SEAFLOOR HABITAT RECOVERY MONITORING PROGRAM (SHRMP)
To
assess the impacts on sanctuary resources due to anthropogenic
activity such as decades of commercial fishing and the installation
of the Hibernia Cable it is necessary to monitor both impacted
and non-impacted areas. On May 1, 1998 the Western Gulf of Maine
Closed Area (WGoMCA) was closed by the New
England Fisheries Management Council to all commercial fishing
of groundfish (such as Atlantic cod, Gadus morhua) and has remained
closed since that date. The southwest corner of the closed area,
which overlaps the Stellwagen Bank National Marine Sanctuary (SBNMS)
for a total of 132 nm2, or 22% of the Sanctuary, presented the
opportunity to study seafloor habitat recovery following anthropogenic
disturbance by bottom-contact mobile fishing gear (such as trawls
and dredges). It is important to note that the closed area does
not exclude all fishing activities, with commercial shrimp trawling,
recreational fishing and other activities continuing to occur
within the WGoMCA. As such, the WGoMCA represents an area of "reduced
impact" to compare to actively fished areas, rather than
a true un-impacted reference area.
The
Seafloor Habitat Recovery Monitoring Project (SHRMP) was initiated
in April 1998, one week prior to the closure of the WGoMCA, to
investigate the recovery rates of seafloor habitat (physical and
biogenic) and associated taxa (such as fishes) in the SBNMS following
impacts from fishing. A total of eight stations were identified
in four major habitat types-piled boulder, gravel, sand, unconsolidated
mud-on either side of the WGoMCA boundary. Annual sampling is
conducted using remotely operated vehicles, video drift camera
systems, side scan sonar, seafloor-mounted current profilers,
and bottom grabs.
Analysis
of hard-bottom epifaunal invertebrate data from still photographs
in 2001 showed invertebrate species richness and species diversity
to be greatest at the piled boulder station inside the (WGoMCA).
Richness and diversity was higher at Boulder IN than at Boulder
OUT, and was also higher relative to both of the gravel stations.
There were no differences in either species richness or diversity
between the two gravel stations. In fact, the transects conducted
at the Gravel OUT station had absolutely greater richness than
the Gravel IN station. This may be attributable to high concentrations
of fixed gear at the Gravel OUT station which effectively exclude
mobile fishing gear from the area.
Invertebrate
organisms in unconsolidated mud and sand habitats from bottom
grab samples in 1998, 2001 and 2002 were counted and identified
to the lowest possible taxonomic level. The total number of species
counted was 234, with 22,099 organisms for all samples. Infaunal
data were analyzed at both the family and species level. Cluster
analyses of invertebrates in both unconsolidated mud and sand
habitats showed a clear separation based on substrate type. This
separation was expected because of the difference in substrate
type alone. The cluster analyses for both invertebrate families
and species levels for 2001 indicated a separation between stations
inside and outside of the WGoMCA for both mud and sand habitats.
In
September 2000, the Hibernia fiber optic cable was laid from Boston,
Massachusetts to Halifax, Nova Scotia, crossing the Sanctuary
for 19.8 km along its northern boundary. The cable was laid by
a SEAPLOW into a trench measuring approximately 3 m across, with
a targeted burial depth of 1.5 m into the seafloor. The actual
depth of burial into the seafloor was between 0.5 and 0.75 m along
the route within the Sanctuary. In August 2001, several sites
along the cable route and in adjacent areas were added to the
existing SHRMP stations to investigate the recovery of seafloor
habitats following the laying of the cable by plow. Sampling at
the 8 gear impact stations and at locations along the fiber optic
cable route is conducted annually.
The
SHRMP is a collaborative effort between the SBNMS and scientists
at the Pfleger Institute
of Environmental Research (PIER), the National
Undersea Research Center at the University of Connecticut (NURC-UCONN),
the US
Geological Survey in Woods Hole, Massachusetts, the University
of Maine, and Brown
University (Brown participated from 2001-2003). Financial
support has been provided by SHRMP for scientists, undergraduates
and graduate students (both Masters and Doctoral), post-doctoral
fellows, and research technicians at each of these institutions.
Technical support for the operation and maintenance of the equipment
associated with the project is provided by NURC-UCONN. The project's
relational database was designed by, and is supported by, Perot
Systems through a contract with SBNMS. These data include, but
are not limited to; the identification and relative abundance
of epifaunal organisms from video transects and still photographs;
and infaunal organisms from bottom grabs and box cores.
This on-going collaboration is scheduled to continue through 2007
(dependent on funding).
Contact:
James Lindholm, Ph.D.
Pfleger Institute of Environmental Research
901-B Pier View Way
Oceanside, CA 92054
Phone: 760-721-1441
Email: james@pier.org
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