Marta Bolgan

Painted gobies sing their quality out loud: Acoustic rather than visual signals advertise male quality and contribute to mating success

Summary Females use multiple cues from different sensory modalities to choose males of high phenotypic or genetic quality to mate with. Fish may use visual and acoustic communication during mating, but few studies have associated multimodal signals with male quality and reproductive success. We examined whether visual and acoustic courtship signals reflect male quality and influence mating success in the painted goby (Pomatoschistus pictus), a highly visual and vocal fish species with paternal care. Painted gobies make conspicuous courtship visual displays such as body quivering and eight-shaped swimming patterns and two types of sounds: drums that are composed of a sequence of low-frequency pulses and a thump-like non-pulsed sound. We predicted that both sensory modalities would advertise male size and condition and influence mating success. We found that larger number of pulses in a drum, lower fatigue (where fatigue is the increase in pulse period during drum production) and higher drum absolute amplitude levels were good predictors of larger male size. Males with high condition factor (Fultons K) showed high drumming activity and low thumping and visual courtship levels. Drumming activity was a good predictor of male fat reserves. Males that succeeded to mate emitted sounds with higher number of pulses and longer pulse periods and showed higher drumming but lower thumping activity than unsuccessful males. All traits (except pulse period) reflected higher male Fultons K or fat reserves, suggesting that females are selecting for male condition. Neither male size nor visual courtship was apparently used in mate selection. Contrary to our expectations, females did not seem to prefer larger or vigorous visually displaying males but chose mates in better condition using multiple cues of drumming sounds. We suggest that preference for high mate condition is related to preference for increased parental ability and hatching success in species with paternal care. To the best of our knowledge, this is the first study that addresses the relative role of signals from different sensory modalities including acoustics, in advertising male quality and in contributing to reproductive success in fish.

The soundscape of Arctic charr spawning grounds in lotic and lentic environments: can passive acoustic monitoring be used to detect spawning activities?

Abstract The aims of this study were to (i) assess the efficacy of passive acoustic monitoring (PAM) for detecting Arctic Charr at their spawning grounds and (ii) characterize the overall acoustic soundscape of these sites. PAM was carried out over three Arctic Charr spawning grounds in the UK, one lotic and two lentic. 24-h cycles of recordings were collected prior to and during the Arctic Charr spawning season, which was determined from data returns by simultaneous net monitoring. Acoustic analysis consisted of manual quantification of sound sources, Acoustic Complexity Index (ACI) calculation and spectral analysis in 1/3 octave band (SPL; dB re 1 μPa). In the lotic spawning ground, prior to the beginning of Arctic Charr spawning, SPL and ACI showed a restricted range of variation throughout the 24-h, while during spawning the night values of SPL and ACI were found to significantly increase, concurrently with the rate of gravel noise induced by fish spawning activities and fish air passage sounds. Both prior to and during the Arctic Charr run, the lentic soundscape was characterized by diel variation due to the daytime presence of anthropogenic noise and the night-time presence of insect calls, while only a few occurrences of fish air passage sounds and gravel noise were recorded. These findings suggest that PAM over Arctic Charr spawning grounds could provide meaningful information to be used in developing management plans for this threatened species, such as determining the location and time of arrival, diel pattern and length of spawning activities.

Sound production by the Shi drum Umbrina cirrosa and comparison with the brown meagre Sciaena umbra: a passive acoustic monitoring perspective

Sounds produced by the Shi drum Umbrina cirrosa were short trains of pulses with an average pulse period of 180 ms, pulse duration of c. 40 ms and an average peak frequency of 400 Hz; average values of acoustical properties differed from those recorded from the brown meagre Sciaena umbra in previous studies. The present study provides a preliminary tool for discriminating between these two species while conducting passive acoustic monitoring. The potential effects of ontogeny on sound production in both species are discussed and recommendations are made for further research.

Does the Arctic charr Salvelinus alpinus produce sounds in a captive setting

Arctic charr Salvelinus alpinus did not appear to invest in acoustic communication during courtship and agonistic interactions in captivity. Salvelinus alpinus did, however, produce four different types of sounds which were found to be associated with three different types of air exchange behaviours which probably have a swimbladder regulation function. Since air passage sounds appear to be common among Salmonidae, it is suggested that the potential of passive acoustics techniques for behavioural and ecological monitoring should be further investigated in future field and laboratory investigations.

Differential investment in acoustic communication during social interactions in two closely-related sand goby species

Communication signals provide key information for conspecific recognition, mate choice and rival assessment. The painted goby Pomatoschistus pictus and the common goby P. microps are two closely-related sand goby species, often sympatric and with an overlapping breeding season. In this study we staged male–male and male–female interactions and compared visual, tactile and acoustic behaviour in both species. Sound production in the common goby is here accounted for the first time. We observed some differences in visual behaviour and a striking divergence in the use of tactile and acoustic communication during courtship and agonistic interactions. We further describe differences in drumming signals with social context in the painted goby. This study suggests a divergence in communication in two closely-related sand goby species and emphasizes the importance of further research concerning the role of multimodal communication in closely-related species.

Acoustic Complexity of vocal fish communities: a field and controlled validation

The Acoustic Complexity Index (ACI) is increasingly applied to the study of biodiversity in aquatic habitats. However, it remains unknown which types of acoustic information are highlighted by this index in underwater environments. This study explored the robustness of the ACI to fine variations in fish sound abundance (i.e. number of sounds) and sound diversity (i.e. number of sound types) in field recordings and controlled experiments. The ACI was found to be sensitive to variations in both sound abundance and sound diversity, making it difficult to discern between these variables. Furthermore, the ACI was strongly dependent on the settings used for its calculation (i.e. frequency and temporal resolution of the ACI algorithm, amplitude filter). Care should thus be taken when comparing ACI absolute values between studies, or between sites with site-specific characteristics (e.g. species diversity, fish vocal community composition). As the use of ecoacoustic indices presents a promising tool for the monitoring of vulnerable environments, methodological validations like those presented in this paper are of paramount importance in understanding which biologically important information can be gathered by applying acoustic indices to Passive Acoustic Monitoring data.

Behaviour of Arctic charr Salvelinus alpinus during an induced mating season in captivity: how male relative size influences male behavioural investment and female preference over time

The behaviour of sexually mature Arctic charr Salvelinus alpinus specimens (fifth farm generation) was observed in captivity for four consecutive days. Only agonistic interactions between males of different size were facilitated on the first 2 days, while both agonistic and courtship interactions were possible from the third day up to the end of the experiment. The reliability of behavioural analysis was assessed in order to reduce the possibility of observer errors within the generated datasets. The behavioural investment of big males, small males and females was analysed using general linear models (two-way repeated measures ANOVAs with time and male size as factors). A peak in the agonistic interactions between males occurred during the first day of interactions, where the agonistic investment of big males was significantly higher than that of small males. This resulted in an increased investment in submissive behaviour by the small males, who consistently performed submissive behaviours from the second day of interactions up to the end of the trial. Big males were found to invest significantly more than small males in courtship behaviours for the duration of the trial. Even though females performed inter-sexual behaviours towards both big and small males for the entire observation period, female interaction rate towards big males was higher than towards small males. This study suggests that both male investment in mating behaviour and female preference might be related to male characteristics such as body length and that S. alpinus behavioural patterns and mate choice cues might be strongly context-related and characterized by high levels of behavioural plasticity (i.e. presence-absence of certain behavioural units or potential reversal of a mate choice cue) within the same species. Finally, in light of this, some conservation measures are discussed. In particular, effective management plans should take into account the high level of behavioural plasticity likely to be occurring in this species.

The soundscape of a mussel farm: Biophony and man-made noise levels

During the summer of 2015, four Passive Acoustic Monitoring (PAM) surveys were carried out over a mussel farm in the Venetian (Italy) littoral zone at night-time hours. A qualitative and quantitative analysis of the soundscape was carried out. The high frequencies component of the soundscape (i.e above 2 kHz) was dominated by snapping shrimps sounds, while the low frequency component (i.e. below 2 kHz) was characterized by fish vocalization, mainly emitted by Sciaena umbra (Sciaenidae), with less frequent occurrences emitted by Gobidae spp. S. umbra highest vocal activity was recorded from June to August inside the mussel farm. The low frequency component of the soundscape was dominated by boat noise; in particular, low frequency noise (i.e. below 4 kHz) emitted by commercial ships and passenger cruises. The Acoustic Complexity Index (ACI) was found to increase concurrently with the number of S. umbra vocalizations: ACI highest values corresponded with S. umbra chorus recorded during July. The results of ...

Is the Venice Lagoon Noisy? First Passive Listening Monitoring of the Venice Lagoon: Possible Effects on the Typical Fish Community

Three passive listening surveys have been carried out in two of the three Venice lagoon tide inlets and inside the Venice island. The spectral content and the intensity level of the underwater noise as well as the presence or absence of Sciaena umbra and the distribution of its different sound patterns have been investigated in all the recording sites. The passive listening proved to be successful in detecting S. umbra drumming sounds in both Venice lagoon tide inlets. Our results indicate that the spectral content and the level of underwater noise pollution in the Venice lagoon could affect fish acoustic communication.

Acoustic Communication in Pomatoschistus spp.: A Comparison Between Closely Related Species

Many vertebrates, including teleosts, rely on acoustic signals for communication (Myrberg and Lugli 2006). Sound production has been documented in four species of sand gobies (Pomatoschistus). Males of the sand (P. minutus), marbled (P. marmoratus), and canestrini (P. canestrinii) gobies produce low-frequency pulsed sounds when females enter the nest (Lugli and Torricelli 1999). The male painted goby (P. pictus) also produces similar drumming sounds outside the nest during courtship (Amorim and Neves 2007). These drumming sounds present interspecific differences, suggesting that they could potentially be used in species-specific recognition (see Table 1).