Derelict crab trap removal and prevention in southern New Jersey coastal bays: big implications for smaller scale systems

Transcription

1 Derelict crab trap removal and prevention in southern New Jersey coastal bays: big implications for smaller scale systems Principal investigators: Mark Sullivan, Steve Evert, Pete Straub, Melanie Reding, Kaitlin Gannon, Fred Akers NJ commercial crabber partners: Karen and Warren Unkert, Phil Andersen, George Leeds, Al Kurtz, Joe Buzby, Bob Wilkin Stockton Marine Field Station support: Nathan Robinson, Elizabeth Zimmermann, David Ambrose Stockton undergraduate students: CJ Janiszewski, Brandi Lewis, TJ Johnson, Ryan Harner, MARS 3307 Fisheries class NOAA support: Tom Barry, Keith Cialino, Jason Rolfe

2 Background (DFG in shallow coastal bays) Crab pot loss undocumented in smaller estuarine systems Occurs where boating intersects with crabbing Shallow waters with mixed / soft bottom types a challenge Potential for science / industry partnerships

3 Objectives of NOAA-funded work Objective 1 Identify ghost pots with scientific-grade side-scan sonar Map hot spots and create waypoint files for recovery Objective 2 Train commercial crabbers on low-cost sonar use and shallow water recovery from small boats (<28 ) Recover ghost pots - identify bycatch species Recycle and re-use fishable pots and parts Objective 3 Identify opportunities to increase recovery efficiency Educate boaters, recreational and commercial crabbers

4 Methods overview 5 step process 1. Identify 2. Survey 3. Transfer 4. Train 5. Recover

5 Identify 1. Identify where boating and buoyed-fishing intersect Multiple marinas High boating traffic Significant commercial or recreational effort with buoyed pots

6 Survey 2. Survey with professional-grade SS sonar; ID hot spots Commercial sonars can survey swaths >100m Better imaging increases confidence in target ID Position data is better

7 Klein 3900 side-scan sonar example

8 Transfer 3. Transfer waypoints to low-cost sonar on recovery boats 100 m swath 20 m swath

9 Train 4. Train your recovery teams, preferably industry partners Low-cost sonar training Pre-set instruments Limit options Understand images On-the-water training Increase recoveries / hour by avoiding lengthy data sheets

10 Basic data collected in field by commercial partners Additional data collected on land with students / volunteers

11 5. Recover, recycle, re-use Recover

12 Recovery tool examples see the target Mark the target Single Grapples, 5-8lb. Daisy Chain of Hooks

13 See, mark with buoy, snag See a strong image >> call out the distance & toss a surface marker Approach marker 1. Deploy longer daisy chain of hooks OR 2. Throw individual grapples immediately upon seeing on sonar

14 See and snag on the fly (best case) See a strong image close enough to boat >> call out the distance & toss the grapple (pull boat out of gear) Be ready with grapples use long line at least 6-8x water depth Rigging tip; consider a bow-mounted transducer for recovery

15 Humminbird side-imaging example

16 Three keys to success 1. Conduct broad professional side-scan sonar surveys Identify hot spots to increase recovery efficiency 2. Understand recovery challenges of your shallow water system Know your bottom type are your pots stuck in the mud? Small boats >> low speed>> don t rip and tear 3. Partner with commercial community Train them on low cost sonar use; hire them to help ($350+/day) Trained partners prevent future loss through in-season sonar use

17 Coastwide results Forked River Oyster Creek Waretown Barnegat Mill Creek Cedar Run Mullica River Great Bay Estuary Reed s Bay Absecon Bay Commercial crab trap (83%) Scull Bay Lake s Bay Great Egg Harbor Estuary Recreational crab trap (13%) Jenkins Sound Wildwood Sea Isle City to Stone Harbor Great Sound Peck Bay to Ludlum Bay Regional snapshot 65K Benefits to SNJ commercial crabbing industry 400K ~ Knowledge transfer funding to new partners Fish / eel pot (2%) Whelk (1%) Scanned Pots ( n = >4400) Recovered Pots ( n = >2200) Other (1%) grill pictured

18 Predicting areas of future loss

19 Knowledge transfer to other industries Salt Meadow Oyster Farm 10K in gear lost in ice flow Relocated with Klein 3900 / recovered with Humminbird unit NOAA-funded crabber partners assist with recoveries

20 Funding provided by For More Information