Know your prey

So, you think you know a few things about salmon. These 10 questions will put your knowledge to the test.


1. The thick, dark substance located between the swim bladder and the spine of a salmon is:

a. coagulated blood

b. kidney

c. spinal fluid

2. The fin farthest away from a salmon’s head is the:

a. caudal fin

b. adipose fin

c. anal fin

3. A salmon’s lateral line:

a. secretes slime that aids in preventing bacteria from entering its skin

b. senses low-frequency vibrations in the water

c. works in conjunction with its swim bladder to allow the fish to make rapid changes in depth.

4. The thin, dark layer of flesh just beneath the skin on a salmon’s side is:

a. waste matter and fat cells that eventually are excreted through the skin

b. a reservoir for chromatophores, the specialized cells that change the color of the skin as it nears spawning time.

c. red muscle fibers

5. A salmon uses its fins:

a. to steer

b. to propel it through the water

c. to brake

d. all of the above

6. Balance, orientation and hearing are functions of a salmon’s:

a. otoliths

b. peduncle

c. pyloric caeca

7. As spawning time approaches, a male salmon will sometimes use this to defend its spawning area:

a. kype

b. axillary process

c. gill rakers

8. Part of a salmon’s olfactory system that help it to locate its native stream is its:

a. swim bladder

b. axillary process

c. nares

9. The chinook salmon was named for:

a. Edgar Ward-Worthington Chinook, a scout for Lewis and Clark who first “discovered” the fish.

b. the Chinook Natives who lived along the lower and middle Columbia River.

c. the chin hook, a fishing technique used to catch salmon that are reluctant to bite.

10. The sockeye salmon was named for:

a. its large eyes

b. a misspelling of Sachia Hasagawa, the fisherman responsible for developing the chin hook fishing technique.

c. “sukkai,” an anglicized version of various American Native words for the sockeye.


1. b. Kidney. Actually, salmon have two kidneys that are joined together, so they appear to be only one. The forward kidney produces and replaces red blood cells, and the rearward kidney filters waste from the blood.

2. a. The caudal fin is the tail fin; the adipose fin is the small, fleshy fin on the back, between the tail and the dorsal fin; the anal fin is right behind the anus.

3. b. In the entire animal kingdom, fish are the only animals with a lateral line. This sense organ appears as a thin line of pores, generally along the middle of the side of the body.

4. c. Fish, like birds and mammals, have both red and white muscle fibers. The “slow twitch” red fibers just under the skin of a salmon provide the fish with stamina for continuous cruising. Most of a salmon’s flesh consists of “fast twitch” white muscle fibers. These are used for occasional bursts of speed, such as escaping from predators.

5. d. The dorsal fin provides steering control and balance. The pectoral and pelvic fins aid in braking, stabilization and maneuvering. The anal fin provides balance. The caudal, or tail fin is the main source of propulsion, and also is used for braking. A fish “puts on the brakes” by extending its pectoral fins, curling its tail in one direction and its dorsal and tail fins in the other.

6. a. Fish have three pairs of otoliths. These “ear bones” are made of calcium carbonate — limestone — and protein. Salmon otoliths are useful in determining various information about age, growth rate, life history, recruitment and taxonomy, and play an important part salmon fisheries management. The otoliths of humans are much smaller than those of fish. Humans sometimes wear ear-rings made of fish otoliths.

7. a. A mature male salmon defending its spawning territory will sometimes bite other male salmon with its hooked jaw, its kype.

8. c. A salmon’s nares, or nostrils, lead to its olfactory organs, part of its well-developed sense of smell. The olfactory sense forms the largest part of a fish’s brain.

9. b. Chinook Natives were encountered by the Lewis and Clark Expedition in 1805.

10. c.

How did you score? If you answered four or more incorrectly, you can’t fish for salmon this year. Instead, you should spend the summer studying up on fish. There’s always another year.


“The Freshwater Fishes of Alaska,” by James E. Morrow

“Through the Fish’s Eye,” by Mark Sosin and John Clark

“Trout and Salmon of North America,” by Robert J. Behnke

Otolith and Thermal Marking Laboratory, Alaska Department of Fish and game.

Les Palmer can be reached at