Dear Marmam subscribers,
We are pleased to announce the
publication of the following article in the journal of Frontiers in Marine
Science, section Deep-Sea Environments and Ecology.
Romagosa, M., Cascão, I., Merchant, N.
D., Lammers, M. O., Giacomello, E., Marques, T. A. and Silva, M. A. (2017). Underwater
Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores. Frontiers in
Marine Science 4. Doi: https://doi.org/10.3389/fmars.2017.00109
Abstract: Assessment of underwater
noise is of particular interest given the increase in noise-generating human
activities and the potential negative effects on marine mammals which depend on
sound for many vital processes. The Azores archipelago is an important migratory
and feeding habitat for blue (Balaenoptera musculus), fin (Balaenoptera
physalus) and sei whales (Balaenoptera borealis) en route to summering grounds
in northern Atlantic waters. High levels of low frequency noise in this area
could displace whales or interfere with foraging behavior, impacting energy
intake during a critical stage of their annual cycle. In this study,
bottom-mounted Ecological Acoustic Recorders were deployed at three Azorean
seamounts (Condor, Açores, and Gigante) to measure temporal variations in
background noise levels and ship noise in the 18–1,000 Hz frequency band, used
by baleen whales to emit and receive sounds. Monthly average noise levels
ranged from 90.3 dB re 1 μPa (Açores seamount) to 103.1 dB re 1 μPa (Condor
seamount) and local ship noise was present up to 13% of the recording time in
Condor. At this location, average contribution of local boat noise to
background noise levels is almost 10 dB higher than wind contribution, which
might temporally affect detection ranges for baleen whale calls and difficult
communication at long ranges. Given the low time percentage with noise levels
above 120 dB re 1 μPa found here (3.3% at Condor), we would expect limited
behavioral responses to ships from baleen whales. Sound pressure levels
measured in the Azores are lower than those reported for the Mediterranean
basin and the Strait of Gibraltar. However, the currently unknown effects of
baleen whale vocalization masking and the increasing presence of boats at the
monitored sites underline the need for continuous monitoring to understand any
long-term impacts on whales.
The publication is available at:
Kind regards,
Miriam Romagosa
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Miriam Romagosa
PhD student
MARE – Marine and Environmental
Sciences Centre & IMAR Centre;
Department of Oceanography and
Fisheries, University of the Azores
9901-862
Horta
Portugal
Tel:
(351) 292200475
Fax:
(351) 292200411
E-mail:
miromagosa@yahoo.es