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Publication
Vocal rhythms in nesting Lusitanian toadfish, Halobatrachus didactylus
Advisor(s)
Abstract(s)
Males of several fish species aggregate and vocalize together, increasing the detection range of the sounds and
their chances of mating. In the Lusitanian toadfish (Halobatrachus didactylus), breeding males build nests under
rocks in close proximity and produce hundreds of boatwhistles (BW) an hour to attract females to lay their
demersal eggs on their nests. Chorusing behaviour includes fine-scale interactions between individuals, a
behavioural dynamic worth investigating in this highly vocal fish. Here we present a study to further investigate
this species’ vocal temporal patterns on a fine (individual rhythms and male-male interactions) and large (chorus
daily patterns) scales. Several datasets recorded in the Tagus estuary were labelled with the support of an
automatic recognition system based on hidden Markov models. Fine-scale vocal temporal patterns exhibit high
variability between and within individuals, varying from an almost isochronous to an apparent aperiodic pattern.
When in a chorus, males exhibited alternation or synchrony calling patterns, possibly depending on motivation
and social context (mating or male-male competition). When engaged in sustained calling, males usually
alternated vocalizations with their close neighbours thus avoiding superposition of calls. Synchrony was
observed mostly in fish with lower mean calling rate. Interaction patterns were less obvious in more distanced
males. Daily choruses showed periods with several active calling males and periods of low activity with no
significant diel patterns in shallower intertidal waters. Here, chorusing activity was mainly affected by tide level.
In contrast, at a deeper location, although tidal currents causes a decrease in calling rate, tide level did not
significantly influence calling, and there was a higher calling rate at night. These data show that photoperiod and
tide levels can influence broad patterns of Lusitanian toadfish calling activity as in other shallow-water fishes,
but fine temporal patterns in acoustic interactions among nesting males is more complex than previously known
for fishes.
Description
Keywords
Acoustic interactions Fish acoustic communication Passive acoustic monitoring Effect of tide Batrachoididae
Citation
Vieira, M., Amorim, M.C.P., Fonseca, P. J.(2021), Vocal rhythms in nesting Lusitanian toadfish, Halobatrachus didactylus. Ecological informatics, 63, 1-15
Publisher
Elsevier