# Presentation: 688498

## NEFSC/Industry Cooperative Survey Gear Study

**28 October – 6 November, 2002**

- To examine differences in catch rates of the R/V Albatross IV using standard Yankee #36 trawls in two configurations; one configuration that conformed to standard specifications and a second configuration that was known not to meet specifications, including offset trawl warps.

**OBJECTIVE**

- Source Document: Specifications for Construction of NEFSC Standard #36 Bottom Trawl

## SAMPLING AREAS

-   Specific areas determined onboard the ship
- 	shallow - approximately 87 m (47.5 fm) in depth
- 	mid-depth - approximately 139 m (76 fm)
- 	deep - approximately 198 m (108 fm)
-   Areas selected in order to cover a range of depths and to sample
-     as many species as possible

**SAMPLING AREAS**

- Original plan was to sample 2 areas in 1 depth zone then 2 areas
-    in a second depth zone
- Weather prevented occupation of 4 areas; therefore a third
-    ‘shallow’ area was sampled

## NEFSC/Industry Cooperative

**NEFSC/Industry Cooperative**
**Survey Gear Study – Part I**
**28 October – 6 November, 2002**
**Location of Sampling Areas**

**Area 1**

**Area 3**

**Area 2**

***Closed Area I***

**100m**

## BOTTOM PHOTO from NW CAI (Area 1)

**BOTTOM PHOTO from NW CAI (Area 1)**

- Albatross Cruise 99-08, July 1998, Site I2
- Image provided by Page Valentine, USGS, Woods Hole Field Center

## BOTTOM PHOTO from NE CAI (Area 2)

- Albatross Cruise 99-08, July 1998, Site I2
- Image provided by Page Valentine, USGS, Woods Hole Field Center

**BOTTOM PHOTO from NE CAI (Area 2)**

## STATION SELECTION

-   Each area was subdivided into 25 blocks, each 1-minute by 1-minute
-   Each block was further subdivided into four quadrants
-   Sixteen blocks were chosen, the maximum possible number of
-     stations that could be performed during one 24 hour period,
-     using uniformly distributed random numbers
-   Stations were then placed in a randomly selected quadrant within
-    each block

**STATION SELECTION**

## GRID USED TO POSITION TOW STARTING POINTS

**GRID USED TO POSITION TOW STARTING POINTS**

## TOWING PROTOCOLS

-   Order of gear configurations used determined by coin toss
-   One randomly chosen gear configuration was used for 24 hours,
-     then configurations switched and tows made at the same locations
-     the following day
-   Tows offset by approximately 1 additional hour to account for tide
-     and light conditions
-   Direction of tows determined by the Captain of the F/V Sea Breeze
-   Constant scope used for all tows within an area.  Scope chosen
-     was that used for the deepest likely depth in an area

**TOWING PROTOCOLS**

## SCOPE AND TRAWL WARP OFFSETS USED IN EACH SAMPLING AREA

## ‘Optimal’ (OPT)

-    the specifications by industry representatives
-   Doors used (Pair #38) were inspected by industry representatives
-    to meet tuned door specifications
-   Backstraps used were fitted with swivels (with the appropriate
-    number of links removed to maintain standard specification) to
-    ensure that there were no twists in the chain while the net was
-    fishing
-   Even trawl warps; re-measured and certified the day of sailing

***‘******Optimal’ (OPT******)***

**GEAR SPECIFICATIONS - R/V Albatross **

## ‘Worst Case Scenario’ (WCS)

**GEAR SPECIFICATIONS - R/V Albatross **

-   Net #14, used during the 24-27 October, 2002 ‘video cruise’
-    (the last 4 days of Leg II of AL 02-09, Autumn Bottom Trawl
-    Survey)
-   Pair #37 doors considered to be performing poorly during the
-    ‘video cruise’
-   Backstraps with no swivels and intentionally twisted 2 times
-   Trawl warps offset to match the mis-marked warps used during
-    2001-2002 surveys

## GEAR SPECIFICATIONS - F/V Sea Breeze 

-   16” (with 12” at wings) rockhopper footrope with 2” cookies
-   110' sweep
-   30 fm groundcable used in Area 1
-   50 fm groundcable used in Areas 2 and 3
-   2.4” (6 cm) mesh codend liner

**GEAR SPECIFICATIONS - F/V Sea Breeze **

## GEAR SPECIFICATIONS

**GEAR SPECIFICATIONS**

## Location of Paired Tows

**Location of Paired Tows**

**Area 1: NW Closed Area I**
**‘****Optimal’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 1: NW Closed Area I**
**‘****Worst Case Scenario’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 1: NW Closed Area I**
**29-30 October, 2002**

## Location of Paired Tows

**Location of Paired Tows**

**Area 2: East of Cape Cod**
**‘****Optimal’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 2: East of Cape Cod**
**‘****Worst Case Scenario’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 2: NW Closed Area I**
**31 October-3 November, 2002**

## Location of Paired Tows

**Location of Paired Tows**

**Area 3: NE Closed Area I**
**‘****Optimal’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 3; NE Closed Area I**
**‘****Worst Case Scenario’ Configuration**

## Location of Paired Tows

**Location of Paired Tows**

**Area 3: NW Closed Area I**
**3-5 November, 2002**

## SAMPLING PROTOCOLS

-   Catch sorted by species and weighed (nearest 0.001 kg) using
-    motion compensated digital scales
-   Lengths of all fish measured (nearest cm)
-   All catch and biological data were recorded using the shipboard
-    automated data entry system
***Sea Breeze***
-   Catch sorted by species and weighed using same scales
-   Individual fish lengths were taken on a subsample of the catch
-     when time allowed
-   Catch weights were recorded on standard fisheries observer program
-    logsheets and transmitted to the Albatross
-   Catch numbers and individual fish length data were also recorded on
-    fisheries observer program logsheets and processed at the Woods
-    Hole Laboratory the day after the cruise ended

**SAMPLING PROTOCOLS**

## SUMMARY OF TOWS CONDUCTED 

**IN EACH SAMPLING AREA**