What do the fish-vs-plastic myths distract us from?

The idea that plastic will outweigh fish in the ocean by 2050 has become one of the most widely-quoted statistics in environmental discussions. But this disguises the real nature of the problem. Fish make up around 29% of animal biomass on this planet (Ritchie 2024) but calculating their mass in oceans is very difficult. We can estimate algae concentrations from satellite imagery - a proxy for fish food - but actual marine biomass remains uncertain and rather variable. Estimating ocean...