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

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

doi:10.3389/fmars.2020.00414

Abstract

Understanding how organisms respond to environmental change is one of the most pressing grand challenges of organismal biology. In the vast oceans that cover 71% of Earth’s surface, remote sensing technologies have created unprecedented opportunities to create new knowledge and deliver integrated understandings of marine organism-environment interactions via long-term monitoring. Using historic whaling records and >15 years of satellite-derived data, we show that movement parameters associated with long-distance humpback whale migrations, including utilization of a south-southeast directed migratory corridor, migration path straightness, direction, timing and velocity, have not significantly changed during a period of dynamic oceanographic and geomagnetic conditions. These findings reveal an apparent paradox: humpback whale migrations do not change in a changing ocean. Geophysical analyses of the same humpback whale movements demonstrate that these whales maintained prolonged migratory fidelity to a limited suite of spatiotemporal trajectories through gravitational coordinates, raising the possibility that migratory decisions are relatively insensitive to changing oceanographic and geomagnetic conditions. Our findings highlight the importance of filling the knowledge-gaps that currently limit our ability to understand and anticipate organismal responses to rapidly changing Earth system conditions.

Highlights

Migratory animals face an uncertain future (Cotton, 2003; Wilcove and Wikelski, 2008; Hazen et al, 2013; Hof et al, 2017; Cohen et al, 2018)
The historic Soviet whaling and satellite telemetry data demonstrate that Southwest Atlantic humpback whales have utilized a spatially restricted ∼1.0 million km2 migratory corridor (i.e., south-southeast corridor (SSEC)) for >50 years (Figure 1)
The humpback whale migrations we report describe highly significant and reproducible sinusoidal gravitational coordinate (i.e., g-space) trajectories

Summary

Introduction

Migratory animals face an uncertain future (Cotton, 2003; Wilcove and Wikelski, 2008; Hazen et al, 2013; Hof et al, 2017; Cohen et al, 2018). Fidelity Trumps Change persist into the future requires knowledge of how migrants respond to Earth system dynamics (Schwenk et al, 2009; Bowlin et al, 2010). It is widely agreed that addressing the challenges inherent to a dynamic Earth system requires long-term monitoring delivered through integrated interdisciplinary research approaches (Schwenk et al, 2009; Bowlin et al, 2010; Hays et al, 2016; Urban et al, 2016; Miloslavich et al, 2018). The primary goal of this research was to explore gaps in our knowledge regarding how humpback whale (Megaptera novaeangliae) long-distance migrations respond to oceanographic and geomagnetic change through long-term remote ocean monitoring

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Results

Discussion

Conclusion