Coonamessett Farm Foundation Dredge Research Program Ronald - - PowerPoint PPT Presentation

Coonamessett Farm Foundation Dredge Research Program

Ronald Smolowitz Matthew Weeks

Pre 1994: Flounder catch in scallop dredges was considered a target; not unwanted bycatch. Research concentrated on ring-size increase to improve scallop selectivity. 1994:Groundfish closed areas on Georges Bank include scallop dredge vessels. 1995: S-K program funds Coonamessett Farm research on larger mesh twine tops to improve fish escapement. 1999: Ten-inch twine top becomes regulation in certain scallop access areas 2002: NMFS becomes aware that turtles are being caught in scallop dredges. 2004: Turtle Chains developed and tested by Coonamessett Farm and VIMS 2005: Forward cutting bar dredge frame designed by Coonamessett Farm to reduce impact on turtles begin to be tested. 2006: The excluder dredge frame underwent a series of successful tests on sea turtle carcasses and at sea trials . Tests demonstrate the need to remove bale bars. NMFS makes chain mats mandatory. 2007: ROV first utilized to observe turtle behavior. CFarm contracts with NEFSC to perform a dredge comparison study of CFarm Turtle Excluder Dredge. 2008:. Field trial results of Cfarm Turtle Excluder Dredge show reductions in fish bycatch rates. 2010: Testing begins on low profile version of the Cfarm Turtle Excluder Dredge. 2011: Continued testing and development of the low profile dredge

Timeline of Scallop Fishery Dredge Bycatch Research

Coonamessett Farm Scallop Dredge Project Summary

• NOAA Grant #

Title Lead Budget

• NA03NMF4540344

Turtle Chain Tests VIMS

• NEFSC Contract

2004 Turtle Video Cfarm $ 25,000

• NEFSC Contract

2005 Turtle Video CFarm

• NEFSC Contract

2005 Panama City NEFSC

• NA05NMF4541293

Turtle Excluder Dredge Cfarm $ 84,400

• NEFSC Contract

2006 Panama City NEFSC

• NA06NMF4540263

Sea Turtle Interaction Cfarm $ 94,282

• NA06NMF4540258

New Dredge Design Cfarm $149,206

• NA07NMF4540029

Field Testing of Dredge Cfarm $ 89,144

• NEFSC Contract

2008 Turtle Run-over CFarm $ 25,000

• NA08NMF4540663

Turtle-Dredge ROV Cfarm $134,624

• NA09NMF4540131

Turtle Oceanography Cfarm $199,929

• NA09NMF4720414

Low Profile Excluder Dredge Cfarm $ 30,000

• Totals

$806,585

Standard New Bedford Sea Scallop Dredge

Fish Excluding Concepts Tested by C-Farm

(1) Mechanical Blocking (1) Mechanical Blocking

• Blocking of Frame Windows

Blocking of Frame Windows

• Toothed Dredges

Toothed Dredges (3 (3) Avoidance Behavior

) Avoidance Behavior

• Tickler Chains

Tickler Chains

• Drop Chains

Drop Chains

• Frame Design

Frame Design

• Rollers

Rollers

(2) Sorting (2) Sorting

• Chain Mat Attachment to Frame

Chain Mat Attachment to Frame

4) Escapement 4) Escapement

• Modified Twine Top Mesh Sizes

Modified Twine Top Mesh Sizes

• Hanging Ratios

Hanging Ratios

• Windows in Twine Top

Windows in Twine Top

• Fish Eyes in Twine Top

Fish Eyes in Twine Top

• Apron length

Apron length

Fish Bycatch Reduction Project

Modifications to Dredge Frame

Challenges to Dredge Modifications

Deck Operations

Turtle Chains

Demonstration of Possible Interaction of Sea Turtle on the Seafloor with a Standard New Bedford Scallop Dredge

Standard New Bedford Dredge C-Farm Excluder Dredge

Development of C-Farm Excluder Dredge Over 4,000 comparison tows conducted Industry currently voluntarily implementing

Examples of C-Farm Excluder Dredge / Sea Turtle Interaction

9 out of 9 encounters were excluded with no injuries observed

Testing of of C-Farm Excluder Dredge on Hard Bottom

Observed Fish Behavior

C-Farm Turtle Excluder Dredge C-Farm Low Profile Excluder Dredge Twine Top

Cfarm Turtle Excluder Dredge Catch Results (N=1632 tow pairs) Species Total Catch % Change Significant (Pt) Scallops 33131 bu 3% 0.000 Skate 131938

• 0.3%

0.000 Monkfish 14378 1% 0.057 Summer fl. 2552

• 10%

0.004 Grey sole 1237 4% 0.265 Yellowtail fl. 10034

• 46%

0.000 Winter fl. 88

• 69%

0.000 Barndoor sk. 1725

• 18%

0.000 Winter sk. 1339

• 20%

0.006 Sand dab 1617

• 48%

0.000 Fourspot fl. 4382

• 20%

0.000 American pl. 305 114% 0.000

Low Profile Dredge

Low Profile Dredge

Low Profile Dredge Catch Results N=32 pair tows Species Total Catch % Change Significant Pt(a=0.05) Scallops 40 bu

• 13%

0.040 Skate 10589

• 88%

0.000 Monkfish 232 11% 0.220 Summer fl. 278

• 55%

0.000 Yellowtail fl. 52

• 8%

0.410 Winter fl. 216

• 122%

0.010 Barndoor sk. 106

• 30%

0.050 Winter sk. 459

• 27%

0.090 Sand dab 578

• 116%

0.000 Fourspot fl. 49

• 72%

0.130

Masthead view of turtle being tracked by ROV

Total number of video hours of turtles followed for >30 minutes = 53.5 hours Total number of turtles recorded for >30 minutes = 23 turtles 7 ROV trips on the scallop fishing grounds during spring/summer/fall 2007-2010

Turtle Behavior Observation Using an ROV

ROV being deployed from scallop vessel

Foraging Dives to Seafloor

Example of Descent Example of Ascent

10 turtles have been observed diving to the sea floor 17 dives to the seafloor have been observed 15 of those dives were foraging dives, 2 were avoidance dives Observed distinct “pre-dive” and “post-dive” behavior Depths of 46 – 70 meters, temperatures of 7-11.5 C, up to at least 38 minutes Often become negatively buoyant at ~30 meters and begin rapid glide

Benthic Foraging

Feeding on crabs Feeding on scallops

1 turtle observed feeding (or attempting to feed) on sea scallops

• n 9 occasions during 2 different dives

Positions of Observed Benthic Foraging

Pelagic Foraging

Example of Potential Avoidance Behavior to Dredge During Haul Back

Social Behavior

Total number of social groups observed = 14

Turtle / Oceanographic Study

Oceanographic Work

Possible Association with “Cold Pool”

Loggerhead Turtle Aerial Survey Study

Satellite Tag Study

16 turtles captured in the scallop access areas and tracked with satellite tags during 2009 and 2010 25 more planned to be tagged during spring 2011

2009 - 2010 Tag Data

2010 – 2011 Tag Data

Dive Patterns and Profiles

Data from Satellite Tags: Synchronized Movements