Thread by @SBBioacustica

FISH CHORUS AND VESSEL NOISE IN A MARINE PROTECTED COASTAL REEF
Alfredo Borie-Mojica
Universidade Federal de Alagoas, UE Penedo

Fish sounds can be emitted in different contexts for social communication, and serve as natural markers of fish species.

The passive acoustic method allows researchers to identify and monitor fish populations just by listening to them. Also, anthropogenic noise, including vessel traffic could interferes in fish communication.

The study was developed in a coastal reef in Tamandaré beach, “Costa dos Corais” Marine Protected Area (CCMPA). Underwater recordings were made using a hydrophone that allowed continuous recordings of 24 h day-1 for 3 months (December 10, 2016, to March 10, 2017).

The temporal characterization of each chorus signal detected included parameters like initial and final time (hh:mm); total chorus duration; low- and high-frequency limits (Hz); and dominant frequency (Hz).

The study detected a total of six fish choruses in the marine protected zone of Tamandaré. These choruses had typical characteristics, being produced by trains of pulses and frequencies up to 3000 Hz.

The soundscape in the same area were composed by fish chorus and acoustic characterization were similar to those found in this study. The fish choruses of the present study presented similar characteristics to those of coastal marine protected areas in southeastern Brazil.

This study detected and assessed the occurrence of 289 anthropogenic acoustic signals originating from fishing vessels (n = 196), recreational motorboats (n = 72), and ships (n = 21). The vessels had usually low dominant frequencies, with higher peaks below 120 Hz.

The results showed a complex temporal variation of the choruses, implying the need of greater effort to monitor fish population. Fish choruses and the anthrophonic noises of different vessels can be monitored using the passive acoustic method.