Temporal and spectral patterns of fish choruses in two protected areas in southern Atlantic

- A first detailed analysis of fish choruses recorded in Sao Paulo State, Brazil.
- Five chorus types showed well-defined daily periodicities, mainly at dawn and dusk.
- Temporal and spectral characteristics of the studied choruses are described.
- The methodology was based on SPL, spectrograms, PSD and cepstral analyses.
- The reported characteristics are useful to catalog fish sounds in the studied region.

The Laje de Santos Marine State Park (LSMSP) and Xixová-Japuí State Park (XJSP) are two protected areas (PAs) located in the southern Atlantic Brazilian coast. One month of continuous underwater sound recordings allowed determining that durable fish choruses was a major contributor of LSMSP and XJSP soundscapes. The choruses showed well defined daily periodicities and exceeded background ambient noise for some hours every day, principally at dawn and dusk. This work describes the daily temporal patterns and spectral characteristics of the studied PAs choruses. Annotations of some chorus temporal descriptors (start, peak and end time instants) allow obtaining a precise statistical representation of diel chorus occurrence. Average Power Spectral Density and cepstral analysis were used to determine quantitative values for choruses spectral characterization. Results show that the passive acoustic technique could be a cost-effective method for management and fish monitoring in PAs.