Effects of escape from fishing gear on sockeye salmon migration and survival. David Moulton University of British Columbia

Transcription

1 Effects of escape from fishing gear on sockeye salmon migration and survival David Moulton University of British Columbia

2 Outline Fraser River sockeye management Research application and methods 2017 summer sockeye project 2018 late Shuswap sockeye project Summary

3 Major themes: Linking science to conservation & management Physiology Behaviour Population ecology Ecosystem ecology Habitat data (limnology, oceanography) Life history Basic science Applied science Fisheries exploitation data Applied life history data Human dimensions: socio-economic data Protecting populations & habitats Restoring populations & habitats Conservation Management Harvest regulations Managing fisheries & habitats

4 Fraser River Sockeye Salmon Culturally, economically important In-river migration distance ( km) Huge geographic scope High potential of encountering fisheries

5 Fraser Sockeye Mgmt is Complicated! 271 separate populations 4 run timing groups Early Stuart Early Summer Summer Late 14(!) life history combinations

6 Fraser River Salmon Management Fisheries and Oceans Canada (DFO) Pacific Salmon Commission (PSC) Pre-season forecast In-season return assessment Post-season reporting Priorities: 1) Escapement 2) First Nations food, social, ceremonial (FSC) Lots of attention and effort!

7 Fish Enumeration Test fishing - marine/freshwater - stock ID Hydroacoustics PSC.org Spawning grounds hydroacoustics, mark-recapture, weirs, visual surveys

8 Escapement Discrepancies Difference between estimates (DBE) - Fish lost during migration Causes? E.g. natural mortality, unreported catch, estimation error Avoid: insufficient escapement (read: not enough survivors) or foregone catch (read: too many survivors) Bottomline: How many fish will die along the way?

9 Management Adjustment Models Management Adjustment (MA) Additional fish allowed to migrate How many? Management Adjustment Modeling Quantify factors impacting survival during upriver migration E.g. temperature, discharge Adjust harvest to account for anticipated mortality

10 What Kind of Fishing Occurs? Sockeye fisheries: Test fisheries, First Nations fisheries Commercial fisheries? Recreational angling? Ocean methods: troll, gillnet, purse seine River methods: gillnet, beach seine, Hook-and-line, dipnet, fish wheel, weir

11 Gillnet injured sockeye at Seton River Fence (proportion of total captured) Most Injuries from Downriver Fisheries! More gillnets in river more injuries Sockeye rarely released Escape is prevalent Impacts? Adam Kanigan, MSc research Gillnet Fishing Effort Lower Fraser River (hours per week)

12 Potential Fishery Impacts Non-retention: intentional release (bycatch) or escape Stress Mucous loss Injury Delayed mortality Synergistic stressors? Infectious agents Temperature

13 Outline Fraser River sockeye management Research application and methods 2017 summer sockeye project 2018 late Shuswap sockeye project Summary

14 Applied Conservation Research! Adult freshwater spawning migration critical stage Quantify effects of: injury, infection, and temperature Key outcomes: Migration fate, spawning success Goal: inform improved run management Federal funding (NSERC) and collaboration (DFO)

15 Holding study Controlled conditions Repeat sampling Fate known; terminal samples Gamete collection Tandem Studies Radio Telemetry Natural migration experience Physical test

16 Methods Common to Each Study Catch fish using beach seine Fisheries simulation at riverside Tag/release or transport to holding facility Sample for infection screening, gene expression analysis

17 Gillnet ( Tight )

18 Gillnet ( Loose )

19 Beach Seine

20 Trough Sampling PIT tag / radio tag, condition assessment, gill sampling PIT tag Radio tag

21 If you catch Radiotagging a sockeye salmon, please Sockeye check to see if the fish is tagged as follows: Stomach Stomach cavity External tag ID atch a fish or estions t this please leave a ge for Reid: Antenna Flexible antenna (flexible) Radio transmitter Radio transmitter with antenna OR tag with no antenna Fraser River sockeye salmon are being studied using location transmitters that are inserted into the stomach cavity. Tagged fish can be identified by an external fluorescent yellow floy tag located behind the dorsal fin, as shown above. If you capture and retain a tagged fish or recover a carcass with a transmitter, please remove the

22 Riverside Condition Assessment Scale Loss Wounds Net Marks Sea Lice (live/scars) Study Design Fin Damage Gill Quality Injury from Gear Reflex Action Mortality Predictors (RAMP)

23 Cultus Lake Salmon Laboratory (DFO)

24 Holding Study Methods Ten 8,000-L flow-through tanks 25 fish per tank (treatments mixed) Actual migration temp. (real-time adjustment) Weekly gill biopsies Terminal sampling

25 Telemetry Station Setup

26 Tag Recovery

27 Outline Fraser River sockeye management Research application and methods 2017 summer sockeye project 2018 late Shuswap sockeye project Summary

28 2017 Study design Summer run populations (e.g. Chilko, Stuart - August) Holding: D. Moulton; Tracking: A. Reid (Carleton U.) Does gear type or nature of entanglement influence: Reflex impairment Injury Infection Survival Additionally: Effects of temperature or degree of handling?

29 Study Design Group 1 Captured: August N=200 Study Design Group 2 Captured: August N=50 Net simulations: Tight gillnet Loose gillnet Beach seine Biopsy control Control (no gill biopsy) Net simulations: Tight gillnet Loose gillnet Beach seine Control Less handling No condition assessment, No gill biopsy

30 Fish Collection Peters Band (Sto:lo Nation) fishers August 8-22, holding; 385 tagged & released Escape simulations: - Beach seine - Tight gillnet - Loose gillnet

31 Fish Collected were Chilko and Stuart Lake stock Stuart Lake Capture site Chilko Lake Pacific Ocean Holding site Raby et al. 2015

32 Gillnet Treatments Caused Injury Injury: 0=none, 1=mild, 2=moderate, 3=severe Simulated gillnet caused more injury than simulated seine n = 40 n = 40 n = 40

33 Impairment Testing (RAMP) Reflexes tested: 1. Tail grab response 2. Body flex 3. Head complex (proper gilling) 4. Vestibular-ocular response (eyes tracking) 5. Orientation 0 = unimpaired, 1 = impaired Score 0.4 predictive of delayed mortality

34 Low Impairment Following Treatments Scale: unimpaired = 0 1 = fully impaired Delayed mortality not expected based on initial impairment Delayed mortality threshold n = 40 n = 40 n = 40 n = 40 n = 40

35 River Temperature at Hope, BC ( ) Group 1 capture Group 2 capture Initial Temperature Differed for Capture Groups 21 Study Design Natural mortality 2.5x 18 Elevated stress /5 8/7 8/9 8/11 8/13 8/15 8/17 8/19 8/21 8/23 8/25 Source: Water Survey of Canada Date (m/d)

36 Tank Water Temperature ( ) Similar Thermal Profiles for Capture Groups Group 1 Group 2 19 C 18 C Accumulated Thermal Units ( C/Day) Group 1 = Group 2 = Days

37 Proportion Surviving High Mortality for All Treatments (Group 1) Study Design Control, n = 40 Biopsy control, n = 40 Loose GN, n = 40 Tight GN, n = 40 Seine, n = 40 Delayed Mortality 5 days 10 days 17% 85% 32% 80% 52% 90% 37% 67% 30% 87% Days Post Capture

38 Proportion Surviving Moderate Mortality for All Treatments (Group 2) 1 Study Design Delayed Mortality 5 days 10 days Control 0% 31% Control, n = 14 Loose GN, n = 12 Tight GN, n = 12 Loose GN Tight GN 0% 23% 0% 25% 0 Seine, n = Days Post Capture Seine 0% 58%

39 Proportion Surviving Survival Differed by Capture Group Days Post Capture Group 1, n = 200 Group 2, n = 50 Kaplan-Meier survival analysis Log-rank test *p < Delayed Mortality 5 days 10 days Group 1 34% 82% Group 2 0% 34% (Less handling)

40 2017 Preliminary Conclusions Study Design High temp + handling high delayed mortality Temperature trumped treatment Degree of handling likely contributed to mortality - Group 2 (handled less) had greater survival

41 Proportion of fish Telemetry Study - Treatment Affects Survival *** X 2 (6, 368) = 35.9, p<0.001 Migration survivor River mortality Imminent mortality Andrea Reid Carleton University Control Biopsy control Loose gill net Tight gill net

42 Outline Fraser River sockeye management Research application and methods 2017 summer sockeye project 2018 late Shuswap sockeye project Summary

43 2018 Study Design Late run (e.g. Shuswap - October) Holding & Tracking: D. Moulton Does gillnet entanglement duration impact: Injury Infection Reproduction Survival Additionally: Intergenerational offspring effects?

44 Fish Collection and Tagging Sts ailes Nation fishers September 17-26, holding; 361 tagged & released Gillnet escape simulation 0-37 minute duration

45 Fish Collection and Tagging Sts ailes Nation fishers September 17-26, holding; 361 tagged & released Gillnet escape simulation 0-37 minute duration

46 Fish Tracked Using Radiotelemetry

47 Back to Cultus - 1 Month Holding Study Weekly repeat gill biopsies

48 Injury Severity by Entanglement Duration Longer entanglement time increased injury severity

49 Fungus Development by Treatment Gillnet entanglement led to increased fungus development

50 Proportion Surviving Greatest Mortality for Gillnet Treatment Control, n=50 Biopsy control n =50 Gillnet n = 145 Total Mortality Control 4% Biopsy Control 12% Gillnet 58% Days Post Capture

51 Proportion Surviving Greater Mortality for Gillnet Females Total Mortality Females Males Males 37% Females 74% Days Post Capture

52 Tracking Study Results

53 Migration Fate 30 Fish harvested (mostly Kamloops Lake fishery) 145 fish not detected at spawning grounds 184 fish reached spawning grounds Adams Lower Shuswap Eagle n = 82 n = 79 n = 23

54 Survival by Treatment and Sex Treatments impact female survival

55 Survival by Duration No clear trend in influence of entanglement duration on survival

56 Survival by Duration Females Males

57 2018 Preliminary Conclusions Study Design Gillnet entanglement resulted in greatest mortality, especially for females Gillnet entanglement caused increased fungus development Increasing entanglement duration resulted in more severe injury, but did not have clear impact on survival

58 What is Still to Come? Lots of statistics! Migration rate etc. What variables contribute to mortality? Molecular Analyses Infectious agents Gene expression Fertilization study

59 Molecular Analyses DFO Pacific Biological Station (Nanaimo) Assays Samples Fluidigm Biomark real-time qpcr 96 x 96 (assays x samples) Infectious agent screening Gene expression Immune, wound healing, thermal response, etc.

60 Immune Biomarker Expression - Cell-mediated immunity (MHC1, MHC2) - Complement system (C7, CD83) - Inflammation (IRF, IL1B) - Wound Healing (MMP13, MMP25) Immune response downregulated over time

61 Fertilization Experiment Intergenerational impacts from gillnet injury? Egg size Energy density Survival Cortisol Transfer Offspring performance

62 Outline Fraser River sockeye management Research application and methods 2017 summer sockeye project 2018 late Shuswap sockeye project Summary

63 Summary High temperature results in high mortality Gillnet entanglement causes injury, fungus development, and elevated mortality Impact on females is most severe

64 Possible Applications Manage fishery openings based on river temperature Enhance estimation, management adjustments Manage fishery gear choice and deployment

65 Thank you for your attention! Any questions?