Although the amount of seafood (fish, shrimps, mussels etc.) produced globally has increased more than 8-fold since 1950, the number of fish caught from the ocean has not increased since the 1990s . The increase in seafood production since then has come entirely from fish farming (also known as aquaculture) . About 47% of global fish production is from aquaculture . Whilst aquaculture means fewer fish are taken out of the sea, it has its own environmental repercussions such as those discussed in our last post on shrimp [2,14].
Fishing techniques and machinery are constantly becoming more sophisticated  – so why aren’t we taking any more fish out of the sea? This is due to the size of fish populations decreasing – we are removing fish faster than they can reproduce . Indeed, 60% of monitored wild fish populations are fully exploited (which means that no more fish could be removed per year without causing the population to collapse), whilst 33% are overexploited (fish are being removed faster than they reproduce, so their number is decreasing) .
Rising sea temperatures and ocean acidification due to climate change, together with chemical and plastic pollution, make it even harder for fish populations to cope with the pressure of fishing [5,6,7,12,13]. This is bad news for marine animals like dolphins and whales that need to eat fish to survive .
The most obvious way to help fish is to eat fewer of them, but this is easier said than done! 3 billion people rely on fish as the main source of protein in their diet  and 38 million people are employed in fisheries and aquaculture . We’ll discuss what we can do about this in the next post.
 http://www.fao.org/state-of-fisheries-aquaculture See: The status of fishery resources; N.B. ‘maximally sustainably fished’ equates to ‘fully exploited’ as shown by http://www.fao.org/3/a-i5555e.pdf and http://www.fao.org/newsroom/common/ecg/1000505/en/stocks.pdf
 https://science.sciencemag.org/content/359/6371/eaam7240.full See: Nutrient enrichment of coastal waters and Climate change in coastal waters
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