CFP Fish Biology & Physiology 2 — Questions and Answers
Question 1: Which migratory life history pattern describes fish that hatch in freshwater, migrate to the ocean to grow, then return to freshwater to spawn?
- Catadromy
- Anadromy (Correct answer)
- Diadromy
- Amphidromy
Correct answer: Anadromy
Anadromy describes the pattern seen in salmon and shad, where fish are born in freshwater streams, migrate to the ocean for growth, and then return to freshwater to reproduce.
Question 2: What is the primary function of pyloric caecae in bony fishes?
- Producing bile acids to emulsify dietary fats
- Increasing absorptive surface area for nutrient uptake (Correct answer)
- Filtering metabolic waste from the bloodstream
- Regulating water uptake from ingested food
Correct answer: Increasing absorptive surface area for nutrient uptake
Pyloric caecae are finger-like pouches at the pyloric junction of the stomach and intestine that significantly increase digestive surface area, enhancing the absorption of nutrients from digested food.
Question 3: What type of scales are exclusively characteristic of cartilaginous fishes such as sharks and rays?
- Cycloid scales
- Ctenoid scales
- Placoid scales (Correct answer)
- Ganoid scales
Correct answer: Placoid scales
Placoid scales (dermal denticles) are tooth-like dermal structures found only in cartilaginous fishes; they are structurally similar to vertebrate teeth and give shark skin its characteristic rough texture.
Question 4: In ovoviviparous fish reproduction, how does embryo development occur?
- Fertilized eggs are deposited externally and develop in the environment
- Eggs are retained internally and young are born live, nourished by egg yolk (Correct answer)
- Young develop internally and receive nutrients through a placental connection
- Females carry fertilized eggs in their mouths until hatching occurs
Correct answer: Eggs are retained internally and young are born live, nourished by egg yolk
In ovoviviparity, fertilized eggs are retained inside the mother's body where they develop nourished by yolk reserves, with live young born after internal hatching — as seen in many sharks and rockfish.
Question 5: What is the role of the oil globule found in the eggs of many pelagic fish species?
- Providing a protective coating against pathogens
- Providing buoyancy and serving as an energy reserve for the embryo (Correct answer)
- Attracting sperm during fertilization
- Regulating osmotic pressure inside the egg
Correct answer: Providing buoyancy and serving as an energy reserve for the embryo
The oil globule in pelagic fish eggs provides positive buoyancy to keep eggs in the water column and serves as a lipid energy reserve that fuels embryonic development and early larval stages.
Question 6: What physiological transformation does the term 'smoltification' describe in juvenile salmon?
- Sexual maturation and development of spawning coloration
- Transformation from freshwater-adapted parr to seawater-ready smolt (Correct answer)
- Development of territorial behavior prior to nest building
- Transition from larval to juvenile feeding behavior
Correct answer: Transformation from freshwater-adapted parr to seawater-ready smolt
Smoltification is the complex hormonal and physiological transformation that prepares juvenile salmon (parr) for life in seawater, involving changes in gill structure, body coloration, behavior, and osmoregulatory capacity.
Question 7: Besides their role in hearing and balance, how are fish otoliths used by fisheries scientists?
- To determine genetic relatedness between populations
- To estimate individual fish age using annual growth rings (Correct answer)
- To assess reproductive condition and fecundity
- To measure historical pollution exposure through chemical analysis only
Correct answer: To estimate individual fish age using annual growth rings
Otoliths accumulate calcium carbonate in daily and annual increments (annuli), creating growth rings analogous to tree rings that allow fisheries biologists to accurately determine fish age.
CFP Fish Biology & Physiology 2
Which migratory life history pattern describes fish that hatch in freshwater, migrate to the ocean to grow, then return to freshwater to spawn?