Monitoring of bioacoustic diversity (fish and cetaceans), of reproductive activity, and assessment of recreational traffic and noise emitted underwater within the Marine Protected Area
By the University of Perpignan, CEFREM (F) and in collaboration with LECOB, CNRS (F)
Objectives and results
Project summary of the activities performed in 2020 and 2021 in the Cinque Terre AMP
The sea, especially the coastline, is rich in sounds of biological origin (emitted mainly by invertebrates and fish but also by cetaceans), geophysical (waves, wind, rain, etc.) and human (boats, fishing, oil prospecting, works, etc.). Together, these sounds generate real underwater soundscapes, representing a valuable source of information on the ecosystem. Acoustic ecology, or eco-acoustics, is an emerging discipline that studies these soundscapes and makes it possible to track, at the same time, the status (diversity and activity of animal communities) and anthropic pressure (human activities producing noise) of an ecosystem. All this without impact and over extended periods (weeks, months).
The project will perform sound mapping of the MPA zones (A/B and C), study and monitor biophony (sound richness and diversity, sounds related to reproduction) and anthropophony (recreational traffic and noise), as well as the effect of mitigation measures on courtship behaviour. The monitoring and reduction of noise pollution is included in the EU Marine Strategy Framework Directive (descriptor 11).
Noise recordings in zones A/B and C are used to:
Quantify biological "viability", activities related to reproduction (courtship songs) or the feeding and attendance of emblematic species (dolphins, dusky groupers, corbs).
Quantify the attendance (boat passages), estimate their sound levels emitted, and the exposure of sensitive habitats to noise pollution.
Establish the effect of management measures (no boat passages in zone A, speed limitation) on reproduction-related behaviour and thus essential to ecosystem resilience.
Planned activities for 2022
In 2022, noise monitoring will be performed over longer periods (approx. 6 months) at Mesco (zone A/B), Montenero (zone A/B) and Manarola (zone C) following a boat traffic gradient. These three zones present different levels of traffic and recreational noise and acoustic activities related to the breeding of corbs and/or dusky groupers and the (nocturnal) feeding of dolphins.
Analyses will be performed by applying standardised methods of quantifying biophony, attendance and noise emitted by passing boats. This will allow comparisons between years, with other marine areas and with anthropogenic noise levels detected in other areas of the Mediterranean and beyond.
With this sampling it will be possible to establish the periods of courtship and reproduction activity of dusky groupers, corbs and of cetacean attendance and behaviour in the Cinque Terre MPA. It will be possible to identify peaks of activity (daily and seasonal ranges) that allow "sensitive" periods to be defined.
Attendance by recreational boats, values of boat noise levels and anthropogenic background noise will be compared between areas, periods (high and low season) and with other MPAs. This makes it possible to assess the effect of current measures (zone A vs. zone C) but also to quantify the increase in anthropogenic impact during peak tourist periods.
Time series of biological and anthropogenic sounds will be overlaid to identify potentially sensitive periods or times (high biological and anthropogenic activity) and assess whether protection measures positively affect essential species and behaviours.
Three underwater acoustic recorders mounted onto concrete blocks will be used for sound monitoring.
The recordings will be made for approx. 5/6 months, including the summer months with peaks of both biological and sound activities (reproduction of coastal species, sound richness) and human ones.