A scientist found that when an invasive species was introduced into a river, the population of salmon native to the region decreased. The type of correlation between these two populations could best be described as ________.

The type of correlation between the introduced invasive species and the decrease in the native salmon population could best be described as an inverse relationship. When one population increases (the invasive species), the other population (the native salmon) decreases. This suggests that there is a negative relationship between the two populations, where changes in one population are associated with opposite changes in the other population.