Modeling physical environmental impacts on survival: the SHIRAZ model Ecosystem based management FISH 507

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

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

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

It is convenient to break the life history into stages Number stage+1 = Number stage * survival stage Survival depends on food, competitors, predators, and habitat

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

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

For MSY

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

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

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

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 …

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

Sharma coho carrying capacity

Snoqualamie Snohomish River basin SHIRAZ Model

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

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

Impacts of climate change from Battin et al 2007

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

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

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

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

EBM exercises No spatial resolution Only a single stock No hatcheries

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

Impact of supplementation from Sharma Cooper and Hilborn

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

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

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