In the North Pacific subtropical gyre, converging currents concentrate floating debris into a broad region often called the Great Pacific Garbage Patch. The material is mostly plastic—fragments, fishing gear, and larger objects—distributed throughout the surface mixed layer rather than forming a solid island of trash.

Concentrations are higher than in surrounding waters, yet the debris remains widely dispersed and often lies just below the surface, making it difficult to see from ships or satellites. Organisms can ingest the plastic or become entangled; chemical contaminants can also hitchhike on the particles. Similar accumulation zones exist in other subtropical gyres.

Cleanup at sea is challenging because of the scale and the dilution of the debris. Preventing plastic from entering the ocean through better waste management, reduced single-use plastics, and improved fishing-gear recovery is widely regarded as the more effective long-term strategy. Scientific surveys continue to refine estimates of the amount and distribution of plastic in the patch and beyond.

Much of the plastic is broken into small pieces that are harder to recover than large visible objects.