  Over the past few decades, magnetoreception has been discovered in several
species of teleost and elasmobranch fishes by employing varied experimental
methods including conditioning experiments, observations of alignment with
external fields, and experiments with magnetic deterrents. Biogenic magnetite
has been confirmed to be an important receptor mechanism in some species, but
there is ongoing debate regarding whether other mechanisms are at work. This
paper presents evidence for magnetoreception in three additional species, red
drum (Sciaenops ocellatus), black drum (Pogonias cromis), and sea catfish
(Ariopsis felis), by employing experiments to test whether fish respond
differently to bait on a magnetic hook than on a control. In red drum, the
control hook outcaught the magnetic hook by 32 - 18 for chi-squared = 3.92 and
a P-value of 0.048. Black drum showed a significant attraction for the magnetic
hook, which prevailed over the control hook by 11 - 3 for chi-squared = 4.57
and a P-value of 0.033. Gafftopsail catfish (Bagre marinus) showed no
preference with a 31 - 35 split between magnetic hook and control for
chi-squared = 0.242 and a P-value of 0.623. In a sample of 100 sea catfish in
an analogous experiment using smaller hooks, the control hook was preferred
62-38 for chi-squared = 5.76 and a P-value of < 0.001. Such a simple method for
identifying magnetoreceptive species may quickly expand the number of known
magnetoreceptive species and allow for easier access to magnetoreceptive
species and thus facilitate testing of magnetoreceptive hypotheses.
