Tab E, No. 4(a) Minimizing Red Snapper Discard Mortality Judd - - PowerPoint PPT Presentation

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Oct 19, 2023 49 likes •355 views

Tab E, No. 4(a) Minimizing Red Snapper Discard Mortality Judd Curtis, Ph.D. & Greg Stunz Ph.D. Research Objectives 1) Es&mate mortality of discarded Red Snapper using acous&c telemetry 2) Compare performance of release tools to

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Minimizing Red Snapper Discard Mortality

Judd Curtis, Ph.D. & Greg Stunz Ph.D.

Tab E, No. 4(a)

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Research Objectives

1) Es&mate mortality of discarded Red Snapper using acous&c telemetry 2) Compare performance of release tools to mi&gate discard mortality 3) Determine temperature (seasonal) and depth effects and interac&ons 4) Assess angler “buy-in”

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Harvested 62% (6,714) Discarded alive 33% (3,632) Discarded dead 5% (569)

“iSnapper” Discard Mortality

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Barotrauma (Pressure-related injuries)

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Rapid Recompression Devices

Coupled with heavy weight, descends

discarded fish back to depth

Various manufacturers and types

– SeaQualizer – Black@p – Shelton hook – Milk crates

Successfully reduce discard mortality

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Vent/Recompress Non-Vented

“In the Lab...”

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25 50 75 100

Survival (%)

Drumhiller et al. 2014: Mar Coast Fish

Mortality: Laboratory Results

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1) Field condi&ons inherently more variable 2) Widely variable depth/seasonal effects in field? 3) Stress associated with capture 4) Predators

Controlled Laboratory Condi&ons Field Condi&ons vs

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Survivor Delayed Mortality

Solu&on: Acous0c Telemetry

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14 days aHer tagging

Lab Tagging Trials

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Fate?

Survivor Delayed Mortality Emigrant

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BREP: Design - Ongoing Field Studies

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Field Survival (50m)

Cur&s et al. 2015: Mar Coast Fish

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Capture Depth vs Mortality

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n = 20 n = 24 n = 24 0.1 0.2 0.3 0.4

0m 30m 60m Impairment Score

ANOVA P < 0.001

Barotrauma Impairment Scoring

Drumhiller et al. 2014: Mar Coast Fish

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Barotrauma Impairment

n = 1609

Barotrauma Impairment Scoring

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98’

30 m

130’

40 m

262’

80 m

197’

60 m

164’

50 m

33’ 65’ 43’ 87’ 55’ 109’ 131’ 66’ 174’ 87’

1/3 1/3 1/3 1/3 1/3 2/3 2/3 2/3 2/3 2/3

SQ30 SQ70 SQ70 SQ70 SQ50 SQ100 SQ100 SQ50 SQ150 SQ150

Seafloor

NFWF -Approach and Design: Sweet spots, Release Depth, Tools

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1 2 3 4

Catch and Release System for Scoring Barotrauma Outcomes CRSSBO

SeaQualizer Black&p

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Dolphin Released snapper

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Acoustic Deterrent Device

Percent of time dolphins Remained in area

0% 25% 50% 75% 100% Active Inactive

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Preliminary Results (NFWF Study)

30 m 40 m 50 m 60 m 80 m

Observa@ons 62 56 52 53 57 Acous@c tagged 14 12 14 14 15 Fight @me (s) 53 76 91 97 104 Deck @me (s) 114 110 145 161 98 Mean TL (mm) 457 517 535 526 473 1/3 survival 95% 79% 93% 71% 32% 2/3 survival 100% 84% 64% 75% 56% BoZom survival 95% 76% 63% 64% 11% Overall Survival 96% 80% 73% 70% 37%

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Distribute SeaQualizers to

recrea&onal anglers à Partnership with FishSmart

Survey for feedback on descender

device use

Ride-along trips with charters and

recrea&onal anglers

It works, but... will anglers use them?

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Distribution of Participants in the FishSmart Descender Distribution and Education Project

AL FL GA LA MS NC SC TX Total Total 252 380 81 69 25 31 69 242 1,149

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* Exposure: On average: 8 months usage, on 15 fishing trips, releasing ~ 75 fish ea. total. * Increased Awareness: 72% had little or no knowledge of descender devices prior to participating * Effective Education: 67% found Best Practices materials helpful to improving the way that they release fish * Changed Behavior: 76% are now likely to use a descender device

Preliminary Survey Results*

* Survey conducted jointly with Texas A&M University-Corpus Christi , Harte Research

Institute for Gulf of Mexico Studies

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* Changed Preferences: 70% prefer to descender devices over venting tools * Improved Perceptions; 78% believe descender devices would be helpful

r very helpful to reducing discard mortality.

* Extended Communication: 95% talked with, or involved other anglers in, the use of descending devices. * **Additional results to follow**

Preliminary Survey Results

(continued)

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1) Descender Devices work 2) Strong seasonal effects on mortality 3) Depth (of course) an important factor in survival 4) High benefits of descending devices up to a depth “Tipping point” - ~ 180’ 5) Angler acceptance 6) Showing promise not just in Gulf by many other areas

Take Home Messages:

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Acknowledgments

Jason Williams Matt Streich Alex Tompkins David Norris Karen Drumhiller Judd Curtis, Ph.D.