Glass sculpture to raise awareness in support of sustainable aquaculture. Overfishing is when fish are caught faster than their stocks can be replenished, leading to an overall depletion of fish populations. Another problem related to overfishing is bycatch, whereby large amounts of unwanted sea animals are captured during the fishing for a particular species and discarded as waste. Coral reefs are particularly vulnerable to overfishing. Plant-eating fish keep these ecosystems in balance by eating algae, keeping the coral clean and healthy so that it can grow. Fishing out too many herbivores—whether intentionally or as bycatch—can weaken reefs. and upset the ancient and delicate balance of the sea's biological system. Not only does overfishing pose a threat to the marine ecosystems, but it also affects people directly, researchers have found that Illegal, unreported, and unregulated fishing relate to serious problems like human trafficking and slavery at sea. In Britain, we’re creatures of habit when it comes to seafood. The Marine Conservation Society reports that 80 percent of all seafood sold in the UK comprises of just five varieties: salmon, cod, haddock, prawns, and tuna.