Question

use the information given to answer the question
the table shows data collected from a study of a river ecosystem located in the northwestern united states. the data was collected at 10 - year intervals from 1955 - 2015
which factor is most likely responsible for the change in the perch population seen from 1975 - 2015?
mutualism with the bass population
parasitism by the algae population
competition with the bass, black bear, and hawk populations
predation by the bass, black bear, and hawk populations

Explanation:

Mutualism means both species benefit. Perch population is decreasing, so mutualism with bass (whose population is increasing) is unlikely. Algae are plants (producers), and parasitism by algae on perch is not a common ecological interaction. Competition would involve resource - sharing issues. But the more likely factor is predation. As bass, black bear, and hawk populations (especially bass which is a fish - eating species) increase over time (bass from 85 in 1975 to 680 in 2015), the perch population (860 in 1975 to 80 in 2015) decreases, which is consistent with a predator - prey relationship.

Answer:

predation by the bass, black bear, and hawk populations