Overview of herring related findings of NCEAS Portfolio Effects Working Group

Transcription

1 Overview of herring related findings of NCEAS Portfolio Effects Working Group Northwest Eric Ward, Rich Brenner September 8, 2017

2 Acknowledgments Thanks to S. Moffitt and J. Rice for help with data / synthesis

3 Background: other oil spill responses Deepwater Horizon (2010) in Gulf of Mexico Synthesized long term monitoring data from LDWF 3 gears, 12 species, data from 1968 present Monthly sampling, environmental covariates Lack of anomaly or state change following DWH event (Ward et al. in review)

4 BUT we see clear responses in lab settings Incardona et al. (2015) herring and pink salmon associated with EVOS Incardona (2014) Deepwater Horizon response Why are clear responses in the lab not mirrored in wild populations? U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 4

5 Lab vs Population Responses (Fodrie et al. 2014) Exposure Intrinsic factors Life history variation (overlapping generations) Spatial variation in timing Environmental variation Hurricanes, warm blob Human adjustments Management changes, fisheries closures, dispersants U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 5

6 Summary of group s work 1. Summarize long term trends in herring catches and fisheries 2. Evaluate patterns of changing growth rates 3. Identify single factors associated with productivity in herring, salmon populations 4. Why are there more male herring? 5. Meta-analysis comparing SEAK populations to PWS U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 6

7 Long history of exploitation in Alaska and PWS Catches (1000 kgs) Reduction Seine Bait Pound Gill Figure 3: Time series of catches, Catches after 1970 were converted from numbers to weight, with Reid (1971) and Funk & Sandone (1989, 1990) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 7

8 1970s: emerging fishery, new products Herring roe harvested for Japanese export Demand / prices peaked ~ $2,500 Average ex-vessel roe herring price paid in select roe herring purse seine fisheries, nominal dollars Price/ton $2,000 $1,500 $1,000 (Carlson 2005, CFEC) $500 $ Southeast Prince Wm. Sound Cook Inlet Kodiak Alaska Pen-Aleutian Is Bristol Bay U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 8

9 How have these changes affected fishers? Rise of the single permit holder (Anderson et al. 2017) People who specialize (hold 1 permit) tend to have greater variability in income than people with 2+ permits Despite closures, PWS herring permits continue to be bought / sold Like other fisheries in AK that have been closed / experienced restrictions, many individuals have stopped fishing (Beaudreau et al. in review) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 9

10 Identifying single drivers associated with salmon / herring productivity Modeled after Deriso et al. (2008), for herring and salmon in PWS Covariates organized by hypothesis Model selection used to evaluate relative data support of various covariates What this analysis isn t: exhaustive model selection to find single best model Comprehensive analysis of every potential driver U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 10

11 Hypotheses 1. Productivity most strongly affected by EVOS 2. Density dependence (SSB) 3. Environmental covariates (discharge, SST, etc) 4. Competition and / or predation with other species (including hatchery salmon) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 11

12 What we found Herring don t have strong effect of Ricker density dependence Copper River Chinook Coghill Lake sockeye log (R/S) log (R/S) Spawners Eshamy Lake sockeye Spawners Copper River sockeye log (R/S) log (R/S) log (R/S) Spawners PWS pink 2.0e e e e+07 Spawners log (age 3 recruits / SSB) e+05 6e+05 7e+05 8e+05 9e+05 Spawners PWS herring 2e+04 4e+04 6e+04 8e+04 1e+05 Spawning biomass (mt) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 12

13 But some negative effect of discharge High discharge = low recruitment (a) Total discharge m 3 s log (age 3 recruits / SSB) (b) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 13

14 Interestingly, discharge also record low / volatile in 1930s Total freshwater discharge m 3 s U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 14

15 More on discharge Where s it coming from? Approximately 50% glaciers (Beamer et al. 2016; Hill et al. 2015) What s it doing? Altering timing / quality of plankton bloom (= food for herring) Similar patterns seen in Europe U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 15

16 Why are there more male herring? More male herring in research vessels over time during spawning 0.6 Percent male Year U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 16

17 Lots of potential reasons Was it EVOS? Other change in population? Nutritional stress? Change in sampling? Other regions (Puget Sound) don t show much variation in sex ratios Implications for management, assessment models U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 17

18 No clear effect of EVOS Contrasted oiled versus un-oiled sampling sites in PWS to identify effects (or oiled:year interactions) No significant effect found explaining the trend U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 18

19 But large changes over time in sampling gears Cast and purse seines are dominant gear types 7500 Samples 5000 Gear Cast net Purse seine Year U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 19

20 Sex ratio trend driven by gear change Increased trend in males = Increased cast nets + Cast nets selecting more males Predicted proportion of males 0.55 Gear Cast net Purse seine Age U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 20

21 Implications for assessment models Cast / seine samples occur in different places May capture different portions of spawn Modeling changes: sex- and gear- specific selectivities Future research: could we include time-varying selectivity over duration of spawn U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 21

22 Summary Multiple factors responsible for herring not recovering Limitations of monitoring data Synthesis paper (Marshall et al.) Future work: comparisons across spatial locations Do SEAK populations share response to discharge? Questions? U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 22