Why have marine fish stocks been depleted significantly in the last 75 years?

90% of fish stocks are used up – fisheries subsidies must stop ... Year after year, we have been pushing the boundaries of the ocean's ... Nearly 90% of the world's marine fish stocks are now fully exploited, overexploited or depleted. ... underpinned the dramatic decrease of fish stocks in the last 40 years, ...

Explanation:

ish catches have declined markedly and are likely to fall further, a study has found, with warming oceans to blame. ... The findings come from a study that has used “hindcasting” methods to reconstruct the effects of global warming, overfishing and other impacts on fisheries over the 80-year period from 1930 to 2010

Explanation:

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.