The rampant mercury in high food chain fish that are depleting, and with others, too, is bad enough.
From a previous thread:
Still, the 6 huge oceanic trash gyres(2 in the N Pac, 1 S Pac, 1 N Atl, 1 S Atl, & 1 Ind), and the over-fishing to depletion by 2035-50, the 100 estuary dead zones, and the mercury pollution (mostly from China) to the oceanic food chain are caused by many coastal and island countries, and the water circulates as it is getting more acidic to the CO2 saturation point and warmed to the point, eventually, of massive methane releases.
I wrote Gore in '95 that we needed to torpedo the drift netters, among other things to reduce the population and pollution. I got a form letter back.