Like Bear Paw Lake, nearby Kalmbach Lake is an Alaskan lake that historically had no native predatory fish. The Alaska Department of Fish and Game started introducing rainbow trout into Kalmbach Lake in 1982. Prior to these introductions, pelvic reduction was common in this stickleback population. The rainbow trout is known to prey on stickleback. What would you hypothesize has happened to the stickleback population in the more than 30 generations that have elapsed since the trout was introduced? Question 6 options:

All the stickleback fish in Kalmbach Lake perished.

The population size of stickleback fish dropped dramatically, leaving only a few survivors, all of which have the absent pelvic phenotype.

Most stickleback fish in Kalmbach Lake now have pelvic spines.

Kalmbach Lake has no native predatory fish.