Lecture 8 - Biostandards

Question 1

What is the hierarchical stream restoration strategy? (10)

Answer 1

1. Complete hill slope and riparian stabilization first
2. Examine the need for off-channel restoration (refuge during construction)
3. Examine all feasible restorative and rehabilitative options
4. Prioritize sub-watersheds that are less highly impacted first
5. Emulate nature by use of natural templates within undisturbed reaches of streams
6. Assess and quantify if the resource (stream channel and fish habitat) is impaired and to what extent
7. Estimate the time to recovery without management (passive restoration)
8. If too long, assess if restoration is feasible (cost, logistics etc.)
9. Be sure that the restoration plan you are considering will be resilient to climate change
10. Do all feasible restoration, rehabilitation, or mitigation options (first at the impact site or if necessary in an adjacent watershed)

Question 2

Why should we use biostandards? (7)

Answer 2

1. Permits quantitative assessment of expected restoration efforts
2. Allows estimation of costs vs benefits
3. Can be used to prioritize project implementation
4. May be required for legal purposes
5. Facilitates effectiveness monitoring of projects
6. Encouraged learning from experience
7. Provided personal protection from the bean counters and naysayers

Question 3

Why focus on salmonids? (5)

Answer 3

Salmon require high quality water and intact habitat

Habitat restored to “salmon quality” is usually adequate for most species (except in some specific cases)

Salmonids are a key component of BC, Canadian, and Pacific Northwest cultural heritage

Salmonids are critical to social and spiritual well-being of many of BC’s First Nations communities

Keystone species

Question 4

What are the first 2 questions you ask before starting any stream restoration project?

Answer 4

What species are involved?

Do they have an anadromous or resident life history?

Question 5

Why is life history important? (5)

Answer 5

Some anadromous salmonids have an extended freshwater period (eg. Steelhead)

Whereas some fry leave for the ocean shortly after hatching (eg. Pink Salmon)

Some anadromous species even have different life history characteristics within the same species (eg. Chinook)

Salmonids particularly have a wide range of life history characteristics

This influences the restoration options that will be effective

Question 6

What are the 7 main categories important for salmonids rearing habitat, and which 4 are the most important?

Answer 6

Depth
Velocity
Substrate
Cover

Temperature
Nutrients
Dissolved Oxygen

Question 7

What is the scale for classifying the diameters of sediments?

Answer 7

Wentworth Scale

Question 8

What fish characteristic is very important in dictating rearing habitat and how does it relate to the 3 most important rearing habitat variables?

Answer 8

Fish body size, as larger fish require deeper (depth) and faster (velocity) water with larger cobbles (substrate)

Question 9

How do salmon select foraging areas? (3)

Answer 9

Based on the trade-off between obtaining a sufficient supply of invertebrate drift and the energy costs of maintaining their position in the river current

Because energy increases as a function of body weight, larger fish expend less energy swimming in higher currents

Microhabitat and fish size must be taken into account in restoration

Question 10

Why is cover important for rearing habitat? (3)

Answer 10

Salmon require cover, especially if the water is shallow

Amount and type of cover varies with species and life history stage

Juveniles require cover to avoid predation while adults use cover to avoid larger predators and to prey in smaller organisms

Question 11

Why is temperature an important aspect of rearing habitat? (4)

Answer 11

Salmonids are cold-blooded animals so their body is controlled by the environment in which they live

Salmonids have an optimal range as well as lower and upper lethal limits for various activities

High temperatures can increase metabolic rate which increases oxygen uptake and food demand

It can also increase incidence of disease and invasive species like largemouth bass

Question 12

What happens when canopy cover is removed? (5)

Answer 12

Increased light and temperature increases primary production because of higher algae production and increased decomposition of OM

This may lead to an increase in invertebrate production or a change in species composition

Which may lead to an increase of drift (fish food) within the stream ecosystem

This increased food supply will increase fish growth and production up to a certain optimum temperature

The metabolic rate of fish will also increase, however, which can cancel the beneficial effect on increased food supply when exceeding optimum temperatures

Question 13

What is the optimum and lethal temperatures for sockeye salmon? (2)

Answer 13

Optimum = 12-14 degrees C

Upper lethal = 25 degrees C

Question 14

What benefit might the hypoheic zone have on temperature?

Answer 14

Although it is the same temperature as the flow in the stream, there is a potential buffering effect that might be a temporary refuge for overheated salmonids

Question 15

When is dissolved oxygen at maximum concentration and what factors determine the saturation concentration? (2)

Answer 15

Saturation concentration of oxygen is determined by water temperature, salinity, and atmospheric pressure (elevation)

The max amount of DO that water can hold is 14.7 parts per million (or mg/L)

Question 16

What is an adequate amount of dissolved oxygen for salmonids? (2)

Answer 16

Over 5 ppm - anything below 6-7 ppm creates a decrease in performance

Anything below 3 does not support fish

Question 17

What’s the relationship between fish size and territory? (2)

Answer 17

Territory size limits the density and production of stream dwelling salmonids because it is dependent on food abundance - if food is high, fish would require smaller areas to sustain themselves

It is also dependent on fish size - thus fish size can be used to predict the space requirements and hence maximum densities or salmonids in streams (bigger fish need bigger territories)

Question 18

Why is off-channel and overwintering habitat important? (2)

Answer 18

Salmonids often seek over-wintering areas until water temperatures increase sufficiently to make active feeding a net positive energy gain

Depending on the species, salmonids often make short migrations into over-wintering habitat (coho) or stay in the stream and hide under large substrate (steelhead)

Question 19

What are the 5 most important aspects of spawning habitat?

Answer 19

Depth
Velocity
Substrate
Temperature 
Dissolved oxygen

Question 20

Where do salmonids often build their redds? (2)

Answer 20

At the top crest of a riffle to increase oxygenated water

Some build their reds in areas of groundwater seepage

Question 21

Why does fry emergency occur in the spring?

Answer 21

Salmonids have evolved to take advantage of increased lake and stream productivity during the summer months

Question 22

What is the general water velocity and water depth good for salmonids spawning? (2)

Answer 22

Average velocity = 49 cm/sec

Average water depth = 35 cm

Question 23

What is an important characteristic of fish that affects their spawning habitat? (2)

Answer 23

Their size - the bigger the fish, the deeper and faster the stream and larger the substrate needed for spawning

Larger fish also generally build larger redds and defend larger territories (4X the size of the redd)

Question 24

Why is marine survival of salmonids decreasing? (3)

Answer 24

PDO and El Niño causing a reduction in nutrient upwelling causing less production and less zooplankton that can be eaten by juvenile salmonids

Net pen diseases are also an issue = open net pen aquaculture and sea lice

Predation = can especially be a problem during El Niño and warm PDO years when mackerel appear off the BC coast

Question 25

When does most salmonid production bottleneck? (3)

Answer 25

During winter (high flows, lack of food, lack of overwintering habitat)

During summer (low flows, lack of habitat, high temperatures, predation)

You must make sure your restoration activities address the bottlenecks for a population that suits the salmon life history or else you will be wasting time and money