The most important fishing grounds of the world are found in the regions where warm and cold oceanic currents meet.

Here's why:

Nutrient-rich waters: When warm and cold currents converge, a process known as upwelling occurs. This upwelling brings nutrient-rich deep ocean water to the surface. These nutrients act like fertilizer for plankton, which forms the base of the marine food chain.

Abundant Marine Life: The abundance of plankton attracts a vast array of fish species, making these areas highly productive fishing grounds.

Examples include:

1. The Grand Banks (Newfoundland) - Labrador Current (cold) meets the Gulf Stream (warm)
2. The Humboldt Current (South America) - Cold, nutrient-rich current flowing up the western coast
3. The Canary Current (West Africa) - Cold, nutrient-rich current flowing up the western coast