
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A biologist wishes to estimate the fish population in a protected area. Initially, on March 1st, she captures and tags 80 fish, then releases them back into the water. Four months later, on July 1st, she captures another 90 fish for a follow-up study, finding that 4 of these are tagged. For her estimation, she assumes that 30% of these fish have left the area by July 1st due to various environmental factors, and that an additional 50% of the fish in the July sample weren't in the area on March 1st due to new arrivals. How many fish does she estimate were in the area on March 1st?

Present the answer in LaTex format: \boxed{Your answer}
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