Determining the post release mortality rate and best capture and handling methods for haddock discarded in Gulf of Maine recreational fisheries

Transcription

1 Determining the post release mortality rate and best capture and handling methods for haddock discarded in Gulf of Maine recreational fisheries John Mandelman; Connor Capizzano; Doug Zemeckis; Micah Dean; Bill Hoffman; Nate Ribblett; Hugues Benoît; Nick Buchan; James Sulikowski; Steve Cadrin Photo credit: Isaac Benaka

2 Introduction Background Team leveraged vast experience in acoustic telemetry, recreational groundfish fisheries, and tactical/analytical methods to investigate discard mortality (DM) Recently funded studies on cod and cusk in this fishery

3 Introduction Recreational Gulf of Maine Groundfish Fishery Head/party boats For Hire Vessels Charter boats Primary Species Atlantic cod (Gadus morhua) Haddock (Melanogrammus aeglefinus) Private Vessels Pollock (Pollachius virens)

4 Introduction Gulf of Maine Haddock Recreational haddock catches ranged from 29% to 68% of total annual removals [by weight] over last decade Recreational discards Recreational landings Commercial discards Commercial landings NEFSC (2014)

5 Introduction Recreational fisheries management and discard mortality Increasing number of groundfish discards in recent years due to shifting management measures DM assumption influences possession and size limits, among other reg. factors Assumes 50% DM rate for haddock in recreational fishery But NO DIRECTED DISCARD MORTALITY RESEARCH

6 Introduction Study objectives 1. Estimate longitudinal haddock DM in Gulf of Maine recreational fishery 2. Establish optimal catchand release guidelines for this fishery

7 Methods Field protocols Haddock captured using standardized rod and reel setups and rigs Range of angler experience levels employed (n = 75 anglers; 1:1 tackle split in effort/trip)

8 Methods Field protocols All capture related variables recorded (i.e. biological, environmental, and technical) Injury score index applied

9 Methods Study Design 1. Large scale indexing of haddock haddock 2. Telemetry to validate index in subsample 3. Use index to estimate mortality on large scale to develop best capture and handling methods? variables Estimate DM alive Sample Mortality n=2,442 n=156 dead Subsample????????? Fishery scale DM estimate Best capture andhandling methods

10 Methods April October 2015

11 Methods Discerning live vs. dead haddock: Revised approach Discriminant function: finds differences between the vertical and horizontal movement of positive and negative control haddock. Positive (i.e. known alive) n = 13 Negative (i.e. known dead) n = 3

12 Methods Discerning live vs. dead haddock: Revised approach Discriminant function is applied to post release detection intervals for each fish to determine if and when a mortality occurred

13 Methods Analytical methods: Survival model development Assessed covariates (a priori) o Angler experience o Handling time o Tackle type o Capture depth o Temperature difference o Length class o Month of capture o Injury score o Season o Fight time o Total length Maximum likelihood and step wise forward model selection procedures Only selected model with lowest AICc score

14 Methods Analytical methods: Survival model development Season and total length (TL) still influence survival

15 Methods Analytical methods: Survival model development Low sample size of small haddock in the fall Model issues Cannot predict when fishing mortality ends Forces lines to be parallel, misjudges large haddock survival

16 Methods Analytical methods: Survival model development Scenario 1 Scenario 2 Large haddock ( 43.2 cm) Acoustic and traditional tagging data All haddock (< or 50 cm) Acoustic data only

17 Methods Analytical methods Fishery scale DM rate estimate Monte Carlo bootstrap simulations Survival model results MRIP surveys Discard length distribution Number of discards Season and length specific DM rates Number of alive discards by season and length class

18 Results Terminal tackle catch rates Handling 59 sec Handling 69 sec Significant difference (p <<0.001) between handling times for haddock caught on bait and jig.

19 Results Injury score observations Higher foul hooking rate (16X), and rate and severity of injury when haddock caught by jig

20 Results Transmitter emigration 121 recaptures to date (4.9% return rate in months tags have been at liberty)

21 Results Survival analyses: Results from revised analysis All mortality within first three days No M was observed

22 Results Survival analyses: Results from Scenario 1 Acoustic Size groups are < and 43.2 cm Season impacts survival of large fish ( 43.2 cm)

23 Results Survival analyses: Results from Scenario 1 Traditional tags Season Length class Recapture (#) Total (#) Ratio (Recap/Total) Spring <43.2 cm Spring 43.2 cm Fall <43.2 cm Fall 43.2 cm Ratio comparisons Relative survival Spring vs. fall (Small haddock) Spring vs. fall (Large haddock) Large vs. small (Spring) Large vs. small (Fall) Assumes equal recapture times and all fishing related impacts had ceased.

24 Results Survival analyses: Results from Scenario 1 Combined Mortality Rate Spring Fall Large 18% 53% Relative mortality difference +21% +24% Size groups are < and 43.2 cm Small 39% 77% Season impacts survival of large fish ( 43.2 cm)

25 Results Survival analyses: Results from Scenario 2 Size groups are < and 50 cm Season and TL still impacts survival of fish

26 Results Survival analyses: Results from Scenario 2 Mortality Rate Spring Fall Large 11% 46% Small 32% 74% Size groups are < and 50 cm Season and TL still impacts survival of fish

27 Results Fishery scale DM rate estimate: Number of discards by season Split MRIP survey waves into season via water temperature Estimated number of alive releases by season Water temperate at surface (2 m) and seafloor (50 m) for the Massachusetts Bay (A) buoy in 2015

28 Results Fishery scale DM rate estimate: Number of discards by length class Recreated length distributions for each season Estimated number of alive releases in each length class Minimum size length for 2015

29 Results Fishery scale DM rate estimate: With survival results for each season and length class: Spring Fall Spring Fall DM rate estimates Large Small Large Small 2015 MRIP total haddock discards Scenario 1 65% (95% CI: 50 81%) Scenario 2 63% (95% CI: 51 74%)

30 Discussion Conclusions As projected, injury severity & rate higher for jig Haddock length, season sig predictors of DM Smaller haddock = higher DM in the fall Valuable for consideration in management decisions

31 Discussion Analytical considerations Mortality determinations Use of traditional tag data o Coarse analysis o Reporting rates differences Fishery scale DM estimate o Sampling waves to seasons o Estimate dependent on discard numbers

32 Discussion Industry involvement Industry collaborators crucial to all phases, and authenticity of results Primarily driven by desire for reliable data to inform management Support from recreational fishing industry Project has benefited from open dialogue between scientists, industry partners, and fishery managers

33 Discussion Latest management applicability 50% DM assumption still employed but not yet validated, DM rate influences more than just haddock Policy options are quite sensitive to DM estimates. The bioeconomic model could be re parameterized and rerun for the 2018 fishing year (Lee at al., 2017) Possible inclusion of Gulf of Maine haddock for 2017 SAW (DM update akin to cod?)

34 Discussion Next Steps Finalize survival analyses and fishery scale DM rate Establish optimal fishing and handling practices To apply results, continue engaging management, industry, etc.

35 Acknowledgements Funding provided by the New England Fishery Management Council via the Northeast Consortium, as well as the NOAA Saltonstall Kennedy Grant Program Captain Les Eastman and the captains, mates and staff of Eastman s Docks in Seabrook, NH Captain Thomas Orrell and the captains, mates and staff of the Yankee Fleet in Gloucester, MA Steve de Neef (photos) Dr. Mike Armstrong (MADMF) Dr. Mike Palmer (NEFSC) Numerous volunteer anglers who helped with the field work This study was sanctioned by the New England Aquarium s Institutional Animal Care and Use Committee (Protocol # ) Photo credit: Isaac Benaka

36 Notable outreach to date: GOM recreational fishing community and general public 8pg article in On the Water magazine (Oct 2015) Article in 2016 Mass Saltwater Recreational Fishing Guide AP piece that was picked up by >90 outlets nationwide Other articles in Cape Cod Time, Gloucester Times, Saving Seafood blog, NEAQ blogs Featuring photographs taken by professional marine wildlife photographer/videographer, Steve de Neef

37 Notable outreach to date: Scientific community and management bodies Presented in Science-Industry Partnerships theme session at ICES Annual Science Conference, 2015 Presentation in symposium for DM and its estimation at the 2016 American Fisheries Society s Annual Meeting Accepted presentations for upcoming World Recreational Fishing Conference (2) and the American Fisheries Society s Annual Meeting (1). Regular communication on project progress with members of NEFMC Recent presentation for NEFMC s RSC meeting in April 2017 Ongoing educational opportunities for graduate and undergraduate students at surrounding universities and colleges including: -Spatial ecology of haddock -Understanding angler motivations and behavior in this fishery

38 Future Outreach Distribute results to NEFMC and various divisions in NOAA s Greater Atlantic Regional Fisheries Office and Northeast Fisheries Science Center Peer-reviewed publication in ICES Journal of Marine Science Second article in On The Water magazine Presence the upcoming New England Saltwater Fishing Show 2018 MADMF Saltwater Guide MADMF and NEAq websites/social media Online message boards Presentation at Stellwagen Bank Charter Boat Association and other regional clubs Distribute results using existing industry collaborations (Eastman s, Yankee) and other for-hire vessels and websites

39 Methods Discerning live vs. dead haddock: Original Approach Mortality algorithm; uses vertical movements (V9P, V13P tags; 3 negative controls) Tide adjusted depth (m)