To investigate the ability of elasmobranchs to distinguish between differing prey-type electric fields we examined the electroreceptive foraging behaviour of a model species, Scyliorhinus canicula (small-spotted catshark). Catshark preferences were studied by behaviourally conditioning them to swim through narrow tunnels, and on exit presenting them simultaneously with two different electric fields. Their subsequent choices of the following paired options were recorded; (i) Two artificial electric fields (dipole electrodes) with different magnitude direct current (D.C.), (ii) Two artificial electric fields, one D.C. and the other alternating current (A.C.), of the same magnitude, and (iii) similar magnitude, natural and artificial D.C. electric fields associated with shore crabs and dipole electrodes respectively. We found a highly significant preference for the stronger D.C. electric field and a less pronounced, but still significant, preference for the A.C. electric field rather than the D.C. electric field. No preference was demonstrated between the artificial and natural D.C. electric fields. The findings are discussed in relation to the animal’s diet and ecology and with regard to anthropogenic sources of electric fields within their habitat.
Joel Kimber was supported by a Fisheries Society of the British Isles funded studentship and by Cranfield University. David Sims was supported by a Natural Environment Research Council (NERC) funded Marine Biological Association (MBA) Fellowship and by the NERC Oceans 2025 Strategic Research Programme (Theme 6 Science for Sustainable Marine Resources)
Location of Research
Laboratory Study, Marine Biological Association
We studied the preferences of a benthic elasmobranch, Scyliorhinus canicula (small-spotted catshark) for certain prey-type electric fields, thereby quantifying the fish’s ability to differentiate between rather than merely detect the presence of the fields. These electric fields comprised of various artificial (dipole) fields, known to be generally similar to those encountered by catsharks whilst foraging (rather than precise matches to specific prey species’ biofields), and biological fields (emitted by a prey species).
The authors found a highly significant preference for the stronger D.C. electric field and a less pronounced, but still significant, preference for the A.C. electric field rather than the D.C. electric field. No preference was demonstrated between the artificial and natural D.C. electric fields. The electroreceptive ability of individual elasmobranchs to discriminate and choose between potential prey, and between prey and artificial stimuli could ultimately affect an individual’s success and fitness via direct effects on somatic and gonadal growth. Electroreception may also enable these fish to recognise a number of other important signals: the risk associated with differing species and sizes of potential predators; different con-specifics (possible rivals or suitable mates); differing symbionts (such as mutualistic cleaning fish and shrimps as opposed to parasitic copepods and mimic cleaner fish); and to recognise movement paths (to reach feeding grounds, mating areas or refuges).
Kimber, J.; Sims, D.; Bellamy, P.; Gill, A. (2011). The ability of a benthic elasmobranch to discriminate between biological and artificial electric fields. Marine Biology, 158(1), 8.