The Salmon Decline Continued

The Salmon Population

Factors Causing Salmon Decline:

Salmon Decline Matrix

Problem Dams Logging Changing
Climate Agriculture Pop. Growth Over Fishing Other
Salmon Migration Barriers Big Time no no no no no no

Barriers to Reaching Spawing Grounds Yes no Yes no no Yes! no

Reduced Number of Young Salmon reaching sea yes yes no no no no bird
predation

Pesticide Exposure no Yes no Yes no no no

Industrial Pollutants Exposure no no no no Yes no no

Loss of Streamside Vegetation and Functions no Yes no Yes Yes no no

Increased Sediment Load no Yes Yes Yes Yes no no

Natural Habitat Destruction yes yes no yes yes no no

Reduced Fresh Water Flow in Rivers and Streams yes no no yes yes no no

Abnormal water temperatures yes no yes yes no no no

Reduced upwelling and nutrient/food supply no no yes no no no competition with hatchery fish

Estuary Degradation no Yes no no Yes no no

Loss of cool deep pools in streams no Yes no no no no no

Problem	Dams	Logging	Changing Climate	Agriculture	Pop. Growth	Over Fishing	Other
Salmon Migration Barriers	Big Time	no	no	no	no	no	no
Barriers to Reaching Spawing Grounds	Yes	no	Yes	no	no	Yes!	no
Reduced Number of Young Salmon reaching sea	yes	yes	no	no	no	no	bird predation
Pesticide Exposure	no	Yes	no	Yes	no	no	no
Industrial Pollutants Exposure	no	no	no	no	Yes	no	no
Loss of Streamside Vegetation and Functions	no	Yes	no	Yes	Yes	no	no
Increased Sediment Load	no	Yes	Yes	Yes	Yes	no	no
Natural Habitat Destruction	yes	yes	no	yes	yes	no	no
Reduced Fresh Water Flow in Rivers and Streams	yes	no	no	yes	yes	no	no
Abnormal water temperatures	yes	no	yes	yes	no	no	no
Reduced upwelling and nutrient/food supply	no	no	yes	no	no	no	competition with hatchery fish
Estuary Degradation	no	Yes	no	no	Yes	no	no
Loss of cool deep pools in streams	no	Yes	no	no	no	no	no

Qualitative Scorecard:

Dams: 6 strikes
Logging: 7 strikes
Climate Change: 4 strikes
Agriculture: 6 strikes
Overpopulation: 6 strikes
Overfishing: 1 (but its potentially the most important factor)
Other: 2

Abstract of a Recent Technical Paper

Evidence of a Nutrient Deficit in the Freshwater Systems of the Pacific Northwest. A comparison of historic and current levels of salmon abundance was used to determine the current deficit of marine-derived nutrients for Pacific Northwest streams. This nutrient deficit may be one indication of ecosystem failure that has contributed to the downward spiral of salmonid abundance, further diminishign the possibility of salmon population recovery to self-sustaining levels.

This is the raw salmon count data at Boneville Dam that we will inspect more closely below. Evidence of quasi-cylical behavior is apparent. Generating count Data (last year and this year are high!)

Some relevant WWW resources:

White Men Luv Fish

Pacific Northwest Index

Canadian Harvest Increases

Some Salmon Links

The above documents and data strongly suggest that a significant reason for Columbia river salmon decline is due to increased harvests in Alaska and Canada.

This is likely a reflection of where the Salmon are and this is strongly coupled to decadel climate changes in the Alaska-BC-PNW region.

This implies, that at any particular point in this region, over timescales of 50 years, salmon counts/catches will be cyclical in nature.

World Salmon Harvest

What about the viability of Dam Breaching?

the poll on tuesday showed that most believed this would *not* be effective. However, many thought it would or didn't know.

Pros and Cons of Dam Breaching:

Arguments For:

restore Salmon runs
restore river to its more natural state
create short term jobs (sledgehammer crew).

Arguments Against:

Loss of Power
Loss of flood control
Loss of Irrigation
Loss of River Navigation
Increased Turbidity
Toxic Waste movement down the river

How we can gather objective data on each of the items in the list.?

First we noticed that the listed items under Aguments against are quite obvious and really don't require justification. All of these things would happen, it just matters to which degree they would happen and this is very difficult to model.

So let's concentrate on the other items in the Arguments For column.

The principle hypothesis here is whether or not dams have caused a "catastrophic" loss of population.

We can use salmon count data as a means of establishing a baseline. We can then convolve that data with the following simple model:


X ----------|-------------|--------|------|--------|----|---|--|->  X'

            1             2        3      4        5    6   7  8

Suppose we have a system where X salmon enter and have to pass 8 dams to reach X'.

The issues are:

How many fish are eliminated by the first dam

Corps of Engineer Estimates
how many are eliminated by success dams?
does fish survival probability depend on dam size? distance from the mouth of the columbia river (assumes salmon get tired and find fish ladders more difficult to negogiate); salmon learning curve (assumes that salmon learn to look for fish ladders along the way thus reducing the mortality rate).

These hypothesis can be tested to some extent by the actual salmon count data which exists at each dam. That data is readily available .

But we aren't doing an indepth analysis here. Let's keep it simple.

Under the model where all dams are equal then we should see something like this in the data.

X₁ < X₂ < X₃ < X₄ < X₅ < ...

While there are complicating factors, this basic pattern should be defined the data on upstream salmon counts. You will be testing that in your next homework assignment.

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The Salmon Population

This is the raw salmon count data at Boneville Dam that we will inspect more closely below. Evidence of quasi-cylical behavior is apparent. Generating count Data (last year and this year are high!)

Arguments For: restore Salmon runs restore river to its more natural state create short term jobs (sledgehammer crew).

Arguments Against: Loss of Power Loss of flood control Loss of Irrigation Loss of River Navigation Increased Turbidity Toxic Waste movement down the river

Arguments For:

restore Salmon runs
restore river to its more natural state
create short term jobs (sledgehammer crew).

Arguments Against:

Loss of Power
Loss of flood control
Loss of Irrigation
Loss of River Navigation
Increased Turbidity
Toxic Waste movement down the river