Smooth Bottom Net Trawl Fishing Gear Effect on - New England ...

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NOAA/NMFS Unallied Science Project, Cooperative Agreement NA16FL2264 May 2005 <strong>Smooth</strong> <strong>Bottom</strong> <strong>Net</strong> <strong>Trawl</strong> <strong>Fishing</strong> <strong>Gear</strong> <strong>Effect</strong> on the Seabed: Investigation of Temporal and Cumulative <strong>Effect</strong>s BKAM/CR 1.4 Survey <strong>Gear</strong> Selection The majority of survey and sampling equipment selected for the study is owned by CR Environmental and included: • Dual frequency EdgeTech Model 272 TD side-scan sonar system consisting of an analog towfish with an ACI board, topside computer with digital interface, power supply, and Chesapeake Technology SonarWiz software and SonarWeb acquisition and processing software; • SyQwest Bathy500 precision echosounder with a 3 degree narrow beam transducer • Lightweight custom aluminum towed video sled with miniature Deep Sea Power & Light color video camera, video lights and navigation interface; • Ted Young benthic grab sampler with a stainless steel frame, camera and light brackets, and stability fin; • Seabird Seacat CTD system with a Seapoint OBS sensor ; • Trimble AG132 DGPS systems with HYPACK survey software; SAIC provided the Benthos Model 3731 Sediment-Profile Camera System to obtain the sediment profile images. Additional oceanographic support equipment provided by BKAM and CR Environmental was fabricated by former Scituate, MA, fishermen, Bob Stevermen, and included an oceanographic winch, hydraulic A-frame, and side-mounted transducer boom. 1.5 Experimental Design The cumulative impact of trawling with smooth bottom net trawl gear on soft bottom sea-floor characteristics and benthic communities was examined in two areas, “Mud Hole” and “Little Tow”, historically subjected to differing fishing pressure (Figure 1.0-1). Mud Hole is more intensively fished with mobile gear, and Little Tow has less mobile gear pressure due to its shape and size, and a high density of fixed gear (lobster traps and gill nets). For a more complete description of these study areas see our 2001 study at www.crenvironmental.NOAAtrawl.html. Four non-overlapping, lanes or belt transects (1000 m x 100 m) were selected during our 2001 trawl study within each site: 2 experimentally trawled lanes and 2 temporal control (reference) lanes that were not experimentally trawled (Mud Hole - Figure 1.0-3, Little Tow - Figure 1.0-4). Survey and sampling operations were conducted at stations on each of the experimental and control lanes prior to the 2002 chronic experimental trawling to establish a baseline, and then once midway through the trawling (late September) and once at the end of the chronic trawling (November). 5
NOAA/NMFS Unallied Science Project, Cooperative Agreement NA16FL2264 May 2005 <strong>Smooth</strong> <strong>Bottom</strong> <strong>Net</strong> <strong>Trawl</strong> <strong>Fishing</strong> <strong>Gear</strong> <strong>Effect</strong> on the Seabed: Investigation of Temporal and Cumulative <strong>Effect</strong>s BKAM/CR Baseline sampling at the study sites (Mud Hole and Little Tow) was conducted for all lanes prior to chronic trawling in July 2002 and during the two post-chronic trawling cruises in September/October and November 2002. Data collected included: • 500 kHz side-scan sonar along the experimental trawl and control lanes; • Video footage along transects approximately one hundred meter long and run perpendicular to the experimental and control lanes at 12 stations to obtain detailed video coverage for viewing biota and physical trawl impacts; • Three replicate benthic grab samples at 8 selected stations per cruise for infaunal characterization for a total of 72 samples over the study; and one grab for sediment grain size analysis at the same 8 stations per cruise for a total of 24 samples over the course of the study; • CTD casts at each of the 12 sampling stations per cruise; • Three replicate SPI camera drops at 12 stations for a total of 108 images; • Experimental fishing trawls and the collection of flatfish stomachs was performed along the trawled lanes on each of the three cruises. Table 1.5-1 Sampling Design SITE MUD HOLE LITTLE TOW Transects Experimental Control Experimental Control PRE CHRONIC TRAWLING July 2002 Lane 1 Lane 3 Lane 2 Lane 4 Lane 1 Lane 3 Lane 2 Lane 4 500 kHz side-scan 1 1 1 1 1 1 1 1 Video sled crosstie 1 2 1 2 1 2 1 2 Benthic infaunal samples (3 replicates) 1 1 1 1 1 1 1 1 Grain size samples 1 1 1 1 1 1 1 1 CTD 3 3 3 3 3 3 3 3 SPI 3 3 3 3 3 3 3 3 Experimental <strong>Trawl</strong>s and Flatfish stomachs 1 1 1 1 POST CHRONIC TRAWLING Sept/Oct 2002 Lane 1 Lane 3 Lane 2 Lane 4 Lane 1 Lane 3 Lane 2 Lane 4 Prior <strong>Trawl</strong>s 13 13 13 13 500 kHz side-scan 1 1 1 1 1 1 1 1 Precision Bathymetry 1 1 1 1 1 1 1 1 Video sled - CT 1 2 1 2 1 2 1 2 Benthic infaunal 1 1 1 1 1 1 1 1 samples (3 replicates) Grain size samples 1 1 1 1 1 1 1 1 CTD 3 3 3 3 3 3 3 3 SPI 3 3 3 3 3 3 3 3 Experimental <strong>Trawl</strong>s and Flatfish Stomachs 1 1 1 1 6
Page 1: SMOOTH BOTTOM NET TRAWL FISHING GEA
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NOAA/NMFS Unallied Science Project,
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effective if the process of immigra
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effort, the critical pulse disturba
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Maciolek, N.J., R.J. Diaz, D. Dahle
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Table 3.3-2. Organisms observed per
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Table 3.3-4. Organisms observed per
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Table 3.3-5. Comparison of 2001 ROV
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Station LT02-1B - P2 Trawl<
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Station LT02-3A Trawl</stro
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Station LT02-4A - P1 Control Lane O
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Trawl Station Resu
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Trawl Station Resu
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Trawl Station Resu
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Table 3.6-2 2002 Trawl</str
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Table 3.6-3 (continued) CRUSTACEA A
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Table 3.6-5 Summary of Blackback (W
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Table 3.6-5 (continued) OTHERS Sarc
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Table 3.6-7 Dominant Species in Sed
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FIGURES
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Figure 1.0-2. Smooth</stron
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Figure 1.0-4 Side-scan sonar base m
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Figure 3.2.1-2 Bathymetric surface
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Number/minute 4 3 2 1 0 July Octobe
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Number/minute Number/minute 4 3 4 2
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Number/minute Number/minute 30 20 1
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Number/minute Number/minute 2.5 2 1
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Number/minute Number/minute July -
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Figure 3.4-2 For key species, the a
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Figure 3.4-4 For key species, the a
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Figure 3.4-6: Cluster analysis of M
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Figure 3.4-9 Little Tow 2002 Cluste
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Figure 3.4-12a. Little Tow 2001 and
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Note: [LT02 = Little Tow 2002 sampl
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Results of 2002 REMOTS Surveys to E
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Kg/Tow 200 180 160 140 120 100 80 6
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Kg/1000m2 Kg/1000m2 7 6 5 4 3 2 1 0
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Kg per 1000m2 350 300 250 200 150 1
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Numbe of individuals Number of Indi
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Number of individuals Number of ind
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PHOTOGRAPHS
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Photograph 2.2-2 Christopher Dunbar
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a. Chris Dunbar sieving benthic sam
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Photograph 2.7-1 CR Environmental e
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a. Fisherman Andrew Mirarchi viewin
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2001 2002 Cobble Bottom</st
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MH-3A July 2002 Pre-Trawl</
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MH-4A July 2002- Pre-Trawl<
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LT-1B July 2002- Pre-Trawl<
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LT-3A July 2002- Pre-Trawl<
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LT-4A July 2002- Pre-Trawl<
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Cobble bottom at Little Tow Small r
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2001 2002 Flounder Rock Crabs Sea S
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