Wild salmon spend most of their lives in the ocean but return to freshwater rivers to spawn, or reproduce. Most wild salmon will only spawn in specific spawning grounds in the rivers in which they were born. The construction of hydroelectric dams in rivers has blocked the paths of some salmon returning to their spawning grounds. This has led to population declines. Which method would be most effective in preventing further wild salmon population declines caused by the construction of hydroelectric dams? A. monitoring genetic diversity by using netting to catch salmon and obtain genetic samples B. observing the migration patterns of wild salmon by tagging and tracking a small sample of fish C. establishing protected regions around wild salmon spawning grounds in specific rivers D. constructing passageways next to dams to allow salmon to swim around blocked rivers

D.

Explanation:

D. constructing passageways next to dams to allow salmon to swim around blocked rivers

This program is already being used in many dammed rivers in the northwest and is showing success.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.