CRD 01-17
Session
X: Technology/Gear
| Use
of a large-mesh panel to reduce the flatfish bycatch in the small-mesh
bottom trawls used in the New England silver hake fishery |
Session
X: Technology/Gear
Abstract No. X-1
ORAL PRESENTATION |
Presentation
Henry O. Milliken, III
NOAA/NMFS/NEFSC,
166 Water St., Woods Hole, MA 02543-1026
Bottom trawls that utilize
small mesh to capture smaller fish are subject to bycatch limits when
they are used in areas where larger regulated species reside. Bycatch
of regulated flatfish in the small-mesh bottom trawl fishery for silver
hake (Merluccius bilinearis, Gadidae) in the Northwest Atlantic
is a concern of management because the silver hake are captured in
areas that juvenile flatfish frequent. An evaluation of flatfish and
silver hake behaviors using low light underwater cameras suggested
that the two species could be separated within the mouth of a bottom
trawl. Using alternating tows, four different large-mesh panels positioned
in the lower belly of the trawl were separately evaluated, and one
proved effective at reducing flatfish bycatch while not reducing the
catch of silver hake. A large-mesh panel constructed of 1.6 mm diameter,
orange colored nylon twine in the lower belly resulted in a 73% reduction
in flatfish catch, while not affecting the catch of silver hake.
| An
efficiency comparison of a standard 8-ft NEFSC sea scallop dredge
and one rigged with rock excluding chains |
Session
X: Technology/Gear
Abstract No. X-2
ORAL PRESENTATION |
Presentation
Victor A. Nordahl, Jr.
NOAA/NMFS/NEFSC, 166 Water St., Woods Hole, MA 02543-1026
Commercial fishermen dredging
in the Northwest Atlantic for the sea scallop, Placopecten magellanicus,
regularly rig their 15-ft scallop dredges with rock excluding chains. Some
commercial scallopers believe that rock chains prevent gear damage,
reduce repair time, and limit damage to the catch caused by large rocks
found in hard bottom habitats. Hard bottom is generally considered
to be habitat with medium to large cobbles and boulders mixed with
sand and gravel. The number of vertical chains (up and downs) and
the number sweep chains (ticklers) a scalloper decides to rig over
the mouth of the dredge varies between scalloper, and habitat type. Another
belief held by many scallopers is that scallop dredge catch efficiency
is increased by adding a number of chains when fishing on hard bottom. The
Northeast Fisheries Science Center has conducted a standard sea scallop
survey since 1975 deploying an 8-ft dredge without rock excluding chains. Lately,
some questions have been raised by the Invertebrate Sub-Committee regarding
dredge efficiency on hard bottom habitats. The committee’s opinion
is that a bias exists in standard dredge tows that capture large rocks
or large amounts of substrate. A large rock or boulder may change
the performance of a dredge and reduce the efficiency during a standard
dredge tow. In response to this, a two part paired dredge tow experiment
was conducted in the spring and summer of 2001 to address the issue
of dredge efficiency differences on two different bottom types. The
study was designed to compare numbers and size frequencies of scallops,
finfish bycatch, and substrate retention and exclusion between a standard
scallop dredge and one rigged with rock chains. Twenty-one pairs of
dredge tows were occupied on hard bottom on the western side of the
Great South Channel and twenty-eight pairs of dredge tows were occupied
on soft bottom in and around the Nantucket Lightship Closed area. Analysis
of covariance will be used to test for the differences in catch and
calculate a calibration factor for the dredge fitted with the set of
rock chains. Paired t-test and contingency tables will be used
to test for differences in by-catch and substrate. A Kolmogorov-Smirnov
test will be used to detect differences length frequency distribution. Based
on this study, the NEFSC will decide whether to implement the use of
rock chains during the standard scallop survey. Results were not available
from the study at this time, but will be presented at the NMFS 2001
Science Symposium.
| Fisheries
acoustics at the NEFSC |
Session
X: Technology/Gear
Abstract No. X-3
ORAL PRESENTATION |
Presentation
Peter Chase, William L. Michaels,
J. Michael Jech, William J. Overholtz, Wendy L. Gabriel, and Elizabeth
Pratt
NOAA/NMFS/NEFSC, 166 Water St., Woods Hole, MA 02543-1026
Underwater acoustic technology
is being implemented by the NEFSC as an alternative approach to commercial
landings and bottom-trawl surveys for obtaining abundance and biomass
indices of pelagic fish species in the Gulf of Maine and Georges Bank
regions. Since 1995, acoustic cruises have been conducted using a
multiple-frequency Simrad EK500 scientific echosounder (12 kHz single
beam, and 38 and 120 kHz split beams), midwater trawls, and underwater
video. Beginning in 1998, acoustic surveys using standardized survey
designs have been conducted to estimate spawning stock biomass of Atlantic
herring (Clupea harengus). Midwater trawl gear is used to verify
species composition and underwater video is used to record fish behavior. Integration
of acoustic data with oceanographic and biological databases at the
NEFSC significantly enhances the utility of fisheries acoustic methods
for pelagic fish assessment. Research topics of the fisheries acoustics
group include comparisons of survey designs and statistical approaches
(e.g., classical and geostatistical), in situ and laboratory measurements
of acoustic backscatter by individuals, and theoretical modeling and
visualization of acoustic backscatter by individuals and aggregations
of fish.
|
Introducing
the Fisheries Scientific Computer
System (FSCS) |
Session
X: Technology/Gear
Abstract No. X-4
ORAL PRESENTATION |
Presentation
Nancy McHugh1,
David Benigni2, Thomas N. Stepka2, and Dennis
P. Shields2
1NOAA/NMFS/NEFSC,
166 Water St., Woods Hole, MA 02543-1026
2NOAA/NOS/Office
of Marine and Aviation Operations, 1315 East‑West Hwy., Silver Spring,
MD 20910-3282
A sophisticated data acquisition
system has been designed by the Office of Aviation and Marine Operations
(OMAO) and the Northeast Fisheries Science Center (NEFSC) specifically
to digitally collect all critical fishery-independent data aboard fisheries
research vessels. The Fisheries Scientific Computer System (FSCS)
is responsible for collecting such data as species, catch weights,
individual fish lengths and weights, gender and maturity, as well as
stomach content data. Station and oceanographic data are also collected
and integrated into the system. Once data are collected for a given
station, they are subsequently passed on to an ORACLE database ingestion
application, which enables data to be audited before it is examined
on shore.
FSCS now replaces manual
data recording which shaves months off the time required to make cruise
data available to researchers. The system performs all sub-sampling
calculations and runs real time audit checks to find data entry errors. Data
can be sent back to shore electronically to provide researchers with
up to date catch information and to check for any inconsistencies. The
hardware suite consists of two redundant network servers and each of
the following at three sampling locations: PC with touch-screen terminal,
electronic fish measuring board, electronic weight scale, bar code
scanner and label printer. FSCS went fully operational during the
2001 NEFSC spring bottom trawl survey and is currently being implemented
on the NOAA ships Albatross IV and Delaware II during bottom trawl,
scallop and hydroacoustic surveys.
Keywords:
data entry at sea, fisheries data acquisition
| Results
for recent NIST intercomparison exercises from the organic group
of the J. J. Howard Marine Science Laboratory |
Session
X: Technology/Gear
Abstract No. X-5
ORAL PRESENTATION |
Bruce W. Dockum
NOAA/NMFS/NEFSC, 74 Magruder Rd., Highlands, NJ 07732
The organic laboratory at
the James J. Howard Marine Science Laboratory at Sandy Hook has participated
in the National Institute of Standards and Technology (NIST) Intercomparison
Exercise Program for Organics in the Marine Environment for many years. In
this yearly program, NIST conducts a yearly interlaboratory comparison
exercise to provide a mechanism for participating laboratories, from
the federal, state/municipal, university/college, private, and international
sectors, to evaluate the quality and comparability of their analytical
methodology in the measurement of selected organic contaminants in
marine samples. The organic contaminants include selected polyaromatic
hydrocarbons (PAH), chlorinated pesticides, and polychlorinated biphenyls
(PCB) which are extracted from mussel or fish homogenates or wetted
marine sediment. The analyte results determined by the organic
group at the Howard Laboratory for recent exercises will be presented.
| Remote
sensing and GIS applications for studies on protected species |
Session
X: Technology/Gear
Abstract No. X-6
ORAL PRESENTATION |
Presentation
Chris Orphanides and Grayson
Wood
NOAA/NMFSNEFSC,
28 Tarzwell Dr., Narragansett, RI 02882-1152
The use of satellites and
remote sensing technology for synoptic observation of large areas of
the marine environment has been well developed over the past 20 years. For
most part, scientific use of these satellite data has been largely
limited to studies of physical oceanographic processes. Recent adaptations
of geographical information systems (GIS) for use in the marine environment
have shown that they are an important medium by which physical and
biological information can be co-analyzed. This notion is well represented
by the applications of sea-surface height measurements and other satellite-derived
information to a number of investigations in the Central Pacific, specifically
(a) the dispersion and transport of lobster larvae and (b) the behavior
patterns of sea turtles.
The present project, underway
at the Narragansett Lab, makes use of GIS tools to analyze the data
from a number of sea-viewing satellite sensors and from fisheries observer
logs, in order to focus on sea turtle by-catch within the Atlantic
longline industry. Information collected in this manner will be combined
with actual tracking data gathered by NEFSC tagging operations in 2002. Preliminary
analyses suggest that sea turtle habitat in the marine environment
is closely linked with ocean fronts, and that sea turtles may often
congregate along the edges of warm core rings and zones of convergence. These
and other habitat preferences are being investigated on various spatial
and temporal scales through assessing the correlation between sea turtle
location and satellite derived measurements of sea-surface temperature,
locations of persistent fronts, chlorophyll concentrations, upwelling
/ downwelling, and other habitat parameters.
Keywords:
protected species, remote sensing, satellite imagery, GIS, sea turtles
