Localizing individual soniferous fish using passive acoustic monitoring

Abstract

Identifying where fish inhabit is a fundamentally important topic in ecology and management allowing acoustically sensitive times and areas to be prioritized. Passive acoustic localization has the benefit of being a non-invasive and non-destructive observational tool, and provides unbiased data on the position and movement of aquatic animals. This study used the time of arrival difference (TOAD) of sound recordings on a four-hydrophone array to pinpoint the location of male oyster toadfish, Opsanus tau, a sedentary fish that produces boatwhistles to attract females. Coupling the TOAD method with cross correlation of the different boatwhistles, individual toadfish were mapped during dawn (0523 -0823), midday (1123 -1423), dusk (1723 -2023) and night (2323 -0223) to examine the relationship between temporal and spatial trends. Seven individual males were identified within 0.5 -24.2 m of the hydrophone array and 0.0 -18.2 m of the other individuals. Uncertainty in passive acoustics localization was investigated using computer simulations as < 2.0 m within a bearing of 033 to 148˚ of the linear hydrophone array. Passive acoustic monitoring is presented as a viable tool for monitoring the positions of acoustically sensitive species, like the oyster toadfish.The method used in this study could be applied to a variety of soniferous fishes, without disturbing them or their environment. Understanding the location of fishes can be linked to temporal and environmental parameters to investigate ecological trends, as well as to vessel activity to discuss how individuals' respond to anthropogenic noise. Highlights-Passive acoustic localization pinpointed the location of toadfish, Opsanus tau -The methodology was based on time of arrival differences and cross correlation -Seven individual boatwhistles/toadfish were localized -The method described is useful to investigate ecological trends -Identifying acoustically sensitive areas can inform management decisions

Seasonal Variation of Captive Meagre Acoustic Signalling: A Manual and Automatic Recognition Approach

“…While traditional survey methods are expensive, time consuming and dependent on weather conditions and human effort, passive acoustic monitoring (PAM) coupled with automatic recognition methods is emerging as a cost-effective non-intrusive method to monitor vocal animals in the wild as well as habitat health and biodiversity at temporal and geographical scales [5][6][7][8][9][10]. Consequently, PAM can be an efficient method to detect vocal fish and identify the onset, duration, and periodicity of reproductive activities and possibly changes in fish abundance [11,12]. This information is crucial for the management of exploited species (i.e., seasonal fishery closures designed to protect spawning fish) and conservation of essential fish habitat.…”

Seasonal and Daily Patterns of the Mating Calls of the Oyster Toadfish, Opsanus tau

“…1; Audio S1, available online). Spectral consistency in the call and high site fidelity exhibited by the males (Fish, 1972;Fine, 1983;Edds-Walton et al, 2002;Putland et al, 2018) allowed individuals to be tracked with a high degree of confidence for extended periods (72 hours).…”

“…The boatwhistle of each male has a unique acoustic signature (Fish, 1972;Fine, 1983;Edds-Walton et al, 2002;Putland et al, 2018) that consists of a brief high-amplitude broadband grunt (~30-50 ms) followed by a regular pulsing period (~200-650 ms) (Tavolga, 1958;Edds-Walton et al, 2002). Each boatwhistle is characterized by differences in waveform, sound duration, and energy distribution in harmonics that allow for identification of individuals (Amorim and Vasconcelos, 2008;Putland et al, 2018). In addition, the second portion has a distinct pulse repetition rate (PRR; fundamental frequency) that ranges from 90 to 250 Hz (Winn, 1972;Edds-Walton et al, 2002;Mensinger, 2014) and is hypothesized to influence fe-male mate choice (Edds-Walton et al, 2002).…”

“…However, most previous call monitoring has been intermittent, with weekly sampling in different areas or using signal detection software to monitor large populations; thus, recording from individual oyster toadfish for extended, consecutive time periods has not been reported. It has recently been discovered that oyster toadfish have reestablished residence in Eel Pond, located next to the Marine Biological Laboratory (MBL), in Woods Hole, Massachusetts (Putland et al, 2018). Several resident toadfish were within detection range of a hydrophone deployed at the MBL dock.…”

Ecoacoustics: A Quantitative Approach to Investigate the Ecological Role of Environmental Sounds

“…When extended to an ecoacoustic approach (using appropriate metrics), PAM changes to passive ecoacoustic monitoring (PEM), which can also detect physical parameters from the environment, such as the rain regime [111], ocean weather [112], or temperature [113]. Empirical evidence of the efficiency of PEM has been accumulated on Mediterranean maqui [84], on temperate freshwater [85,114,115], and in the marine environment [116][117][118][119]. In particular, long-term monitoring of the soundscape is important to implement management and mitigation strategies [120].…”