California Fish and Wildlife Technician
Certification Exam 2026 – 300 Questions with
Answers & Rationales
Section 1: Fish Hatchery Operations & Fisheries Management (Questions 1–50)
1. When backfilling stream habitat structures such as log or boulder placements during
restoration work, what is the correct technique to ensure long-term stability?
A) Leave large rocks loose to allow natural shifting
B) Compact soil in layers around and under the structures
C) Use clay exclusively to seal all gaps completely
D) Remove all riparian vegetation before backfilling
✅ Correct Answer: B
Rationale: Layered compaction around in-stream structures stabilizes them against high
flows and significantly reduces erosion potential over time .
2. A Fish and Wildlife Technician observes a large fish kill in a freshwater lake during
mid-summer. The water has a greenish scum on the surface. What is the most likely
primary cause?
A) Overpopulation of predatory birds
B) Toxic algal bloom (cyanobacteria) producing hypoxia
C) Introduction of a non-native predatory fish species
D) Sudden drop in water temperature
✅ Correct Answer: B
Rationale: Greenish scum on the water surface during summer indicates a cyanobacterial
(blue-green algae) bloom. When such blooms die, their decomposition consumes
dissolved oxygen, causing hypoxia and fish kills .
3. What is the primary purpose of a fish raceway in a hatchery setting?
A) To separate different species for breeding isolation
B) To aerate water before it enters the main facility
,C) To confine and rear fish in a controlled flowing-water environment
D) To filter debris and sediment from incoming water
✅ Correct Answer: C
Rationale: Raceways are long, narrow channels that provide continuous water flow, which
is essential for oxygenating and carrying waste away from high-density fish populations.
This controlled environment maximizes rearing efficiency .
4. You are electrofishing for a population survey in a stream. What is the most critical
safety concern you must constantly monitor?
A) Risk of slipping on wet algae-covered rocks
B) Electrical current passing through water is dangerous to humans
C) Losing expensive sampling equipment in deep pools
D) Disturbing natural sediment and reducing water clarity
✅ Correct Answer: B
Rationale: Electrofishing uses electrical current to temporarily stun fish for capture and
study; the same current is dangerous or fatal to humans if safety protocols like insulated
waders are not followed .
5. In hatchery operations, which bacterial disease is most common in trout and caused by
Aeromonas salmonicida?
A) Chilodonella
B) Furunculosis
C) Ichthyophthirius
D) Anchor worm infestation
✅ Correct Answer: B
Rationale: Furunculosis is a prevalent bacterial disease in salmonid hatcheries caused by
Aeromonas salmonicida. It causes lesions and internal organ damage, requiring prompt
water quality and treatment management .
6. A fish ladder is installed at a dam primarily to achieve what objective?
A) Divert water for agricultural irrigation systems
B) Filter debris and sediment from the water flow
,C) Enable fish to bypass barriers and migrate upstream
D) Measure flow velocity for hydroelectric generation
✅ Correct Answer: C
Rationale: Fish ladders allow migratory fish such as salmon and steelhead to swim
upstream past obstructions such as dams, reaching critical spawning grounds that would
otherwise be inaccessible .
7. The life stage immediately after a fish hatches from its egg is called:
A) Fry
B) Juvenile
C) Alevin
D) Fingerling
✅ Correct Answer: C
Rationale: The alevin stage begins immediately after hatching. Alevins still have their yolk
sac attached, which provides nutrition until they absorb it and become fry. Fry then
develop into fingerlings and then juveniles .
8. When transporting live fish between facilities, what is the minimum dissolved oxygen
level that must be maintained in transport water?
A) 2 mg/L
B) 5 mg/L
C) 8 mg/L
D) 10 mg/L
✅ Correct Answer: B
*Rationale: Maintaining dissolved oxygen at or above 5 mg/L ensures fish survival during
transport by preventing hypoxia stress and mortality. Lower levels can cause gill damage,
suffocation, and increased susceptibility to disease .*
9. What is the most humane method for a Technician to euthanize a small invasive fish
species that cannot be released?
A) Leaving it on the stream bank to dry out
B) Placing it in a freezer to cool down slowly
, C) Administering a sharp blow to the head
D) Releasing it into a different water body far away
✅ Correct Answer: C
Rationale: A swift, forceful blow to the head causes immediate insensibility and humane
death. Leaving fish to dry out or slow-freezing causes prolonged suffering, and releasing
invasive species is illegal .
10. Which parasite, commonly found on trout gills, is a monogenean flatworm requiring
microscopic identification?
A) Anchor worm (Lernaea)
B) Gyrodactylus
C) Sea louse (Lepeophtheirus)
D) Fish louse (Argulus)
✅ Correct Answer: B
Rationale: Gyrodactylus is a monogenean flatworm parasite infecting trout gills and skin.
It causes irritation, excessive mucus production, and secondary infections in hatchery
settings, requiring microscopic identification .
11. What is a "seine net" most commonly used for by Fish and Wildlife Technicians?
A) Capturing a single large trophy fish for tagging
B) Capturing a sample of multiple fish for population assessment
C) Catching birds for banding and release
D) Collecting aquatic insects from the substrate
✅ Correct Answer: B
Rationale: Seine nets are long, vertical nets with weights on the bottom and floats on top.
They are deployed to encircle and capture a sample of multiple fish in shallow waters for
population sampling and assessment .
12. The term "anadromous" describes fish species that exhibit which life cycle pattern?
A) Live entirely in freshwater lakes and rivers
B) Migrate from sea to freshwater to spawn
Certification Exam 2026 – 300 Questions with
Answers & Rationales
Section 1: Fish Hatchery Operations & Fisheries Management (Questions 1–50)
1. When backfilling stream habitat structures such as log or boulder placements during
restoration work, what is the correct technique to ensure long-term stability?
A) Leave large rocks loose to allow natural shifting
B) Compact soil in layers around and under the structures
C) Use clay exclusively to seal all gaps completely
D) Remove all riparian vegetation before backfilling
✅ Correct Answer: B
Rationale: Layered compaction around in-stream structures stabilizes them against high
flows and significantly reduces erosion potential over time .
2. A Fish and Wildlife Technician observes a large fish kill in a freshwater lake during
mid-summer. The water has a greenish scum on the surface. What is the most likely
primary cause?
A) Overpopulation of predatory birds
B) Toxic algal bloom (cyanobacteria) producing hypoxia
C) Introduction of a non-native predatory fish species
D) Sudden drop in water temperature
✅ Correct Answer: B
Rationale: Greenish scum on the water surface during summer indicates a cyanobacterial
(blue-green algae) bloom. When such blooms die, their decomposition consumes
dissolved oxygen, causing hypoxia and fish kills .
3. What is the primary purpose of a fish raceway in a hatchery setting?
A) To separate different species for breeding isolation
B) To aerate water before it enters the main facility
,C) To confine and rear fish in a controlled flowing-water environment
D) To filter debris and sediment from incoming water
✅ Correct Answer: C
Rationale: Raceways are long, narrow channels that provide continuous water flow, which
is essential for oxygenating and carrying waste away from high-density fish populations.
This controlled environment maximizes rearing efficiency .
4. You are electrofishing for a population survey in a stream. What is the most critical
safety concern you must constantly monitor?
A) Risk of slipping on wet algae-covered rocks
B) Electrical current passing through water is dangerous to humans
C) Losing expensive sampling equipment in deep pools
D) Disturbing natural sediment and reducing water clarity
✅ Correct Answer: B
Rationale: Electrofishing uses electrical current to temporarily stun fish for capture and
study; the same current is dangerous or fatal to humans if safety protocols like insulated
waders are not followed .
5. In hatchery operations, which bacterial disease is most common in trout and caused by
Aeromonas salmonicida?
A) Chilodonella
B) Furunculosis
C) Ichthyophthirius
D) Anchor worm infestation
✅ Correct Answer: B
Rationale: Furunculosis is a prevalent bacterial disease in salmonid hatcheries caused by
Aeromonas salmonicida. It causes lesions and internal organ damage, requiring prompt
water quality and treatment management .
6. A fish ladder is installed at a dam primarily to achieve what objective?
A) Divert water for agricultural irrigation systems
B) Filter debris and sediment from the water flow
,C) Enable fish to bypass barriers and migrate upstream
D) Measure flow velocity for hydroelectric generation
✅ Correct Answer: C
Rationale: Fish ladders allow migratory fish such as salmon and steelhead to swim
upstream past obstructions such as dams, reaching critical spawning grounds that would
otherwise be inaccessible .
7. The life stage immediately after a fish hatches from its egg is called:
A) Fry
B) Juvenile
C) Alevin
D) Fingerling
✅ Correct Answer: C
Rationale: The alevin stage begins immediately after hatching. Alevins still have their yolk
sac attached, which provides nutrition until they absorb it and become fry. Fry then
develop into fingerlings and then juveniles .
8. When transporting live fish between facilities, what is the minimum dissolved oxygen
level that must be maintained in transport water?
A) 2 mg/L
B) 5 mg/L
C) 8 mg/L
D) 10 mg/L
✅ Correct Answer: B
*Rationale: Maintaining dissolved oxygen at or above 5 mg/L ensures fish survival during
transport by preventing hypoxia stress and mortality. Lower levels can cause gill damage,
suffocation, and increased susceptibility to disease .*
9. What is the most humane method for a Technician to euthanize a small invasive fish
species that cannot be released?
A) Leaving it on the stream bank to dry out
B) Placing it in a freezer to cool down slowly
, C) Administering a sharp blow to the head
D) Releasing it into a different water body far away
✅ Correct Answer: C
Rationale: A swift, forceful blow to the head causes immediate insensibility and humane
death. Leaving fish to dry out or slow-freezing causes prolonged suffering, and releasing
invasive species is illegal .
10. Which parasite, commonly found on trout gills, is a monogenean flatworm requiring
microscopic identification?
A) Anchor worm (Lernaea)
B) Gyrodactylus
C) Sea louse (Lepeophtheirus)
D) Fish louse (Argulus)
✅ Correct Answer: B
Rationale: Gyrodactylus is a monogenean flatworm parasite infecting trout gills and skin.
It causes irritation, excessive mucus production, and secondary infections in hatchery
settings, requiring microscopic identification .
11. What is a "seine net" most commonly used for by Fish and Wildlife Technicians?
A) Capturing a single large trophy fish for tagging
B) Capturing a sample of multiple fish for population assessment
C) Catching birds for banding and release
D) Collecting aquatic insects from the substrate
✅ Correct Answer: B
Rationale: Seine nets are long, vertical nets with weights on the bottom and floats on top.
They are deployed to encircle and capture a sample of multiple fish in shallow waters for
population sampling and assessment .
12. The term "anadromous" describes fish species that exhibit which life cycle pattern?
A) Live entirely in freshwater lakes and rivers
B) Migrate from sea to freshwater to spawn
