Browsing by Author "Vieira, Manuel"
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- Boat noise affects meagre (Argyrosomus regius) hearing and vocal behaviourPublication . Vieira, Manuel; Beauchaud, Marilyn; Amorim, Maria Clara P; Fonseca, PauloAquatic noise has increased in last decades imposing new constraints on aquatic animals' acoustic communication. Meagre (Argyrosomus regius) produce loud choruses during the breeding season, likely facilitating aggregations and mating, and are thus amenable to being impacted by anthropogenic noise. We assessed the impact of boat noise on this species acoustic communication by: evaluating possible masking effects of boat noise on hearing using Auditory Evoked Potentials (AEP) and inspecting changes in chorus sound levels from free ranging fish upon boat passages. Our results point to a significant masking effect of anthropogenic noise since we observed a reduction of ca. 20 dB on the ability to discriminate conspecific calls when exposed to boat noise. Furthermore, we verified a reduction in chorus energy during ferryboat passages, a behavioural effect that might ultimately impact spawning. This study is one of few addressing the effects of boat noise by combining different methodologies both in the lab and with free ranging animals.
- Boat noise impacts Lusitanian toadfish breeding males and reproductive outcomePublication . Amorim, Maria Clara P; Vieira, Manuel; Meireles, Gabriela; Novais, Sara C; Lemos, Marco F.L.; Modesto, Teresa; Alves, Daniel; Zuazu, Ana; Lopes, Ana F.; Matos, André B.; Fonseca, Paulo J.Anthropogenic noise is a growing threat to marine organisms, including fish. Yet very few studies have addressed the impact of anthropogenic noise on fish reproduction, especially in situ. In this study, we investigated the impacts of boat noise exposure in the reproductive success of wild Lusitanian toadfish (Halobatrachus didactylus), a species that relies on advertisement calls for mate attraction, using behavioural, physiological and reproductive endpoints. Two sets of artificial nests were deployed in the Tagus estuary and exposed to either ambient sound or boat noise during their breeding season. Toadfish males spontaneously used these nests to breed. We inspected nests for occupation and the presence of eggs in six spring low tides (in two years) and assessed male vocal activity and stress responses. Boat noise did not affect nest occupation by males but impacted reproductive success by decreasing the likelihood of receiving eggs, decreasing the number of live eggs and increasing the number of dead eggs, compared to control males. Treatment males also showed depressed vocal activity and slightly higher cortisol levels. The assessment of oxidative stress and energy metabolism-related biomarkers revealed no oxidative damage in noise exposed males despite having lower antioxidant responses and pointed towards a decrease in the activity levels of energy metabolism-related biomarkers. These results suggest that males exposed to boat noise depressed their metabolism and their activity (such as parental care and mate attraction) to cope with an acoustic stressor, consistent with a freezing defensive response/behaviour. Together, our study demonstrates that boat noise has severe impacts on reproductive fitness in Lusitanian toadfish. We argue that, at least fishes that cannot easily avoid noise sources due to their dependence on specific spawning sites, may incur in significant direct fitness costs due to chronic noise exposure.
- Call recognition and individual identification of fish vocalizations based on automatic speech recognition: An example with the Lusitanian toadfishPublication . Vieira, Manuel; Fonseca, Paulo Jorge; Amorim, Maria Clara Pessoa; Teixeira, Carlos J. C.The study of acoustic communication in animals often requires not only the recognition of species specific acoustic signals but also the identification of individual subjects, all in a complex acoustic background. Moreover, when very long recordings are to be analyzed, automatic recognition and identification processes are invaluable tools to extract the relevant biological information. A pattern recognition methodology based on hidden Markov models is presented inspired by successful results obtained in the most widely known and complex acoustical communication signal: human speech. This methodology was applied here for the first time to the detection and recognition of fish acoustic signals, specifically in a stream of round-the-clock recordings of Lusitanian toadfish (Halobatrachus didactylus) in their natural estuarine habitat. The results show that this methodology is able not only to detect the mating sounds (boatwhistles) but also to identify individual male toadfish, reaching an identification rate of ca. 95%. Moreover this method also proved to be a powerful tool to assess signal durations in large data sets. However, the system failed in recognizing other sound types.
- Detection of invasive fish species with passive acoustics: Discriminating between native and non-indigenous sciaenidsPublication . Amorim, Maria Clara P; Wanjala, Joan A.; Vieira, Manuel; Bolgan, Marta; Connaughton, Martin A.; Pereira, Beatriz P.; Fonseca, Paulo J.; Ribeiro, FilipeInvasive alien species have been rising exponentially in the last decades impacting biodiversity and ecosystem functioning. The soniferous weakfish, Cynoscion regalis, is a recent invasive sciaenid species in the Iberian Peninsula and was first reported in the Tagus estuary in 2015. There is concern about its possible impacts on native species, namely the confamiliar meagre, Argyrosomus regius, as there is overlap in their feeding regime, habitat use, and breeding behaviour. Here, we characterised the sciaenid-like sounds recently recorded in the Tagus estuary and showed that they are made by weakfish as they have similar numbers of pulses and pulse periods to the sounds made by captive breeding weakfish. We further demonstrate that breeding grunts from weakfish and the native sciaenid, recorded either in captivity or Tagus estuary, differ markedly in sound duration, number of pulses and pulse period in the two species, but overlap in their spectral features. Importantly, these differences are easily detected through visual and aural inspections of the recordings, making acoustic recognition easy even for the non-trained person. We propose that passive acoustic monitoring can be a cost-effective tool for in situ mapping of weakfish outside its natural distribution and an invaluable tool for early detection and to monitor its expansion.
- Fish sounds and boat noise are prominent soundscape contributors in an urban European estuaryPublication . Vieira, Manuel; Fonseca, Paulo; Amorim, Maria Clara PPassive acoustic monitoring is a valuable tool for non-intrusive monitoring of marine environments, also allowing the assessment of underwater noise that can negatively affect marine organisms. Here we provide for the first time, an assessment of noise levels and temporal soundscape patterns for a European estuary. We used several eco-acoustics methodologies to characterize the data collected over six weeks within May 2016 - July 2017 from Tagus estuary. Biophony was the major contributor dominated by fish vocalizations and the main driver for seasonal patterns. Maritime traffic was the major source of anthropogenic noise, with daily patterns monitored using 1584 Hz third-octave band level. This indicator avoided biophony and geophony, unlike other indicators proposed for the EU Marine Strategy Framework Directive. Furthermore, the frequency overlap between anthropophony and biophony demands precautionary actions and calls for further research. This study provides an assessment that will be useful for future monitoring and management strategies.
- Impact of anthropogenic noise on the survival and development of meagre (Argyrosomus regius) early life stagesPublication . Trabulo, Rita; Amorim, Clara; Fonseca, Paulo J.; Vieira, Manuel; Matos, André B.; Marin-Cudraz, Thibaut; Lemos, Marco F.L.; Moutinho, Ariana B.; Novais, Sara C; Pousão-Ferreira, Pedro; Candeias-Mendes, Ana; Faria, Ana MargaridaThe growth of human populations has been driving an unprecedent and widespread increase in marine traffic, posing a real threat to marine biodiversity. Even though we are now aware of the negative effects of shipping noise exposure on fish, information about the impact on their early life stages continues to lack. Meagre (Argyrosomus regius) is a vocal fish that uses estuaries with high levels of anthropogenic noise pollution as both breeding areas and nurseries. Here, the effects of boat noise exposure on the development and survival of meagre larvae were studied. Embryos and larvae were exposed to either noise (boat noise playback) or control treatments (coils producing a similar electric field to the speakers) and hatching rate, survival rate, morphometric traits and stress-related biomarkers, at hatching and at 2 days-post-hatching (dph) were analyzed. Results showed no conclusive effects of the impact of boat noise playback, even though there was an increased lipid droplet consumption and a decrease in body depth at 2dph larvae under this stressor. The assessment of oxidative stress and energy metabolism-related biomarkers at hatching showed a marginal decrease in superoxide dismutase (SOD) activity and no changes in DNA damage or electron transport system activity (ETS), although it cannot be disregarded that those effects could only be visible at later stages of larval development. Whether these morphological and developmental results have implications in later stages remains to be investigated. Further studies with longer exposure and wild meagre could help deepen this knowledge and provide a better understanding of how anthropogenic noise can impact meagre early stages
- Sound production in the Meagre, Argyrosomus regius (Asso, 1801): intraspecific variability associated with size, sex and contextPublication . Pereira, David; Vieira, Manuel; Pousão-Ferreira, Pedro; Candeias-Mendes, Ana; Barata, Marisa; Fonseca, Paulo; Amorim, Maria Clara PessoaMany fish taxa produce sound in voluntary and in disturbance contexts but information on the full acoustic repertoire is lacking for most species. Yet, this knowledge is critical to enable monitoring fish populations in nature through acoustic monitoring.
- Vocal rhythms in nesting Lusitanian toadfish, Halobatrachus didactylusPublication . Vieira, Manuel; Amorim, Maria Clara P; Fonseca, PauloMales 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.