Magnetoreception in fishes: the effect of magnetic pulses on orientation of juvenile Pacific salmon

Abstract

A variety of animals sense Earth's magnetic field and use it to guide movements over a wide range of spatial scales. Little is known, however, about the mechanisms that underlie magnetic field detection. Among teleost fish, growing evidence suggests that crystals of the mineral magnetite provide the physical basis of the magnetic sense. In this study, juvenile Chinook salmon (Oncorhynchus tshawytscha) were exposed to a brief but strong magnetic pulse capable of altering the magnetic dipole moment of biogenic magnetite. Orientation behaviour of pulsed fish and untreated control fish was then compared in a magnetic coil system under two conditions: (1) the local magnetic field and (2) a magnetic field that exists near the southern boundary of the natural oceanic range of Chinook salmon. In the local field, no significant difference existed between the orientation of the control and pulsed groups. By contrast, orientation of the two groups was significantly different in the magnetic field from the distant site. These results demonstrate that a magnetic pulse can alter the magnetic orientation behaviour of a fish and are consistent with the hypothesis that salmon have magnetitebased magnetoreception.

The early marine distribution of Atlantic salmon in the North‐east Atlantic: A genetically informed stock‐specific synthesis

“…Many aspects of the ocean environment conditions are spatial and temporally variable. However, some key aspects will have been relatively temporally and spatially stable over evolutionary time frames, of hundreds to thousands of generations, and provide a basis for adaptive evolution of migratory behaviour, facilitated by, for example, magnetoreception (Naisbett‐Jones et al., 2020; Putman et al., 2020) to target optimal marine habitat areas for migration and feeding. Furthermore, where such habitats occur in multiple areas, the potential exists for different phylogeographic groups to have different migratory pathways and destinations.…”

The discovery of the use of magnetic navigational information

“…How magnetic ‘map’ components are perceived in other animals is still unclear. Pulse-experiments with spiny lobsters and Chinook salmons, Oncorhynchus tshawytscha , are in agreement with receptors based on magnetite, but it is unclear to what extent their magnetic compass was likewise affected (Ernst and Lohmann 2016 ; Naisbett-Jones et al 2020 ).…”

Magnetosensation

“…With such assays, researchers can then ask, "what disrupts this magnetic orientation?" to investigate a wide-range of questions related to how the magnetic field is detected (Wiltschko et al 1998;Naisbett-Jones et al 2020), how is magnetic information integrated with other cues (Stapput et al 2010), and whether specific human activities inhibit the ability of animals to use magnetic information (Engles et al 2014;Klimley et al 2021). While conceptually straightforward, I would be remiss if I did not note that there are all sorts of ways to produce equivocal results from such experiments and, at the heart of clear findings is good experimental design, with wellcontrolled and appropriately paired treatments (Kirschvink et al 2010;Putman et al 2017).…”