Gear Study on R/V Albatross IV Catch Rates

1. NEFSC/Industry Cooperative Survey Gear Study 28 October – 6 November, 2002 OBJECTIVE 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. Source Document: Specifications for Construction of NEFSC Standard #36 Bottom Trawl

2. SAMPLING AREAS • General sampling areas provided by industry • 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 • 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

3. Area 2 100m Area 1 Area 3 NEFSC/Industry Cooperative Survey Gear Study – Part I 28 October – 6 November, 2002 Location of Sampling Areas Closed Area I

4. 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

5. 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

6. STATION SELECTION • The areas were 5-minutes by 5-minutes (approximately 25 nm2) • 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

7. 4.75 4.25 3.75 3.25 2.75 2.25 1.75 1.25 0.75 0.25 GRID USED TO POSITION TOW STARTING POINTS

8. TOWING PROTOCOLS • Each area sampled for 48 hours • 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

9. SCOPE AND TRAWL WARP OFFSETS USED IN EACH SAMPLING AREA

10. GEAR SPECIFICATIONS - R/V Albatross ‘Optimal’ (OPT) • Net #21, constructed prior to the experiment and inspected to meet • 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

11. GEAR SPECIFICATIONS - R/V Albatross ‘Worst Case Scenario’ (WCS) • 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

12. GEAR SPECIFICATIONS - F/V Sea Breeze • Standard 6" mesh groundfish net • 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

13. GEAR SPECIFICATIONS

14. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 1: NW Closed Area I ‘Optimal’ Configuration

15. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 1: NW Closed Area I ‘Worst Case Scenario’ Configuration

16. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 1: NW Closed Area I 29-30 October, 2002

17. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 2: East of Cape Cod ‘Optimal’ Configuration

18. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 2: East of Cape Cod ‘Worst Case Scenario’ Configuration

19. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 2: NW Closed Area I 31 October-3 November, 2002

20. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 3: NE Closed Area I ‘Optimal’ Configuration

21. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 3; NE Closed Area I ‘Worst Case Scenario’ Configuration

22. Albatross IV Tows Sea Breeze Tows Location of Paired Tows Area 3: NW Closed Area I 3-5 November, 2002

23. SAMPLING PROTOCOLS • Albatross • 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

24. SUMMARY OF TOWS CONDUCTED IN EACH SAMPLING AREA