There are 150 tonnes of fish in this one haul. It used to take a fishing vessel one whole year to catch this many fish. These are mostly yellowfin tuna, plus some skipjack. As they're slower breeders than skipjack, many yellowfin are caught before they're old enough to breed. This makes them more vulnerable to over-fishing. Tuna fishing has grown into an 8-billion-dollar industry. And over 4 million tonnes of tuna are caught worldwide each year, a four-fold increase in as many decades. Almost 2/3 of the catch now comes from the Pacific. In the Atlantic, yellowfin catches have been shrinking since 1990. Now a similar decline has begun in the Pacific. Tuna need to swim constantly to keep water flowing over their gills, otherwise they can't breathe. The fishermen want to get them out of the water as quickly as possible. When starved of oxygen, a build-up of lactic acid in their muscles causes the quality of their meat to deteriorate.


这一批渔获共有150吨，相当于早期每艘渔船一年的渔获量。这里面多数是黄鳍鲔（念wěi ，金枪鱼的一种）和鲣鱼。因其繁殖速度较鲣鱼慢，所以捕到的黄鳍鲔多未成熟。这导致它们更容易因滥捕而锐减。捕捞金枪鱼已发展成为一项产值达80亿的产业。全球每年的金枪鱼捕获量超过四百万吨，几十年来渔获量增加了四倍。其中近三分之二来自太平洋。大西洋的黄鳍鲔产量自1990年开始减少。现在太平洋的渔获量也呈现出类似的下降趋势。金枪鱼必须不断游动，让水流过鱼鳃，否则它们就无法呼吸。渔民要尽快把它们弄出水面。如果缺氧过久，金枪鱼肌肉内部形成的乳酸会使肉质变差。