illegal fishing; illegal operation
Refers to fishing or other marine operations conducted without proper authorization or in violation of regulations. Often used in news reports about poaching or unlicensed vessels.
Crackdowns on illegal fishing have been strengthened.
Illegal operations by foreign vessels have become a problem.
密漁 specifically means poaching or illegal fishing, often with a nuance of stealth. 違法操業 is a broader term that can include any illegal operation, not limited to fishing.
Compound of 違法 (illegal) and 操業 (operation). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning.