California Fish and Wildlife Technician
Certification Exam. These cover fish hatchery
operations, wildlife management, habitat
conservation, laws, safety, and field techniques.
Section 1: Fish Biology & Hatchery Operations (Questions 1–30)
1. Which method is most commonly used to spawn trout in a CDFW hatchery?
- A) Net seining
- B) Electrofishing
- C) Stripping eggs and milt
- D) Natural spawning in raceways
- Correct Answer: C
- Explanation: Stripping manually collects eggs and milt, allowing controlled fertilization, high
survival rates, and genetic management. It is the standard method in CDFW hatcheries.
2. What is an anadromous fish?
- A) Lives entirely in freshwater
- B) Migrates from sea to freshwater to spawn
- C) Lives only in the ocean
- D) Transitions between two freshwater rivers
- Correct Answer: B
- Explanation: "Anadromous" refers to fish like salmon and steelhead that mature in saltwater
but migrate to freshwater to spawn.
3. What is a "redd"?
- A) A type of fishing net
- B) A salmonid nest in gravel
- C) A fish trap
- D) A measuring tool
- Correct Answer: B
- Explanation: A redd is a gravel depression dug by female salmonids where eggs are deposited
and fertilized.
4. Which of the following is a cold-water fish species?
- A) Rainbow trout
- B) Bluegill
- C) Largemouth bass
- D) Channel catfish
,- Correct Answer: A
- Explanation: Rainbow trout require cold, oxygen-rich water below 68°F. Bluegill, bass, and
catfish are warm-water species.
5. What is the ideal water temperature range for rearing Chinook salmon?
- A) 0–4°C (32–39°F)
- B) 8–12°C (46–54°F)
- C) 18–22°C (64–72°F)
- D) 25–30°C (77–86°F)
- Correct Answer: B
- Explanation: Chinook salmon thrive at 8–12°C. Higher temperatures reduce dissolved oxygen
and increase disease risk.
6. What is the purpose of a mechanical fish egg incubator (e.g., Heath tray)?
- A) To feed fry automatically
- B) To provide controlled water flow and protection for developing eggs
- C) To sort fish by size
- D) To aerate adult holding tanks
- Correct Answer: B
- Explanation: Heath trays allow water to flow over eggs, removing waste, preventing fungal
growth, and maintaining oxygen levels.
7. What is the "swim-up" stage in hatchery production?
- A) When eggs are first fertilized
- B) When fry absorb their yolk sac and begin active feeding
- C) When fingerlings are transferred to raceways
- D) When broodstock are spawned
- Correct Answer: B
- Explanation: At swim-up, fry have absorbed their yolk sac and rise to the water surface to feed,
marking the start of exogenous feeding.
8. Which pathogen causes whirling disease in trout?
- A) Aeromonas salmonicida
- B) Myxobolus cerebralis
- C) Ichthyophthirius multifiliis
- D) Renibacterium salmoninarum
- Correct Answer: B
- Explanation: Myxobolus cerebralis is a parasite that infects cartilage, causing skeletal
deformities and whirling behavior.
9. How often should dissolved oxygen (DO) be checked in raceways?
- A) Once per week
- B) Daily or twice daily
- C) Once per month
,- D) Only after fish die
- Correct Answer: B
- Explanation: DO levels below 5 mg/L cause stress and mortality. Daily monitoring is essential
for fish health.
10. What is the typical protein percentage in feed for juvenile Chinook salmon?
- A) 20–25%
- B) 30–35%
- C) 40–50%
- D) 55–65%
- Correct Answer: C
- Explanation: Juvenile salmon require high protein (40–50%) for rapid growth, muscle
development, and smoltification.
11. What is a "flow-through" hatchery system?
- A) Water is recirculated after treatment
- B) Water passes through raceways once before discharge
- C) Fish are raised in closed tanks with no water exchange
- D) Water is heated and cooled cyclically
- Correct Answer: B
- Explanation: Flow-through systems use a continuous supply of fresh water, which is
discharged after one pass. Common in CDFW hatcheries.
12. What does "fin clipping" allow hatchery staff to track?
- A) Fish weight
- B) Hatchery-origin vs. wild fish
- C) Water temperature
- D) Feed conversion ratio
- Correct Answer: B
- Explanation: Different fin clips (e.g., adipose fin removal) identify hatchery fish in population
surveys and evaluate hatchery contribution.
13. What is the primary cause of gas bubble disease in hatcheries?
- A) Low oxygen
- B) High ammonia
- C) Supersaturated total dissolved gases (TDG)
- D) High pH
- Correct Answer: C
- Explanation: TDG supersaturation (often from water falling over dams) causes gas bubbles in
fish tissues, leading to embolism and death.
14. Which salmonid species is native to California and listed as threatened?
- A) Atlantic salmon
- B) Central Valley spring-run Chinook salmon
, - C) Lake trout
- D) Brown trout
- Correct Answer: B
- Explanation: Central Valley spring-run Chinook salmon are listed as threatened under both
state and federal Endangered Species Acts.
15. What is the purpose of a "Vibert box"?
- A) Holding adult fish
- B) Incubating fish eggs in remote stream gravels
- C) Measuring water flow
- D) Anesthetizing fish
- Correct Answer: B
- Explanation: Vibert boxes are placed in stream gravels to protect and incubate eggs in remote
enhancement projects.
16. Which anesthetic is approved for sedating fish during handling or tagging?
- A) Clove oil
- B) MS-222 (tricaine methanesulfonate)
- C) Ethanol
- D) Formalin
- Correct Answer: B
- Explanation: MS-222 is FDA-approved for fish sedation. It reduces stress and injury during
handling, tagging, or transport.
17. What is a "piscicide" used for?
- A) Stimulating spawning
- B) Removing unwanted fish species
- C) Increasing growth rate
- D) Preventing bacterial disease
- Correct Answer: B
- Explanation: Piscicides like rotenone and antimycin are used to eradicate invasive or
undesirable fish from waterbodies.
18. What does "PIT tag" stand for?
- A) Passive Internal Tracker
- B) Passive Integrated Transponder
- C) Programmable Identification Tag
- D) Permanent Indwelling Tag
- Correct Answer: B
- Explanation: A PIT tag is a small electronic tag injected into fish for individual identification and
tracking.
19. What is the main advantage of recirculating aquaculture systems (RAS)?
- A) Lower construction cost
Certification Exam. These cover fish hatchery
operations, wildlife management, habitat
conservation, laws, safety, and field techniques.
Section 1: Fish Biology & Hatchery Operations (Questions 1–30)
1. Which method is most commonly used to spawn trout in a CDFW hatchery?
- A) Net seining
- B) Electrofishing
- C) Stripping eggs and milt
- D) Natural spawning in raceways
- Correct Answer: C
- Explanation: Stripping manually collects eggs and milt, allowing controlled fertilization, high
survival rates, and genetic management. It is the standard method in CDFW hatcheries.
2. What is an anadromous fish?
- A) Lives entirely in freshwater
- B) Migrates from sea to freshwater to spawn
- C) Lives only in the ocean
- D) Transitions between two freshwater rivers
- Correct Answer: B
- Explanation: "Anadromous" refers to fish like salmon and steelhead that mature in saltwater
but migrate to freshwater to spawn.
3. What is a "redd"?
- A) A type of fishing net
- B) A salmonid nest in gravel
- C) A fish trap
- D) A measuring tool
- Correct Answer: B
- Explanation: A redd is a gravel depression dug by female salmonids where eggs are deposited
and fertilized.
4. Which of the following is a cold-water fish species?
- A) Rainbow trout
- B) Bluegill
- C) Largemouth bass
- D) Channel catfish
,- Correct Answer: A
- Explanation: Rainbow trout require cold, oxygen-rich water below 68°F. Bluegill, bass, and
catfish are warm-water species.
5. What is the ideal water temperature range for rearing Chinook salmon?
- A) 0–4°C (32–39°F)
- B) 8–12°C (46–54°F)
- C) 18–22°C (64–72°F)
- D) 25–30°C (77–86°F)
- Correct Answer: B
- Explanation: Chinook salmon thrive at 8–12°C. Higher temperatures reduce dissolved oxygen
and increase disease risk.
6. What is the purpose of a mechanical fish egg incubator (e.g., Heath tray)?
- A) To feed fry automatically
- B) To provide controlled water flow and protection for developing eggs
- C) To sort fish by size
- D) To aerate adult holding tanks
- Correct Answer: B
- Explanation: Heath trays allow water to flow over eggs, removing waste, preventing fungal
growth, and maintaining oxygen levels.
7. What is the "swim-up" stage in hatchery production?
- A) When eggs are first fertilized
- B) When fry absorb their yolk sac and begin active feeding
- C) When fingerlings are transferred to raceways
- D) When broodstock are spawned
- Correct Answer: B
- Explanation: At swim-up, fry have absorbed their yolk sac and rise to the water surface to feed,
marking the start of exogenous feeding.
8. Which pathogen causes whirling disease in trout?
- A) Aeromonas salmonicida
- B) Myxobolus cerebralis
- C) Ichthyophthirius multifiliis
- D) Renibacterium salmoninarum
- Correct Answer: B
- Explanation: Myxobolus cerebralis is a parasite that infects cartilage, causing skeletal
deformities and whirling behavior.
9. How often should dissolved oxygen (DO) be checked in raceways?
- A) Once per week
- B) Daily or twice daily
- C) Once per month
,- D) Only after fish die
- Correct Answer: B
- Explanation: DO levels below 5 mg/L cause stress and mortality. Daily monitoring is essential
for fish health.
10. What is the typical protein percentage in feed for juvenile Chinook salmon?
- A) 20–25%
- B) 30–35%
- C) 40–50%
- D) 55–65%
- Correct Answer: C
- Explanation: Juvenile salmon require high protein (40–50%) for rapid growth, muscle
development, and smoltification.
11. What is a "flow-through" hatchery system?
- A) Water is recirculated after treatment
- B) Water passes through raceways once before discharge
- C) Fish are raised in closed tanks with no water exchange
- D) Water is heated and cooled cyclically
- Correct Answer: B
- Explanation: Flow-through systems use a continuous supply of fresh water, which is
discharged after one pass. Common in CDFW hatcheries.
12. What does "fin clipping" allow hatchery staff to track?
- A) Fish weight
- B) Hatchery-origin vs. wild fish
- C) Water temperature
- D) Feed conversion ratio
- Correct Answer: B
- Explanation: Different fin clips (e.g., adipose fin removal) identify hatchery fish in population
surveys and evaluate hatchery contribution.
13. What is the primary cause of gas bubble disease in hatcheries?
- A) Low oxygen
- B) High ammonia
- C) Supersaturated total dissolved gases (TDG)
- D) High pH
- Correct Answer: C
- Explanation: TDG supersaturation (often from water falling over dams) causes gas bubbles in
fish tissues, leading to embolism and death.
14. Which salmonid species is native to California and listed as threatened?
- A) Atlantic salmon
- B) Central Valley spring-run Chinook salmon
, - C) Lake trout
- D) Brown trout
- Correct Answer: B
- Explanation: Central Valley spring-run Chinook salmon are listed as threatened under both
state and federal Endangered Species Acts.
15. What is the purpose of a "Vibert box"?
- A) Holding adult fish
- B) Incubating fish eggs in remote stream gravels
- C) Measuring water flow
- D) Anesthetizing fish
- Correct Answer: B
- Explanation: Vibert boxes are placed in stream gravels to protect and incubate eggs in remote
enhancement projects.
16. Which anesthetic is approved for sedating fish during handling or tagging?
- A) Clove oil
- B) MS-222 (tricaine methanesulfonate)
- C) Ethanol
- D) Formalin
- Correct Answer: B
- Explanation: MS-222 is FDA-approved for fish sedation. It reduces stress and injury during
handling, tagging, or transport.
17. What is a "piscicide" used for?
- A) Stimulating spawning
- B) Removing unwanted fish species
- C) Increasing growth rate
- D) Preventing bacterial disease
- Correct Answer: B
- Explanation: Piscicides like rotenone and antimycin are used to eradicate invasive or
undesirable fish from waterbodies.
18. What does "PIT tag" stand for?
- A) Passive Internal Tracker
- B) Passive Integrated Transponder
- C) Programmable Identification Tag
- D) Permanent Indwelling Tag
- Correct Answer: B
- Explanation: A PIT tag is a small electronic tag injected into fish for individual identification and
tracking.
19. What is the main advantage of recirculating aquaculture systems (RAS)?
- A) Lower construction cost
