al 2019, Horton et al 2020). Indeed, considering fine‐scale environmental variability (Hazen et al 2018, Morán‐Ordóñez et al 2018, Abrahms et al 2019b) or seasonal to inter‐annual environmental variability (Zimmermann et al 2009, Reside et al 2010, Descamps et al 2015, Thorson 2019) can improve predictions of species spatial distributions in response to environmental change.…”

Section: Introductionmentioning

confidence: 99%

Exploring timescales of predictability in species distributions

et al. 2021

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Accurate forecasts of how animals respond to climate-driven environmental change are needed to prepare for future redistributions, however, it is unclear which temporal scales of environmental variability give rise to predictability of species distributions. We examined the temporal scales of environmental variability that best predicted spatial abundance of a marine predator, swordfish Xiphias gladius, in the California Current. To understand which temporal scales of environmental variability provide biological predictability, we decomposed physical variables into three components: a monthly climatology (long-term average), a low frequency component representing interannual variability, and a high frequency (sub-annual) component that captures ephemeral features. We then assessed each component's contribution to predictive skill for spatially-explicit swordfish catch. The monthly climatology was the primary source of predictability in swordfish spatial catch, reflecting the spatial distribution associated with seasonal movements in this region. Importantly, we found that the low frequency component (capturing interannual variability) provided significant skill in predicting anomalous swordfish distribution and catch, which the monthly climatology cannot. The addition of the high frequency component added only minor improvement in predictability. By examining models' ability to predict species distribution anomalies, we assess the models in a way that is consistent with the goal of distribution forecasts -to predict deviations of species distributions from their average historical locations. The critical importance of low frequency climate variability in describing anomalous swordfish distributions and catch matches the target timescales of physical climate forecasts, suggesting potential for skillful ecological forecasts of swordfish distributions across short (seasonal) and long (climate) timescales. Understanding sources of prediction skill for species environmental responses gives confidence in our ability to accurately predict species distributions and abundance, and to know which responses are likely less predictable, under future climate change. This is important as climate change continues to cause an unprecedented redistribution of life on Earth.

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Section: Introductionmentioning

confidence: 99%

Exploring timescales of predictability in species distributions

et al. 2021

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“…The topography of the local magnetic field is used as a map, with the whales generally moving parallel to the contours. Geomagnetic field can provide a great deal of stable positional and directional information (Horton et al 2020).…”

Section: Resultsmentioning

confidence: 99%

Underlying environmental factors and geomagnetic fields linked to 45 pilot whalesGlobicephala macrorhynchusstranding in Modung white beach, Indonesian coast on 19^thFebruary 2021

2021

Preprint

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The reason whale and dolphin stranding is not fully understood and it is not linked to a standalone variable. Theories assume intertwined factors including sickness, underwater noise, navigational error, geographical features, the presence of predators, poisoning from pollution or algal blooms, geomagnetic field, and extreme weather are responsible to whale stranding. On 19th February 2021, a pod consists of 45 pilot whales Globicephala macrorhynchus was stranded in a remote 7050 m2 Modung white beach of Indonesian coast. This paper aims to assess the environmental factors that may be can explain and link to this stranding cases. Those factors include bathymetry, plankton cell density measured using MODIS, water sediment load measured using Sentinel 2 Bands 4,3,1, vessel traffic, precipitation (inch) and thunder (CAPE index J/kg), water salinity and temperature, and geomagnetic field (nT). The results show the water near stranding sites were shallow, has sediment load, high plankton density, warmer, receiving torrential rain prior stranding, having weak geomagnetic field and high total magnetic field change/year. The combination of those environmental covariates may influence the behavior, navigation, and echolocation of the said stranded pilot whale.

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“…However, historic whaling records and more than 15 years of satellite‐derived data have shown that humpback whale migrations in the southwest Atlantic have not changed during dynamic oceanographic and geomagnetic conditions (Horton et al, 2020). Furthermore, Abrahms et al (2019) found that both long‐term memory and resource tracking play vital roles in blue whale migrations, suggesting that other highly migratory species may struggle to adapt to climate change.…”

Section: Discussionmentioning

confidence: 99%

Decadal shift in foraging strategy of a migratory southern ocean predator

Berg

Vermeulen

Valenzuela

et al. 2020

Global Change Biology

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Rapid anthropogenic environmental change is expected to impact a host of ecological parameters in Southern Ocean ecosystems. Of critical concern are the consequences of these changes on the range of species that show fidelity to migratory destinations, as philopatry is hypothesized to help or hinder adaptation to climate change depending on the circumstances. Many baleen whales show philopatry to feeding grounds and are also capital breeders that meet migratory and reproductive costs through seasonal energy intake. Southern right whales (Eubalaena australis, SRWs) are capital breeders that have a strong relationship between reproductive output and foraging success. The population dynamics of South Africa's population of SRWs are characterized by two distinct periods: the 1990s, a period of high calving rates; and the late 2010s, a period associated with lowered calving rates. Here we use analyses of stable carbon (δ13C) and nitrogen (δ15N) isotope values from SRW biopsy samples (n = 122) collected during these two distinct periods to investigate foraging ecology of the South African population of SRWs over a time period coincident with the demographic shift. We show that South African SRWs underwent a dramatic northward shift, and diversification, in foraging strategy from 1990s to 2010s. Bayesian mixing model results suggest that during the 1990s, South African SRWs foraged on prey isotopically similar to South Georgia/Islas Georgias del Sur krill. In contrast, in the 2010s, South African SRWs foraged on prey isotopically consistent with the waters of the Subtropical Convergence, Polar Front and Marion Island. We hypothesize that this shift represents a response to changes in preferred habitat or prey, for example, the decrease in abundance and southward range contraction of Antarctic krill. By linking reproductive decline to changing foraging strategies for the first time in SRWs, we show that altering foraging strategies may not be sufficient to adapt to a changing ocean.

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Multi-Decadal Humpback Whale Migratory Route Fidelity Despite Oceanographic and Geomagnetic Change

Cited by 37 publications

References 60 publications

Exploring timescales of predictability in species distributions

Exploring timescales of predictability in species distributions

Underlying environmental factors and geomagnetic fields linked to 45 pilot whalesGlobicephala macrorhynchusstranding in Modung white beach, Indonesian coast on 19^thFebruary 2021

Decadal shift in foraging strategy of a migratory southern ocean predator

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Multi-Decadal Humpback Whale Migratory Route Fidelity Despite Oceanographic and Geomagnetic Change

Cited by 37 publications

References 60 publications

Exploring timescales of predictability in species distributions

Exploring timescales of predictability in species distributions

Underlying environmental factors and geomagnetic fields linked to 45 pilot whalesGlobicephala macrorhynchusstranding in Modung white beach, Indonesian coast on 19thFebruary 2021

Decadal shift in foraging strategy of a migratory southern ocean predator

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Underlying environmental factors and geomagnetic fields linked to 45 pilot whalesGlobicephala macrorhynchusstranding in Modung white beach, Indonesian coast on 19^thFebruary 2021