Modeling Disease in Pacific SalmonEstablishing Watershed Models for Predicting Effects of Climate Change

Jerri BartholomewDepartment of Microbiology

Graduate students: Sarah Bjork (2008) Luciano Chiaramonte (2010) Adam Ray (2012)

9 March 2012

Myxospore Myxospore ActinosporeActinospore

Salmon Salmon

Polychaete Polychaete

Problem: Projected increasing temperatures for rivers where salmon populations are already threatened

MyxosporeMyxosporeActinosporeActinospore

Polychaete hostPolychaete host

Salmon hostSalmon host

Increased parasite replication

Altered timing of parasite release

Increased stress - causing reduced disease thresholds

Changes in population dynamics

Altered longevity of parasite stages

Ceratomyxa shasta life

cycle

Increasing temperature and altered ecosystem processes will have multiple effects on host-parasite dynamics

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These changes will have profound effects on the outcome of infections by a variety of pathogens

Outcomes

Changes in disease severity

Changes in seasonal

cycles

Changes in pathogen range

Layered on this is the altered effectiveness of management strategies as the amount of cold, fresh water becomes limited.

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Degree-day model of the parasite life cycle

Hydraulic model for the invertebrate host habitat (USFWS collaboration)

Basin Characterization Model for the Klamath River (USGS)

This study will link models to assess the interaction of disease and climate change effects on wild salmon

Epidemiological model

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Degree-day model of the parasite life cycle

Hydraulic model for the invertebrate host habitat (USFWS collaboration)

Basin Characterization Model for the Klamath River (USGS)

This study will link models to assess the interaction of disease and climate change effects on wild salmon

Epidemiological model

Outcome: Predict changes in disease severity and distribution under different climatic scenarios

The watersheds selected for this study have different characteristics and predictions for climate effects differ – C. shasta is present in both

Klamath River• Warmer water temperatures• Altered timing and magnitude of flow events• Increase in runoff and sedimentation

Willamette River• Changes may not be as dramatic or extreme as predicted for the Klamath

• larger discharge volume and the cooler profile • more of its basin is above 2500 m, buffering system from change

Outcomes directed toward management for healthy fisheries

Identification of critical habitats for protection

– “disease refugia”

A model that can be used to predict changes in disease severity and distribution of Ceratomyxa shasta

- other host-pathogen systems

Educational Tools: Produced in collaboration with Educational Solutions

Documentary video

Online high school curriculum

http://www.educationalsolutions.org/introduction.html

10 Questions?

In summary, linking these models will allow us predict how climate change will alter disease in salmon

Luciano Chiaramonte, MS thesis

USGS model

Hydraulic Model

Hydraulic Model

Basin Characterization

Model

Basin Characterization

Model

Degree Day

Model

Degree Day

Model

Epidemiological Model

Epidemiological Model

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Measured Runoff Baseflow Discharge

Ro & Disease Trends

Ro & Disease Trends

Climate ModelsClimate Models

Adam Ray, PhD thesis