Modeling physical environmental impacts on survival: the SHIRAZ model

1. Modeling physical environmental impacts on survival:the SHIRAZ model Ecosystem based managementFISH 507

2. SHIRAZ publications Scheuerell, M. D., Hilborn, R., Ruckelshaus, M. H., Bartz, K. K., Lagueux, K. M., Haas, A. D., and Rawson, K. 2006. The Shiraz model: a tool for incorporating anthropogenic effects and fish-habitat relationships in conservation planning. Can. J. Fish. Aquat. Sci. 63: 1596-1607. Battin, J., Wiley, M. W., Ruckelshaus, M. H., Palmer, R. N., Korb, E., Bartz, K. K., and Imaki, H. 2007. Projected impacts of climate change on salmon habitat restoration. Proceedings of the National Academy of Sciences of the United States of America. 104: 6720-6725. Honea, J. M., Jorgensen, J. C., McClure, M. M., Cooney, T. D., Engie, K., Holzer, D., and Hilborn, R. 2009. Evaluating habitat effects on population status: influence of habitat restoration on spring-run Chinook salmon. Freshwater Biology. doi:10.1111/j.1365-2427.2009.02208.x.

3. Motivation for habitat modelling • One element of fisheries management is habitat protection and restoration • In Pacific Northwest hundreds of millions of dollars are being spent on these items • How do we evalute the priority or cost benefit ratio of the different kinds of activities

4. Fish live life one day at a time • The probability of survival depends upon feeding, and surviving • The key factors are protection from predators, availability of food, influence of competitors, the right habitat and physical conditions

5. It is convenient to break the life history into stages Numberstage+1= Numberstage * survivalstage Survival depends on food, competitors, predators, and habitat

6. Moussalli generalization 1986 • Assume a Beverton-Holt form for each life history stage • p is productivity • c is capacity • Habitat, competitors, food, predators affect the productivity and capacity

7. Over a series of life history stages The productivity and capacity over the entire life history are simple functions of the individual p’s and c’s at the stages Note the capital P in denominator The series of life history stages is a Beverton-Holt model

8. For MSY

9. Life history and habitat • The Moussalli form provides the basis for life history models SHIRAZ and EDT • Both of these are now used to evaluate impacts of habitat change on Pacific salmon

10. Basic concepts of SHIRAZ • Life history stages • Divide watersheds into segments • In each segment describe a range of habitat characteristics • Functional relationships between habitat characteristics and productivity and capacity at each stage • Stocks, that have different life history stages, spring vs fall chinook, hatchery vs wild

11. SHIRAZ Concept Landscape processes Land use Habitat effects Hatchery effects Life-cycle model Harvest effects Hydropower effects SHIRAZ

12. Habitat characteristics • Square meters of spawning gravel • Area of pools and ponds for rearing • Percent fine sediments in spawning gravel • Maximum flow of stream during incubation • Maximum flow of stream during rearing • Minimum flow of stream …

13. Functional relationships • For each life history stage in each area there are two parameters, productivity and capacity • Each of these is defined as a function of habitat characteristics

14. Sharma coho carrying capacity

15. Snoqualamie Snohomish River basin SHIRAZ Model

21. Major habitat changes • Dyking and farming lower watershed – loss of rearing area • Road construction and logging in upper watershed • Increased sediment in spawning areas • Increased flow variability

22. Uses of SHIRAZ • Evaluate rebuilding plans for Endangered Species Act mandates • Evaluate impacts of alternative expected habitat changes • Identify cost-effectiveness of alternative habitat improvements • Evaluate impacts of hatcheries • Evaluate impacts of climate change

25. Impacts of climate changefrom Battin et al 2007

26. Escapement goals • There are generally three approaches to setting escapement goals • Historical averages • Spawner-recruit analysis • Habitat based assessments • Mixing different types of data • Considering nutrient impacts

27. Habitat based approaches • Limiting factors evaluation • Spawning area (many species) • Lake rearing capacity (sockeye) • Freshwater rearing (coho)

28. Essential fish habitat • Required to be protected under Magnusson Stevens act • SHIRAZ provides a quantitative framework for evaluating the importance of different habitat elements • In a SHIRAZ model some habitat will be more limiting than others • We can calculate the derivative of the population abundance with respect to each habitat

29. Models of habitat impacts for marine fishes • In general we don’t understand the relationship between ocean physical habitat and marine fish survival • OR there is nothing we can do about it • As a result almost all marine fish ecosystem models are trophic

30. EBM exercises • No spatial resolution • Only a single stock • No hatcheries

33. Hatchery impacts • Hatchery fish can potentially compete with wild salmon • Hatchery fish may also effect wild fish through genetic impacts • Hatchery fish may potentially supplement and help rebuild wild fish

34. Impact of supplementationfrom Sharma Cooper and Hilborn

35. Optimal harvesting if we know pre-spawning mortality and ocean conditions

36. The best escapement :giving up one fish in the catch produces one additional fish in subsequent recruitment Best Escapement

37. What to do with 50% reduction in ocean survival or 50% prespawning mortality