Fish and Forestry - Final Flashcards
How does sediment in streams effect fish?
Sediment that gets suspended in streams causes a multitude of issues for fish and all other animals in the affected waters. The issues include:
- causes lack of visibility
- inhibits growth of algae by smothering them
- sediment can be deposited over and form a blanket over possible rearing areas (suffocating fish eggs)
- Can suffocate fish by entombing their gills in sediment
- Can inhibit aquatic growth and lower oxygen content in water
Why are BC forests so biologically successful?
One major factor is the addition of nutrients to forests by fish that use riparian zones. The broken down nutrients of the fish are fixed by mycorrhizal networks and bacterial organisms that give them up to trees and vegetation in exchange for sugars. These nitrogen rich nutrients are a key factor in the speed and extent of tree growth.
What are two fish species that spend their entire lives in fresh water?
Trout
Char
How does a riparian area prevent pollution of streams?
The roots of trees in the riparian stabilize the banks and as polluted groundwater percolates through the saturated soils, any fertilizers or sediment in filtered out by the soil so that the subterranean water is clean when it enters.
What kind of areas do fish need for spawning?
Ideal spawning areas are where water flows steadily over gravel banks
Where do juvenile fish go to overwinter?
How do these areas stay thawed?
Off channel areas are used by many species and the waters stay thawed due to the constant inflow of groundwater.
Why are amphibians so important in our ecosystems?
What amphibians are in trouble because of wetland destruction in BC?
Amount to 4x the biomass of fish in the Pacific NW and are a major source of food. (The fact that tadpoles convert vegetation to animal tissues makes them a very valuable organism in the food chain)
Pacific Giant Salamander
Oregon spotted frog
Tailed Frog
How much sedimentation from logging is from roads and bridges?
around 80%, making road construction a very important step in harvest planning.
How can we reduce our impact on streams when doing forestry activity?
- Construct roads and Bridges to avoid sensitive areas
- build adequate culverts and ditches
- when deactivating roads and culverts we should always ensure that original slope and stream conditions are achieved.
- clean unstable debris out of streams
- Use a sediment trapping cloth to filter sediment out of any water that is likely to be contaminated during activities.
- Leave stable debris as is in streams
Why do some salmon use streams at different times and only during certain periods?
Requirements for: -substrate -cover -Temperature -Water velocity -water level All differ between species
What is the term for fish that go out to sea for a portion of their lives?
Anadromous
What are newly hatched fish called? Briefly describe
Alluvin
These hatchlings are still attached to their egg sacks and pretty much just wriggle around in tiny interstitial spaces in the stream bed for two weeks getting nourished by their egg sack before shedding the sack and becoming fry.
Why must we take extreme caution when decommissioning ditches?
In many cases fry have been known to use ditches (probably mistaking them for offshore channels) in this case we must let the little buggers do their thing until its done.
What do fry feed on?
Mostly larval and mature insects as well as some crustaceans
When do fish form par marks? what are they for?
Par marks are dark bands that form on many species of salmon fry.
They serve as camouflage and fade as the fish matures.
