current (and past) research includes these projects:
|| Acoustic scattering from hake and Humboldt
squid in the Pacific Ocean
In conjunction with collaborators
at Oregon State University and the National Marine Fisheries Service,
we are conducting a study on the acoustic scattering properties of hake
(a commercially-fished species) and Humboldt squid (a recent immigrant)
along the Pacific coast of Washington, Oregon, and California. Using
lab, dock-side, and ship-based experiments and surveys, we hope to
improve our ability to assess the distribution and abundance of these
pelagic organisms as well as determine the scattering mechanisms and
properties of these animals.
| The distribution, abundance, and scattering
characteristics of Antarctic salps.
Over two field seasons in 2010 and 2011, we will travel to Antarctica
and conduct surveys and experiments on salps (Salpa thompsoni
primarily). These gelatinous animals occur in great abundances (or
blooms) in this region and can be very important in terms of oceanic
carbon transport. In addition, they compete with Antarctic krill for
the title of dominant zooplankton which can have important effects on
the other animals in this region (whales, seals, penguins and other sea
birds) who rely on krill as their primary food source.
| The effect of zooplankton populations on the
behavior of marine mammals.
In conjunction with collaborators at Penn State and the Provincetown
Center for Coastal Studies, we are measuring the distribution and
abundance of zooplankton populations in Cape Cod Bay and Stellwagen
Bank National Marine Sanctuary. Our net tow, acoustic backscatter, and
hydrographic data will be combined with data from scientists who are
monitoring the behavior of right and humpback whales in these waters.
We are examining what role do zooplankton prey play in determining
marine mammal behavior.
We are also working with a group of researchers at Duke University,
UMass Boston, and elsewhere on studying the role that Antarctic krill
play on the behavior of Humpback whales in Antarctica. We participated
in the MISHAP X cruise in May and June 2010 and are currently analyzing
data from this project. [photo by Allison Stimpert]
|Remote assessment of zooplankton, nekton,
underwater noise and animal vocalizations.
are working with researchers at Penn State University and the
University of Washington on the analysis of data from moorings equipped
with oceanographic and both passive and active acoustics sensors that
have been deployed in the Bering Sea and in the Northwest Atlantic.
Data from these sensors allows us to estimate the primary production
and physical oceanographic environment, presence of sea ice, presence
and abundance of zooplankton and small nekton (from the active acoustic
system) and marine mammals (from the passive acoustic system). These
data are important to understand how ecosystem dynamics are changing in
the Bering Sea as the extent and duration of winter sea ice diminishes.
In the Northwest Atlantic, we are using these data to assess prey
availability in connection with the behavior of marine mammal predators.
the Target Strength of Bering Sea Euphausiids
The walleye pollock fishery
is the largest United States fishery (in terms of landings) and is
annually studied by the NMFS Alaska Fisheries Science Center MACE
program through regular cruises in the Bering Sea. To assess the stock
of pollock, the fishery scientists use a combination of acoustic
echosounder surveys and net trawls. We are working with them to develop
an improved model of the scattering characteristics of the zooplankton
of the Bering Sea, in particular the euphausiids. Aggregations of these
animals scatter sound and can be confused with the scattering from
pollock schools. We collected and measured a variety of Bering Sea
zooplankton and are developing mathematical models that describe their
acoustic scattering so that the fishery scientists can better identify
scatterers as pollock or other biological organisms.
Using a variety
of platforms (large research vessel, small boat,
and instrumented buoys), my co-PI David Demer (SWFSC, NOAA) and I are
trying to understand the
biological and physical factors that create regions of high krill
productivity in the nearshore waters off of Livingston
Antarctica. These areas serve as the main foraging grounds for resident
penguin and fur seal populations and understanding the spatial and
temporal variability of the krill distribution is important to
understand how the ecosystem functions. Additionally, I'm working with
other scientists who study krill predators in this area to understand
how the distribution of prey (krill) is related to predator foraging
range and behavior. This project is supported by
the National Science Foundation and NOAA.
Long Island South Shore Estuary System
Understanding the local
waters of Long Island in terms of the
biological and physical oceanography is important for a variety of
reasons, including shellfish and finfish stocks, anthropogenic
influences, effect of development, and management of recreational
areas. Studies have been undertaken by several
researchers investigating many different aspects of the local estuarine
environment. Our group has investigated the influence that the ocean
inlets along the south shore of Long Island have on the temperature and
salinity distributions within the bays. Both tidal and wind-driven
circulation are the primary factors controlling the levels of salinity
and temperature within the bays which are critical factors affecting
shellfish habitat, recruitment, and growth. This project is supported
by New York Sea Grant and the SCERP foundation.
Acoustic Scattering from
Submerged Aquatic Vegetation (SAV)
indicate that some types of SAV can scatter a significant amount of
acoustic energy, and at times can even register "false bottoms" on a
depth-finder. We are investigating whether acoustics can be used to map
SAV populations, what the scattering mechanisms are for different types
of SAV, whether acoustics can be used to non-invasively study the
growth and health of SAV, and the implications for SAV scattering as a
factor for "noise" in sonar systems such as mine-detection. Initial
funding for this work was provided by UNH CICEET program.
Some of my past research areas include:
Surveys of zooplankton populations in the Ligurian
Sea to assist in assessments of marine mammal distributions
Use of multifrequency acoustics to
distinguish between biological and physical sources of scattering
Surveys of zooplankton populations in
the Gulf of Maine
Study and validation of mathematical
scattering models for different types of zooplankton