Stellwagen Bank: The Northeast Fisheries Science Center in Woods Hole deployed specially designed acoustical buoys in the Gerry E. Studds Stellwagen Bank National Marine Sanctuary. The buoys will capture three months worth of ocean sounds before they resurface, allowing s

ScienceDaily (Apr. 3, 2008) — Like sentinels
at their posts, an array of buoys equipped with underwater microphones
and other sensors will be on duty in the Stellwagen Bank National
Marine Sanctuary off the coast of Massachusetts for the next 30 months,
recording sounds from whales, fish, ships and other sources around the
clock. NOAA marine mammal scientists will analyze the biological
sounds to help develop a global monitoring network for ocean noise, an
important step in effectively managing marine sanctuary resources and
protecting endangered species like the North Atlantic right whale.

“The ocean is a noisy place,” said Sofie Van Parijs, marine mammal
acoustician at NOAA’s Northeast Fisheries Science Center (NEFSC) and a
project scientist. “It’s full of natural sounds and those from human
activities, and there is substantial evidence that the level of
man-made noise is rising. Marine mammals and many fishes are highly
dependent on sound for communication, navigation, foraging and predator
avoidance. We need to understand how these animals, especially
endangered and protected species, are impacted by sounds from many
sources to be able to better manage and protect these living
resources.”

An ocean-observing system consisting of ten autonomous recording
units will be deployed for periods of three months, each in different
parts of the Sanctuary at different times of the year, to monitor low
frequency sounds. The passive-acoustic buoys, moored to the ocean floor
and fully submerged, continually record ocean sounds around the clock
before they pop to the surface on command so the data can be retrieved
and batteries refreshed.

The three-year project began in late December with funding from the
National Oceanographic Partnership Program and a team of scientists and
engineers from NOAA Fisheries, NOAA Sanctuaries, the Bioacoustic
Research Program at Cornell University and Marine Acoustics, Inc. Van
Parijs and NEFSC colleague Denise Risch, also a marine mammal
bioacoustician, will analyze the biological sounds collected during the
study, while Sanctuary scientists Leila Hatch, Michael Thompson and
Dave Wiley will focus on the anthropogenic or human-produced sounds.
Project leader Chris Clark of Cornell University and colleagues provide
scientific guidance, hardware and software, and are working with Bill
Ellison of Marine Acoustics, Inc. on modeling ocean noise propagation
within the sanctuary.

The Gerry E. Studds Stellwagen Bank National Marine Sanctuary is an
urban marine sanctuary located in close proximity to Boston and a
densely populated coastal zone. The area has commercial fishing fleets,
heavy vessel traffic, is frequented by marine mammals like endangered
Northern right whales, and forms a critical feeding ground for
endangered fin and humpback whales. It is also home to
acoustically-sensitive marine animals like commercially important
haddock and other fishes, sharks and sea turtles.

Van Parijs says the Sanctuary is a perfect place to build a case
study that can provide a benchmark to scientifically evaluate the
impacts and interactions between various human-produced sounds and
acoustically-sensitive marine animals.

The abundance of endangered whales and human activities in the
Sanctuary will help the team address many of the recommendations made
by the National Research Council’s committee on the potential impacts
of ambient noise in the ocean on marine mammals. The committee has
cited the importance of sound in the lives of marine mammals, the
potential for harm from excessive noise, and the lack of scientific
data as to the amounts of noise introduced into the oceans by human
activities and its potential impact on marine mammals.

“We need to ground-truth current sampling and analysis techniques
and identify gaps that must be addressed prior to implementing a
large-scale domestic or international monitoring program,” Van Parijs
said. “The products of this project will be a suite of tools designed
to be transferable for use in other ecological regions or sanctuaries
along with an extensive database of sounds. This project is a first
step toward a much larger goal of establishing a global passive
acoustic monitoring network to measure ambient noise levels in a
variety of locations.”

The first set of project buoys deployed in December were recently
recovered from the northeast corner of the Sanctuary and were
redeployed March 7 in the southwest corner, where endangered Northern
right whales are congregating. The area is a primary nursing and
feeding ground for the whales in the spring.

Ten similar buoys were used successfully in the Sanctuary in 2006
during a one-year pilot project in preparation for this study. This is
the first project to record all types of sounds over a long time period
in a relatively large area in an effort to characterize the marine
acoustic environment and the health of an urbanized, highly productive
ecosystem. One potential use of the information: scientists could
track whale migration patterns and ship movements to help prevent
collisions, a leading cause of whale mortality.

“Our goals are to map the low-frequency noise budget throughout the
Sanctuary, identify and quantify the contributing sources of sounds,
and determine whether or not these noises have the potential to impact
endangered marine mammals and fishes,” said David Wiley, the
Sanctuary's research coordinator. “The results from this project will
have local, national and international implications.”

Adapted from materials provided by NOAA National Marine Fisheries Service.