NEAR TERM OBSERVATIONS OF THE EFFECTS OF SMOOTH BOTTOM NET TRAWL FISHING GEAR ON THE SEABED


F/V Christopher Andrew	F/V Andrea J. II

F/V Lady Irene	F/V Yankee Rose

Prepared for:

U.S. Department of Commerce NOAA/NMFS
Northeast Regional Office
Northeast Cooperative Research Initiative
One Blackburn Drive
Gloucester, MA 01930-2298

Submitted by:

Boat Kathleen A. Mirarchi, Inc.
67 Creelman Drive, Scituate, MA 02066
&
CR Environmental, Inc.
639 Boxberry Hill Road, East Falmouth, MA 02536

October 2003

NMFS Cooperative Research Partners Program Northeast Region

1.0 INTRODUCTION

2.0 RECONNAISSANCE SURVEY AND SELECTION

OF THE STUDY LANES

3.0 TRAWL IMPACT STUDY FIELD OPERATIONS

AND METHODS

3.1 Navigation Methods

3.2 Water Column Sampling Methods

3.3 Side-scan Methods

3.4 Benthic Sampling Methods

3.5 ROV, Video Sled and Dredge Survey Methods

3.6 Experimental Trawling Methods

4.0 TRAWL STUDY RESULTS

4.1 Water Column Characteristics

4.2 Geophysical Results

4.3 Remotely Operated Vehicle Video,

Towed Video Sled, and Dredge Results

4.4 Benthic Results

4.5 Fisheries Survey Results

5.0 SUMMARY

6.0 REFERENCES

PHOTOGRAPHS

Photograph 1.4-1 F/V Christopher Andrew

Photograph 1.4-2 F/V Yankee Rose

Photograph 1.4-3 F/V Lady Irene

Photograph 1.4-4 F/V Andrea J. II

Photograph 3.3-1 Scientist Chip Ryther with Edgetech Side-Scan Towfish

Photograph 3.4-1 Fisherman Scott McKinnon and John Welch Sieving Benthic Samples on the Lady Irene

Photograph 3.4-2 Fishermen Sorting Benthic Samples

Photograph 3.5-1 Scientist Chip Ryther Deploying Video Sled

Photograph 3.5-2 Fisherman Frank Mirarchi Recovering Mini-Rover ROV

Photograph 3.5-3 Scientist Barbara Hecker with Experimental Dredge

Photograph 4.3-1 Striations in Muddy Sand Bottom from Cookies (3 to 6 inch Diameter Rubber Discs) Strung on the Trawl Sweep and Ground Cables

PLATES

Plate 4.3-1 Selected Images of Bottom Substrate at the Mud Hole and Little Tow

Plate 4.3-2 ROV and Video Sled Screen Captures of Representative Fish Species Observed at the Mud Hole and Little Tow Sites

Plate 4.3-3 High Resolution ROV Still Photos of Representative Fish Species Observed at the Mud Hole and Little Tow

Plate 4.3-4 ROV and Video Sled Screen Captures of Select Invertebrates

Plate 4.3-5 High Resolution Still Photos of Select Invertebrates at Mud Hole and Little Tow

Plate 4.3-6 Trawl Impacts Showing Door Furrows and Bottom Smoothing at Mud Hole and Little Tow

Plate 4.3-7 Video Screen Captures of American Lobster (Homarus americanus) and Rock Crab (Cancer irroratus) in Door Furrows at Mud Hole Lane 3 Following Trawling

TABLES

Table 4.3-1 Video Sled Raw Counts

Table 4.3-2 ROV Raw Counts

Table 4.3-3 Organisms Observed Per Minute in the Towed Video Sled Survey of Mud Hole

Table 4.3-5 Organisms Observed Per Minute in the Towed Video Sled Survey of Little Tow

Table 4.3-6 Organisms Observed Per Minute in the ROV Survey

Table 4.3-7 Organisms Observed Per Minute in the ROV Survey of Mud Hole

Table 4.3-8 Organisms Observed Per Minute in the ROV Survey of Little Tow

Table 4.3-9 Dominant Taxa (Expressed as the Number of Organisms Observed per Minute) Responsible for the Clustering Structure of Video Sled Data

Table 4.4-1 Numerically Dominant Species – Mud Hole and Little Tow Sites, Massachusetts Bay, July 2001

Table 4.4-2 Benthic Infauna Descriptive Metrics for Mud Hole & Little Tow Stations Pre- and Post- Trawling July 2001

Table 4.4-3 Correlations Between Benthic Ecological Metrics and Sediment Properties

Table 4.5-1 Finfish, Sharks, and Common Macro-Invertebrates in Little Tow and Mud Hole Trawl Catches, July 2001

Table 4.5-2 Species Composition of Bottom Trawl Catches (kg) for Six Individual Tows in Trawl Lanes 1 and 3 at Little Tow, for All Six Tows in Each Lane, and for All 12 Tows in Both Lanes, July 15, 2001

Table 4.5-3 Species Composition of Bottom Trawl Catches (Percent by Weight) for Six Individual Tows in Trawl Lanes 1 and 3 at Little Tow, for all Six Tows in Each Lane, and for All 12 Tows in Both Lanes, July 15, 2001

Table 4.5-4 Species Composition of Bottom Trawl Catches (kg) for Six Individual Tows in Lanes 1 and 3 at Mud Hole, for All Six Tows in Each Lane, and for all 12 tows in Both Lanes, July 17, 2001

Table 4.5-5 Species Composition of Bottom Trawl Catches (percent by weight) for Six Individual Tows in Trawl Lanes 1 and 3 at the Mud Hole, for all Six Tows in Each Lane, and for All 12 Tows in Both Lanes, July 17, 2001

Table 4.5-6 Volume of Flounder Stomach Contents (ml)

Table 4.5-7a Mud Hole Ranked Prey Abundance in Fish Stomach Samples – July 2001

Table 4.5-7b Little Tow Ranked Prey Abundance in Fish Stomach Samples- July 2001

Table 4.5-8 Stomach Cluster Analysis – Dominant Prey Species Responsible for Clustering Structure

Table 4.5-9 Stomach Cluster Analysis – Ten Dominant Prey Species

FIGURES

Figure 1.2-1                Locus Map of the Mud Hole Little Tow Study Site off Scituate, MA
Figure 1.2-2                Smooth Bottom Net Trawl
Figure 1.6-1                Side-Scan Sonar Base Map of Heavily Fished Mud Hole

Figure 1.6-2 Side-Scan Sonar Base Map of Lightly Fished Little Tow

Figure 2-1 Bathymetric Contour Maps of the Mud Hole and Little Tow

Figure 3.3-1 Example of Image Manipulation Technique Used to Facilitate Substrate Delineations

Figure 4.1-1 NOAA Wave Heights

Figure 4.1-2 Contours of Near-Bottom Wave Current Speed Driven by Northeasterly Wind of 14 m/s (28 knots) (from USGS Fact Sheet 172-97. February 1998)

Figure 4.2-1 Bottom Habitat Index Map of Mud Hole

Figure 4.2-1a Ridges of Hard Material at Mud Hole

Figure 4.2-1b Sand Waves at Mud Hole

Figure 4.2-1c Muddy Sand at Mud Hole

Figure 4.2-1d Flat Hard Sand and Armor at Mud Hole
Figure 4.2-1e Sandy Mud at Mud Hole

Figure 4.2-2 Bottom Habitat Index Map of Little Tow

Figure 4.2-2a Ridges of Hard Material at Little Tow

Figure 4.2-2b Sand Waves at Little Tow

Figure 4.2-2c Muddy Sand at Little Tow

Figure 4.2-2d Flat Hard Sand and Shell Armor at Little Tow

Figure 4.2-2e Undefined Hard Bottom at Little Tow

Figure 4.2-3 Bottom Habitat Map of Mud Hole

Figure 4.2-4 Bottom Habitat Map of Little Tow

Figure 4.2-5a Map of Digitized Gear Marks – Mud Hole Pre-Trawl

Figure 4.2-5b Map of Digitized Gear Marks – Mud Hole Post-Trawl

Figure 4.2-5c Map of Digitized Gear Marks – Little Tow Pre-Trawl

Figure 4.2-5d Map of Digitized Gear Marks – Little Tow Post-Trawl

Figure 4.2-6a Side-Scan Sonar Record of Gear Disturbance to Sand -

Little Tow

Figure 4.2-6b Side-Scan Sonar Record of Gear Disturbance to Mud – Mud Hole

Figure 4.2-7a&b Density and Orientation of Trawl Marks at Mud Hole Lane 1 Pre- and Post-Trawl

Figure 4.2-8 Pre-Trawl (Top) and Post-Trawl (Bottom) Sediment Composition for Mud Hole Sample Stations

Figure 4.2-9 Pre-Trawl (Top) and Post-Trawl (Bottom) Sediment Composition for Little Tow Samples Stations (Percent of Total)

Figure 4.3-1 Time-Normalized Video Sled Observations of Fish and Invertebrates at Little Tow and Mud Hole

Figure 4.3-2 Mud Hole Video Sled Biological Observations – Lanes 1 & 2 Pre-Trawl

Figure 4.3-3 Mud Hole Video Sled Biological Observations – Lanes 3 & 4 Pre-Trawl

Figure 4.3-4 Little Tow Video Sled Biological Observations – Lanes 1 & 2 Pre-Trawl

Figure 4.3-5 Little Tow Video Sled Biological Observations – Lanes 3 & 4 Pre-Trawl

Figure 4.3-6 Mud Hole ROV Biological Observations – Relative Abundance of Select Species in Towed Lane 1 and Control Lane 2 – Before and After Experimental Trawling

Figure 4.3-7 Mud Hole ROV Biological Observations – Abundance of Select Species in Trawled Lane 3 and Control Lane 4 – Before and After Experimental Trawling

Figure 4.3-8 Little Tow ROV Biological Observations – Relative Abundance of Selected Species in Trawled Lane 1 and Control Lane 2 – Before and After Experimental Trawling

Figure 4.3-9 Little Tow ROV Biological Observations – Relative Abundance of Selected Species in Trawled Lane 3 and Control Lane 4 – Before and After Experimental Trawling

Figure 4.3-10 Video Sled Similarity Analysis

Figure 4.4-1 Similarity Analysis for Species Found in All Benthic Grab Samples (i.e., Pre- and Post-trawl, Control and Experimental Lanes) from Little Tow and Mud Hole, Massachusetts

Figure 4.4-2 Species Richness – Gloucester

Figure 4.4-3 Faunal Density – Gloucester

Figure 4.5-1 Length Frequency Distribution for Yellowtail Flounder at Little Tow

Figure 4.5-2 Length Frequency Distribution for Winter Flounder at Little Tow

Figure 4.5-3 Length Frequency Distribution for Spiny Dogfish at Little Tow

Figure 4.5-4 Catch Rates (kg/tow) of Yellowtail and Winter Flounder, other Demersal Finfish, and Crabs in Consecutive Bottom Trawl Tows in Trawl Lanes 1 and 3 at Little Tow, July 15, 2001.

Figure 4.5-5 Total Catch Rates (kg/tow) for all Species Caught in Consecutive Bottom Trawl Tows at Little Tow, July 15, 2001

Figure 4.5-6 Densities (number per 1000 square meters) of Principal Demersal Species in Trawl Lane 1 at Little Tow, July 15, 2001

Figure 4.5-7 Densities (number per 1000 square meters) of Principal Demersal Species in Trawl Lane 3 at Little Tow, July 15, 2001

Figure 4.5-8 Length Frequency Distribution for Yellowtail Flounder at Mud Hole

Figure 4.5-9 Length Frequency Distribution for Winter Flounder at Mud Hole

Figure 4.5-10 Length Frequency Distribution for Spiny Dogfish at Mud Hole

Figure 4.5-11 Catch Rate (kg/tow) of Yellowtail Flounder, other Demersal Finfish, and Crabs in Consecutive Bottom Trawl Tows in Trawl Lanes 1 and 3 at the Mud Hole, July 17, 2001

Figure 4.5-12 Total Catch Rates for all Species Caught in Consecutive Bottom Trawl Tows at the Mud Hole, July 17, 2001

Figure 4.5-13 Densities (number per 1000 square meters of Principal Demersal Species in Trawl Lane 1 and 3 at the Mud Hole, July 15, 2001

Figure 4.5-14 Mud Hole – Average Stomach Volume of Winter Flounder and Yellowtail Flounder from Trawled Lanes 1 and 3, July, 2001

Figure 4.5-15 Little Tow – Average Stomach Volume of Winter Flounder and Yellowtail Flounder from Trawled Lanes 1 and 3, July 2001

Figure 4.5-16 Little Tow Winter Flounder Lane 1 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-17 Little Tow Winter Flounder Lane 3 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-18 Mud Hole Winter Flounder Lane 1 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-19 Mud Hole Winter Flounder Lane 3 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-20 Little Tow Yellowtail Flounder Lane 1 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-21 Little Tow Yellowtail Flounder Lane 3 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-22 Mud Hole Yellowtail Flounder Lane 1 – Prey Selection as a Percent of Stomach Volume, July 2001

Figure 4.5-23 Mud Hole Yellowtail Flounder Lane 3 – Prey Selection as Percent of Stomach Volume, July 2001

Figure 4.5-24 Cluster Analysis of Ranked Prey Abundances

APPENDICES

Appendix A Equipment Specifications

Appendix B Field Log July 2001

Appendix C Benthic Invertebrate Guide for Sorting

Appendix D Water Quality Profiles

Appendix E Sediment Grain Size

Appendix F Dredge Data

Appendix G Benthic Data and Grab Coordinates

1.0 INTRODUCTION

1.1 Background

The 1996 Magnuson-Stevens Fishery Conservation and Management Act mandates that regional fishery management councils must designate essential fish habitat (EFH) for each managed species, assess the effects of fishing on EFH, and develop conservation measures for EFH where needed (Auster and Langton, 1999). This laudable objective is a reflection of recent worldwide concern of the effects of fishing on fish habitat, concerns by fishermen upon commercial fish production and concerns by environmentally motivated individuals and groups of effects upon the abundance and diversity of benthic ecosystems for their own sake.

One of the most recent and extensive literature reviews on the subject of fishing gear impacts is that of Auster and Langton presented at American Fisheries Society Symposium 22 in 1999. The review includes 154 references, over half of which were published in the past decade. The authors divided fishing effects into three components: (1) impacts on structural components of the environment, (2) impacts on benthic community structure (abundance, diversity), and (3) impacts on ecosystem-level processes (productivity). All studies reported immediate impacts on resident fauna and a decrease in habitat heterogeneity.

With respect to the first category, a review of 22 studies all showed measurable impacts of mobile gear (i.e. trawls) on structural components of habitat, namely decreased habitat complexity. One series of studies showed tight coupling between loss of emergent epifauna and fish productivity, and a shift in fish species composition to less commercially desirable species along the northwest continental shelf of Australia (Sainsbury 1987, 1988, 1991 and Sanisbury et al. 1997).

With respect to the second category, effects on benthic community structure, these were found to be highly variable and long-term effects were “not easily characterized.” The longest time series studies of fishing gear impacts were conducted in the heavily fished Wadden Sea, and showed “no long-term trends in abundance of 42 common benthic species over 100 years” but found 11 of these species showed considerable variability (Reise, 1982; Riesen and Reise, 1982). Factors that confound many of the studies are the absence of truly undisturbed reference areas and natural disturbance and variability in benthic ecosystems. However, some patterns have emerged from these studies. Impacts of fishing gear are least severe and most short lived in communities that undergo periodic disturbance and are dominated by short-lived species. In contrast, fishing gear impacts are thought to be most severe and long lived in relatively stable environments dominated by long-lived species.

Less conclusive evidence is available concerning fishing effects on ecosystem level processes (productivity), leading Auster and Langton to conclude that the “effects of disturbances caused by fishing to benthic primary production are difficult to predict.”

It is clear that for regional fisheries management councils to “assess the effects of fishing on EFH,” more controlled studies need to be conducted, specifically time studies before and after normal fishing activities and specifically for identifiable types of EFH’s.

To date, much of the research on otter trawling induced habitat impacts in the Gulf of Maine has focused on long-term cumulative changes to sand, gravel, or biogenic bottom communities in areas open or closed to fishing activity. Much less is known about the impacts of fishing gear on soft bottom habitats. A recent analysis of quantitative information on fishing gear impacts reported in 39 separate publications was conducted by Collie et al.(2000). Of the 39 publications none were conducted in mud habitat in North America using an otter trawl. Five North American otter trawl studies were conducted in sand, two in gravel, and one in biogenic habitat. The four studies used to assess otter trawl effects on mud habitats were conducted in Europe and the results for mud habitats were not always consistent, i.e. negative impacts to the total number of individuals and species richness was greater in mud and gravel habitats than sand, however when examining the initial response of individual taxa the more negative impacts occurred in muddy sand, sand and gravel habitats and the least impact was observed in mud habitats.

More recent reviews and studies of otter trawling impacts on mud substrate show few to no short-term study impacts on benthic infauna especially for the net sweep and bottom line components of the otter trawl (Sanchez et al. 2000, Johnson 2002, NE Region EFH Steering Committee 2002). In contrast the heavier trawl doors are known to leave furrows in soft sediment that remain visible for several months. These furrows and depressions are known to focus foraging search patterns by certain benthic or demersal consumers along these topographic features (Burrows et al. 2003). More long-term impact studies have revealed some shifts in the benthic biota of mud substrate from repetitive trawling resulting in a community with fewer species and an increase in the number of small polychaetes (Ball et al. 2000), however, not necessarily lower abundances or biomass. The physical effects of fishing gear smooth bottom gear may be inconsequential and, therefore, undetectable in environments where sediments are eroded regularly and the ambient benthic infauna are already adapted to natural disturbance in the form of bed-load transport of sand and the resuspension of fines by tidal turbulence.

1.2 Project Goals and Objectives

The objective of this study was to have fishermen and scientists in a cooperative effort observe fisheries habitat characteristics before and immediately after repetitive trawling with a smooth bottom net in soft bottom habitat off Scituate, MA, in the western Gulf of Maine. The study sites are in the Massachusetts Bay region of the Gulf of Maine in about 130 ft of water and are know to south shore fishermen (Locus Map, Figure 1.2-1). They include the Mud Hole, an area frequently fished with mobile gear, and Little Tow, which is rarely fished with mobile gear. Because essentially all areas that are suitable for soft bottom trawling in this region are already fished, it is virtually impossible to locate adequate treatment and control sites for comparison. Therefore, we were forced to take the next best alternative – paired sites representing an uncontrolled gradient of trawling pressure.

The purpose of the smooth bottom trawl is to herd fish in to the path of the net to maximize the catch per unit effort. In contrast, the purpose of the ground gear of a hard bottom trawl is to get over irregularities in the substrate. The trawl system used in this study is designed to hug the bottom and is a typical rig used for smooth bottom to catch flatfish (Mirarchi 1998; Figure 1.2-2 from Smolowitz 1998). Impact on the seabed is probably not uniform throughout the smooth bottom trawl system. The doors (or trawl boards) are the heaviest part of the trawl system sweeping about a 5 ft wide path. The ground cables that connect the net to the doors are steel cable strung with 2.5-inch diameter rubber disks or cookies. The third part of the trawl system is the sweep of the net. The sweep is steel chain that is strung with 6-inch diameter cookies. The lower edge of the trawls’ netting is attached to the sweep. The trawl system is about 600 ft in width with the spread of the doors about 200 ft during a tow. A component of the study was to try and identify how impacts vary among components of the smooth bottom trawl system (doors vs. ground cables vs. sweep of the net).

A summary of the specific objectives of the cooperative research effort were to:

Ø Characterize essential fisheries habitat in two ‘soft’ bottom sites historically subjected to different fishing pressure by mobile gear (Mud Hole and Little Tow, Figure 1.2-1) in Massachusetts Bay; and

Ø Document after six repetitive trawls with a smooth bottom net trawl any measurable levels of change in the habitat components of the two sites. Habitat components measured included:

o visual and physical characteristics of the sediment surface,

o infauna,

o epifauna,

o water column parameters,

o and the fish community and their prey.

A number of aspects of the study fell within the fisheries management information needs. In particular the study:

Ø Conducted fishing industry-supported high-resolution sediment mapping in areas of the western Gulf of Maine.

Ø Identified biological communities (pelagic, epifaunal, infaunal) associated with the mapped areas and determined relationships between the ‘soft’ bottom sediment type and these communities.

Ø Examined and compared commercially important fish species and benthic biological communities in ‘soft’ bottom habitat in both heavily and lightly trawled sites and how they respond to the impact of trawling with a smooth bottom trawl net.

Ø Helped define ‘soft’ sediment-prey field associations for managed groundfish species. Current EFH designations are based on presence/absence and relative abundance of each species from historical trawl survey data. Identifying substrate and prey species and their relationship to fish populations is one of the next logical steps in improving EFH designations.

Although this study is just addressing immediate or acute impacts of smooth bottom net trawling in ‘soft’ bottom habitat, the presence of control (“non-trawled”) lanes in the design allows for future studies on the experimentally impacted sites.

1.3 History of the Fisheries at the Selected Sites (Little Tow and Mud Hole) in Massachusetts Bay

Mobile gear fishing began a rapid expansion in New England waters in 1906 when the trawler Spray was constructed by a consortium of Boston fish processors. The new technology quite rapidly replaced the existing longline fisheries due to its efficiency and relative safety yet it generated a storm of controversy due to its bycatch of juvenile groundfish and concern over its effect on the seabed.

Mobile gear fishing did not expand as rapidly in the Gulf of Maine as elsewhere due to the rugged, boulder strewn seabed and the lack of navigational and echosounding technologies. It was probably not until the conclusion of the World War II that mobile gear similar to that in use today came into common use in the Massachusetts Bay area. By 1950 a substantial fleet of draggers from Provincetown, Plymouth, Boston and Gloucester regularly fished Massachusetts and Cape Cod Bays and Stellwagen Bank seeking cod, haddock, flatfish and whiting (S. DeBrusk, in press).

The selection of the study sites for this cooperative research project was sparked by the curiosity of fishermen familiar with Massachusetts Bay region. Both the Mud Hole and Little Tow are historic fishing grounds well known to south shore fishermen. Both historically have yielded abundant catches of yellowtail and winter flounder while codfish appeared seasonally during the late fall and winter months. Despite the similarities in catches and geographic proximity, access to these areas is markedly different.

An area such as the Mud Hole, being both more spacious and connected to other large fishing grounds was frequently fished with several boats spending at least one day per week not uncommon. In contrast, the Little Tow, more isolated, smaller and surrounded by rocky areas was fished infrequently. Often it was the venue for a single, end of the trip “kamikaze” tow where the higher risk of net damage was offset by the possibility of a higher catch in fallow ground.

From post World War II through the mid 1970’s navigation and bottom sensing remained unsophisticated. Many fishermen relied on dead reckoning or the alignment of prominent landmarks to orient themselves. Electronic equipment such as Loran A, a system adapted from aircraft navigation, had a highly variable precision seldom exceeding several hundred meters while available echo sounders provided no more than water depth and a profile of the seabed. By the early 1980’s technology had begun a quiet revolution in the fishing industry. Loran C and subsequently GPS based plotters offered repeatable precision in the tens of meters while, video sounders and sonar provided reliable information on the texture of the seabed both beneath and ahead.

Despite these advances many areas such as the Little Tow remain lightly fished by mobile gear. The enormous pulse of capitalization that accompanied passage of the Magnuson Fishery and Conservation and Management Act (now known as the Magnuson-Stevens FCMA) in 1977 carried an influx of new fishermen into New England. Many of these were fixed gear fishermen who crowded many near shore areas such as Little Tow with gillnets and lobster pots. At times the density of fields of fixed gear created virtual closures that reshaped patterns of historic mobile gear fishing activity.

The 1990’s brought yet another dramatic change in the distribution and intensity of fishing effort with the advent of “rolling closures”, periodic closures of 600 square nautical mile blocks to all commercial gear types capable of catching codfish. The study sites lie within Block 125 that was closed for 6 months (Oct. and Nov. 2000, and Jan. through April 2001) during the 2000 fishing year - May 1, 2000 through April 30, 2001, and for a subsequent seven months (Oct. and Nov. 2001, Jan. through May 2002) during the 2001 fishing year - May 1, 2001 through April 30, 2002. These closures were timed to coincide with the months of maximum groundfish abundance within the study areas resulting in minimal displaced effort being substituted in the intervals when fishing was allowed. Closures do not apply to “exempted gears” e.g., shrimp trawl and scallop dredge. Scallop dredge gear is used at study sites. Fieldwork for this study was conducted during June and July 2001 when the sites, Little Tow and Mud Hole, were open to groundfishing.

1.4 Project Team

The project team included members of the south shore, Scituate and Marshfield, MA, mobile and fixed gear fishing communities and local consulting scientists with extensive experience working in the Massachusetts Bay region of the Gulf of Maine.

Mr. Francis Mirarchi, president of Boat Kathleen A. Mirarchi, Inc. and owner of the 62 ft dragger F/V Christopher Andrew, was the prime contractor for the project and management lead for the fishermen. These fishermen and their vessels included: John Shea owner of the 57 ft dragger, F/V Yankee Rose (Figure 1.4-1 and 1.4-2); Scott MacKinnon owner of the 38 ft gill netter, F/V Lady Irene, and Troy Dwyer owner of the 72 ft dragger F/V Andrea J. II (Figure 1.4-3 and 1.4-4).

CR Environmental, Inc. of Falmouth, MA, was the lead subcontractor managing field operations, data processing, and report preparation. CR Environmental, Inc. has worked closely with the New England fishing community for over 10 years. In 1995, CR was awarded a Fishing Industry Grant (FIG) to train fishermen in the conversion of their vessels’ for oceanographic research. One of that grant’s training seminars was held in Scituate, MA. Mr. Mirarchi played a key role in recruiting fishermen for the project and provided the F/V Christopher Andrew for equipment demonstrations and training. Since that time the F/V Christopher Andrew, Mr. Dwyer’s dragger the Andrea J. II, and other New England fishing vessels chartered by CR Environmental have performed numerous side-scan searches and surveys, water quality surveys, oceanographic mooring deployments, and sediment sampling operations from Maine to New York.

CR personnel supporting this NOAA Cooperative Research project included: John H. Ryther, Jr., oceanographic operations; Christopher Wright, biologist/hydrographer; Andrew Spinale, fisheries; and Charlotte Cogswell, ecologist. Other key technical project personnel included Dr. David Stevenson, now with NOAA/NMFS for fisheries; Dr. Barbara Hecker, an expert in the analysis of marine community structure and quantitative ecology; Dr. Allan Michael, a benthic infauna expert; and Vincent Capone, a biologist and skilled ROV operator.

1.5 Gear Selection

The survey and sampling equipment selected for this NOAA trawl impact study was owned by CR Environmental or fabricated by members of the south shore fishing community. The equipment is designed for shallow (<100 m) bottom habitat mapping, underwater video surveillance, benthic sampling and water quality surveys. It is lightweight, portable, and designed to be used on vessels of opportunity.

Specifically the project equipment included a:

· 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;

· Portable Benthos MiniRover MKII ROV system with high resolution video and still cameras, and strobe;

· Lightweight custom aluminum towed video sled with miniature color video camera, video lights and navigation interface;

· Ted Young grab sampler with stainless steel frame;

· Seabird Seacat CTD system;

· Trimble AG132 and ProXRS DGPS systems; and

· Coastal Oceanographics HYPACK survey software.

Oceanographic support equipment fabricated by former Scituate, MA, fishermen, Bob Stevermen, including: oceanographic winches with sliprings and conductor cables, hydraulic A-frames, and side-mounted lifting davits.

This gear is relatively low in cost compared to ocean mapping multibeam systems and large remotely operated vehicles (ROVs). Specification sheets are provided in (Appendix A).

1.6 Experimental Design

The impact of fishing 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. “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).

An initial reconnaissance survey of the study sites was conducted using side-scan sonar on the 100 kHz frequency and the 100 m range scale, and bathymetry using F/V Christopher Andrew’s shipboard Koden echosounder and Northstar 951X DGPS to identify homogeneous habitats at each site and to document differences in historic fishing activity.

Four non-overlapping, lanes or belt transects (1000 m x 100 m) were selected within each site: 2 experimental (trawled) lanes and 2 temporal control (not experimentally trawled) lanes (Figures 1.6-1 and 1.6-2). Sampling was conducted both pre- and post-trawling (after 6 trawl passes) along or at random stations on each of the experimental and control lanes.

Sampling conducted on all lanes pre- and post trawling included:

· Continuous video coverage with a towed video sled along an entire lane;

· One hundred meter long ROV transects run perpendicular to a lane at 3 random stations to obtain detailed video coverage for viewing biota and physical trawl impacts and collecting high resolution still photographs;

· Benthic grab samples – 3 replicate grabs at each of 3 random stations on a lane for infaunal characterization (up to 3 analyzed per station; only 72 contracted for) and one grab for sediment grain size analysis; and

· CTD casts at each of the 3 random stations on a lane.

At each site, six repetitive trawl tows were conducted along each of the towed experimental transects. The contents of each trawl were assessed in terms of the type of fish, number and weight of catch and bycatch; and the contents of up to 20 stomachs from the two dominant groundfish species, winter flounder and yellowtail flounder, were collected.

Table 1.6-1. Sampling Design

SITE	MUD HOLE				LITTLE TOW
Transects	Experimental		Control		Experimental		Control
Pre-trawling	Lane 1	Lane 3	Lane 2	Lane 4	Lane 1	Lane 3	Lane 2	Lane 4
Video sled - continuous	1	1	1	1	1	1	1	1
ROV transects	3	3	3	3	3	3	3	3
Benthic infaunal samples*	3	3	3	3	3	3	3

TABLE OF CONTENTS