Answer:
Calculating the population after 8 years with a 5% decrease annually:
\[ P = 49,000 \times (1 - 0.05)^8 \]
\[ P \approx 49,000 \times (0.95)^8 \]
\[ P \approx 49,000 \times 0.66342 \]
\[ P \approx 32,466.58 \]
Therefore, the estimated fish population after 8 years is approximately 32,467.