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Projeto de investigação
Impact of anthropogenic noise on fish fitness
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Passive acoustic monitoring for assessment of natural and anthropogenic sound sources in the marine environment using automatic recognition
Publication . Vieira, Manuel; Fonseca, Paulo J.; Amorim, Maria Clara P.
In the marine environment, sound can be an efficient source of information. Indeed, several marine species, including fish, use sound to navigate, select habitats, detect predators and prey, and to attract mates. Therefore, all the abiotic, biotic and manmade sounds that comprise the soundscape, have the potential to be used to assess and monitor species and marine environments. Passive acoustic monitoring (PAM) involves the use of acoustic sensors to record sound in the environment, from which relevant ecological information can be inferred. This thesis studied marine soundscapes, with special attention on fish communities, anthropogenic noise, and applied several methods to analyse acoustic recordings. Most of the focus was on the Tagus estuary, where the presence of two highly vocal species is known: the Lusitanian toadfish (Halobatrachus didactylus) and the meagre (Argyrosomus regius). Azorean and Mozambique soundscapes were also analysed. Several methods were applied to extract information and to visualize soundscape characteristics, including sound recognition systems based on hidden Markov models to recognize fish sounds and boat passages. Analysis of several types of marine environments and time scales showed several advantages and disadvantages of different methods. The use of sound pressure level on different frequency bands allowed the quantification of daily and seasonal patterns. Ecoacoustic indices appear to be cost-effective tools to monitor biodiversity in some marine environments. Using automatic recognition, vocal rhythms (diel and seasonal patterns) and vocal interactions among individuals were also characterized. Furthermore, boat noise effects on fish were studied: we encountered impacts on the audition, vocal behaviour and reproduction. Overall, we used PAM as a tool to remotely assess and monitor soundscapes, biodiversity, fish communities’ seasonal patterns, fish behaviour, species presence, and the effect of anthropogenic noise aiming to contribute for the management and conservation of marine ecosystems.
Correction: Boat noise interferes with Lusitanian toadfish acoustic communication
Publication . Alves, Daniel; Vieira, Manuel; Amorim, M. Clara P.; Fonseca, Paulo
Anthropogenic noise is considered a major underwater pollutant as
increasing ocean background noise due to human activities is
impacting aquatic organisms. One of the most prevalent
anthropogenic sounds is boat noise. Although motorboat traffic has
increased in the past few decades, its impact on the communication of
fish is still poorly known. The highly vocal Lusitanian toadfish
(Halobatrachus didactylus) is an excellent model to test the impact of
this anthropogenic stressor as it relies on acoustic communication to
attractmates.Here,we performed two experiments to test the impact of
boat noise on the acoustic communication of the Lusitanian toadfish.
Using the auditory evoked potential (AEP) technique, we first
compared the maximum distance a fish can perceive a boatwhistle
(BW), the mate attraction acoustic signal, before and after embedding it
in boat noise. Noises from a small motorboat and from a ferryboat
reduced the active space from a control value of 6.4–10.4 m to
2.0–2.5 m and 6.3–6.7 m, respectively. In the second experiment we
monitored the acoustic behaviour of breeding males exposed to boat
noise playbacks and we observed an increase in the inter-onset
interval ofBWs and a disruption of the usual vocal interactions between
singing males. These results demonstrate that boat noise can severely
reduce the acoustic active space and affect the chorusing behaviour in
this species, which may have consequences in breeding success for
individuals and could thus affect fitness.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
9471 - RIDTI
Número da atribuição
PTDC/BIA-BMA/29662/2017