Salmon (kill me)

Question 1

What are sea-run fish?

Answer 1

Fish that migrate from fresh water (home) to the ocean

Question 2

What are diadormous fish?

Answer 2

migrate between salt and fresh water
- 1% of world’s fish species
- must change physiology due to water chemistry changes

Question 3

Anadormous fish live their adult life in _____ water and migrate to _______ to spawn & hatch

Answer 3

salt to rivers & lakes

Question 4

What fish are anadromous?

Answer 4

salmon, herring, striped bass, etc.

Question 5

What are the three stages of a salmon life cycle?

Answer 5

1. River Cycle
   - spawn
   - eggs buried in redds (nests in coarse gravel)
   - after 1 yr the eggs hatch!
   - stay here for a total of two years
2. Estuary Cycle (brackish water)
3. Ocean Cycle
   - migrate here to mature
   - stay here for two years before returning to home rivers to spawn again

Question 6

The four Hs

Answer 6

1. Harvest
   - commercial fishing (typically overfishing is a huge issue that leads to salmon decline)
2. Habitat
   - accès to clean, high quality habitat without having to swim through dams
3. Hatcheries
   - solution to degradation caused by dams
   - limited success
4. Hydropower
   - problem for fish who are working to swim up stream

Question 7

What do salmon need?

Answer 7

A) cool, unpolluted water

B) Gravel bedded rivers to lay eggs

C) Hydrographs in sync with life cycle
- Spring flooding to carry juveniles downstream, yet not disrupting spawning beds

D) Woody debris and overhanging tree
- Shade
- Safety from predators
- Create side channels (where juveniles can hide during floods)

Question 8

Hatcheries were designed to…

Answer 8

replace stocks of salmon
- adult salmon comes up to its home river to spawn and instead of laying eggs in the gravel beds, they are captured and the eggs are incubated in a hatchery instead

Question 9

What are the pros of hatcheries?

Answer 9

• unlike the in the wild, a majority of salmon eggs are hatched (they are protected)
• hatchery fish are stronger and bigger due to being consistently fed
• Hatchery salmon are less genetically diverse

Question 10

When do hatcheries yield returning adults?

Answer 10

• when good habitat and good water quality are available hatcheries can be used to replenish depleted stocks
• when habitats are lost due to dams

Question 11

What are farmed salmon?

Answer 11

fish that spend their whole life in aquaculture facilities

Question 12

What are wild-caught salmons?

Answer 12

caught in wild, you don’t know whether if they are hatchery fish or from the river themselves

Question 13

Pacific salmon include which breed?

Answer 13

Coho, Chinook, Sockeye, and Pink

Question 14

> 60% of world’s commercial salmon comes from ________

Answer 14

aquaculture

Question 15

Why did salmon evolve to spend adult life in the oceans? (Why are they anadromous)

Answer 15

• oceans have more food than coldwater rivers

Question 16

Hydropower and dams

Answer 16

Problem #1: Barrier to migration upstream

Solution:
- Fish ladders
- Fish elevators
- Dam removal

Problem #2: Barrier to migration of juveniles swimming out to sea

Solution:
- Ladders and elevators do not work
- Run-of-the-river dams <25 ft tall, so fish can swim over
- Dam removal is also always an option

Problem #3: Juveniles diverted to irrigation canals and ditches

Solution: screens over inlets

Problem #4: Mortality in power turbines

Solution: screens

Problem #5: Changed flow, migration slowed by reservoirs & more juveniles die by predation before reaching ocean

Solution:
- trap & truck
- spill water from reservoirs during migration

Question 17

How do we create suitable living areas?

Answer 17

Study your answer on the problem set

Question 18

How do forest ecosystems help salmon?

A. All of these answers
B. Riparian trees provide shade, cooling summer water temperatures
C. Riparian trees fall in the river, providing cover for fish
D. Wood in streams leads to increased depth ad velocity variability in channels

Answer 18

All of the above

Question 19

How do salmon fertilize forest ecosystems?

Answer 19

carcasses provide marine-derived nutrients

Question 20

What river bed sediment grain size do most salmon species need for spawning habitat?

Answer 20

gravel

Question 21

Your supermarket is selling wild-caught Chinook salmon from Alaska. Where did it hatch?

A: a hatchery or a riverbed
B: a riverbed
C: a hatchery
D: a fish farm

Answer 21

A: a hatchery or a riverbed