Second Derivative Test

You decide to go deep-sea fishing at your favorite spot $10$ miles off the coast of Miami, Florida. The density of fish per cubic mile in your favorite fishing spot is modeled as a function of time $t$ where $t$ is the number of hours elapsed that day since midnight (that is, $0 \leq t \leq 24$). If this model function is

$$\rho(t) = 2t^3 - 99t^2 + 1560t + 200,$$

then at what time of day will the chosen fishing spot have the highest density of fish?