A hermit crab found on Southwater Caye in Belize using a bottle cap as a shell. Of course this is indicative of a two fold problem. - a lack of available size-appropriate shells caused in part by increased shell collecting. - too much trash available.
Researchers Map Plastic Debris in Pacific Ocean By Rick Pantaleo :: Plastic ocean debris littering Hawaiian shoreline. Hawaii is located near the center of the North Pacific gyre where debris tends to concentrate.
Increasing human population has led to an increase in POLLUTION. Some of this is due to: more fossil fuels being burned for heat and power, more food being grown, land taken over for industry and housing.