Caribbean Sea Soundscapes: Monitoring Humpback Whales, Biological Sounds, Geological Events, and Anthropogenic Impacts of Vessel Noise

Heather Heenehan,Caroline Reed,Wijnand De Wolf,Sofie M Van Parijs,Laurent Bouveret,Joy E Stanistreet,Fabien Védie,Omar Shamir-Reynoso,Peter J Corkeron,Angiolina Henriquez,Jeremy J Kiszka,Julien Chalifour,Genevieve E Davis,Logan Kline,Paul Hoetjes

doi:10.3389/fmars.2019.00347

Abstract

Assessing marine soundscapes provides an understanding of the biological, geological and anthropogenic composition of a habitat, including species diversity, community composition, and human impacts. For this study, nine acoustic recorders were deployed between December 2016 and June 2017 off six Caribbean islands in several Marine Parks: the Dominican Republic (DR), St. Martin (SM), Guadeloupe east and west (GE, GW), Martinique (MA), Aruba (AR), and Bonaire (BO). Humpback whale song was recorded at five sites on four islands (DR, SM, GE, GW and MA) and occurred on 49 to 93% of recording days. Song appeared first at the DR site and began 4 to 6 weeks later at GE, GW and MA. No song was heard in AR and BO, the southernmost islands. A two-week period was examined for the hourly presence of vessel noise and the number and duration of ship passages. Hourly vessel presence ranged from low (20% - DR, 30% - SM), medium (52% -MA, 54% - BO, 77% - GE) to near continuous (99% - GW; 100% - AR). Diurnal patterns were observed at BO, GE, and MA with few to no vessels present during night time hours, possibly reflecting the activity of recreational craft and fishing vessels. At the DR and GW sites, vessel traffic was ubiquitous for most of the day, likely reflecting heavy cruise ship and container ship presence. Soundscapes were diverse across islands with persistent fish choruses, sporadic sperm whale (Physeter macrocephalus) and dolphin (Delphinidae) presence at BO, minke whales (Balaenoptera acutorostrata) from late December to late February at MA and an earthquake recorded across all sites. These analyses provide an important first step in characterizing the health and species richness in Caribbean marine parks and demonstrate a surprising high anthropogenic foot print. Vessel traffic in particular contributes adversely to marine soundscapes, masking marine mammal sounds, potentially changing typical animal behavior and raising the risk of ship strike.

Highlights

Sound has low attenuation and travels effectively in sea water, moving approximately five times faster than it does in air
The Guadeloupe West (GW), Guadeloupe East (GE), and MA sites were all located within the Agoa Sanctuary, with the GW site located within the National Park of Guadeloupe
This study provides a broad scale view of the composition of marine soundscapes across seven sites located throughout the Caribbean region

Summary

Introduction

Sound has low attenuation and travels effectively in sea water, moving approximately five times faster than it does in air. Where vision fails (at night, at depths where sunlight does not penetrate, and in turbid water), sound production and hearing function as efficient communication and sensory mechanisms. Since sound is efficient in light-limited habitats, marine animals have evolved to rely heavily on their use of sound for communication, foraging, and navigation (e.g., Benoit-Bird and Au, 2009; Radford et al, 2011; Janik and Sayigh, 2013, respectively). Passive acoustic monitoring (PAM) lets us exploit this key sensory modality and overcome some of the challenges of traditional visual surveys to learn about marine animals and their environment by listening. A soundscape is considered to be all sounds present in a given place over a certain period of time (Krause and Gage, 2003; Pijanowski et al, 2011)

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Results

Conclusion