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Browsing by Author "Pereira, Beatriz Palinhos"

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  • Acoustic repertoire of the meagre Argyrosomus regius: (Asso 1801): the influence of development, gender and context in temporal and spectral variation of calls
    Publication . Pereira, Beatriz Palinhos; Amorim, Maria Clara Correia de Freitas Pessoa de; Modesto, Teresa
    Sciaenids are among the largest families of vocal sonic fishes. The meagre (Argyrosomus regius, Asso 1801) was shown to emit sounds during the spawning season, but there is a lack of information on its wider vocal repertoire. The aims of this study were (1) to compare spontaneous sounds and distress calls recorded in captivity from juveniles and adults, and from female and male adults, (2) to describe seasonal variation in the sound production of A.regius (3) to characterize the acoustic activity and the sounds produced during social contexts in relation with spawning events (monitored by the collection of eggs from the tanks), and (4) to compare sounds recorded in captivity with sounds recorded in nature to validate ongoing passive acoustic monitoring carried out in Tagus estuary. Sound recordings were obtained from a group of adult breeders and juvenile meagre, A. regius, hosted at the aquaculture facilities of Instituto Português do Mar e da Atmosfera – Estação Piloto de Piscicultura de Olhão (IPMA – EPPO), Portugal. The present dataset demonstrates for the first time that in A. regius dominant frequency has an inverse relationship with fish size, that females emit sounds that differ from those of males and that sounds vary according to context and throughout ontogeny. Sounds produced by this species during the breading season showed a richer repertoire than previously observed by Lagardère and Mariani (2006), with meagre producing not two, but six call types. Additionally, besides the dense choruses of grunts already known for this species, meagre emitted successive series of isolated pulses, audible as ‘knocks’, as an acoustic signal related to spawning events. A seasonal trend was noted in knocking sounds but not in drumming due to the short study period. Captive meagre produced sounds which vary in their characteristics as reproduction proceeded, with acoustic parameters of sounds being significantly different among pre-spawning, spawning and post-spawning periods. Finally, sounds produced by meagre in captivity and in the Tagus estuary showed significant differences, probably associated with disparities between the environment and between individuals (i.e. temperature fluctuations in the field; larger size of wild individuals). The study of distress and social calls produced in captivity by A. regius will contribute to monitor natural populations of meagre including identify the presence and location of juveniles and breeding adults in nature.
    2019-02-26Master thesis Open access Show more