The functional roles of passive electroreception in non-electric fishes

Abstract

Passive electroreception is a complex and specialised sense found in a large range of aquatic vertebrates primarily designed for the detection of weak bioelectric elds. Particular attention has traditionally focused on cartilaginous shes, but a range of teleost and non-teleost shes from a diversity of habitats have also been examined. As more species are investigated, it has become apparent that the role of electroreception in shes is not restricted to locating prey, but is utilised in other complex behaviours. This paper presents the various functional roles of passive electroreception in non-electric shes, by reviewing much of the recent research on the detection of prey in the context of differences in species' habitat (shallow water, deep-sea, freshwater and saltwater). A special case study on the distribution and neural groupings of ampullary organs in the omnihaline bull shark, Carcharhinus leucas, is also presented and reveals that prey-capture, rather than navigation, may be an important determinant of pore distribution. The discrimination between potential predators and conspeci cs and the role of bioelectric stimuli in social behaviour is discussed, as is the ability to migrate over short or long distances in order to locate environmentally favourable conditions. The various theories proposed regarding the importance and mediation of geomagnetic orientation by either an electroreceptive and/or a magnetite-based sensory system receives particular attention. The importance of electroreception to many species is emphasised by highlighting what still remains to be investigated, especially with respect to the physical, biochemical and neural properties of the ampullary organs and the signals that give rise to the large range of observed behaviours.

A test of the senses: Fish select novel habitats by responding to multiple cues

“…These stimuli vary in concentrations, gradients, and intensities on temporal and spatial scales throughout the seascape. Many taxa are known to use sensory information for short-and long-distance orientation (moving relative to the environment) and navigation (movement toward a goal), including whales (Walker et al 1992), turtles (Avens and Lohmann 2003), sharks (Collin and Whitehead 2004), salmonid fish (Dittman and Quinn 1996), reef fish (Myrberg and Fuiman 2002), and crabs (Radford et al 2007).…”

Laboratory Studies of the Effects of Static and Variable Magnetic Fields on Freshwater Fish

“…Other than the brief reactions by sturgeon to the variable fields reported here, no longer-term changes in behavior or mortalities were observed. Passive electroreception is widespread in fish, occurring in numerous orders of cartilaginous and nonteleost bony fishes (Collin and Whitehead 2004); this capability has not been reported for most teleosts (Wilkens and Hofmann 2005). Of the species we tested, paddlefish and members of the sturgeon and catfish families are known to be electrosensitive.…”

Effects on Freshwater Organisms of Magnetic Fields Associated with Hydrokinetic Turbines

“…Two species of Asian sturgeon have been reported to alter their behavior in changing electric fields (Basov 1999;2007). Other fish species (e.g., eels, cod, Atlantic salmon, catfish, paddlefish) will respond to induced voltage gradients associated with water movement and geomagnetic emissions (Collin and Whitehead 2004;Wilkens and Hofmann 2005), but their electrosensitivity does not appear to be based on the same mechanism as sharks (Gill et al 2005). …”