We’re eating more fish than ever these days. At around 20 kilograms per person global fish consumption is now more than twice what it was in the 1960s. What’s really remarkable, though, is where that fish comes from.

        For the first time in human history, most of our aquatic (水产的) food now comes from farming rather than fishing.

        People ate around 73 million tonnes of farmed fish—just more than half of the volume of fish that humans consumed—in 2014. That’s out of a total fish supply of 167 million tonnes; the remaining 20 million or so tonnes go into things like animal feed and medical products.

        To keep eating fish at the current rate, we’re definitely going to need to keep aquaculture (水产养殖) developing. That’s because the volume of fish caught in the wild has leveled off since the 1990s.

        Back in 1974, only 10% of marine fish stocks had been overfished. Now, more than three-tenths are. Only a tenth of our oceans’ fish stocks could sustain heavier fishing than current levels.

        But while catchings at sea have suffered, fish-farming has been growing at a fast rate. A lot ofthat is coming from China, which produces 60% of the world’s farmed fish. In fact, some 35 countries, including China, now produce more farmed than wild-caught fish.

        This shift toward aquaculture isn’t just good for ensuring salmon (三文鱼) on your plate; it’s also crucial to ensuring food security and sustainability. By 2050, the world will need to feed an estimated 9.7 billion people. They’ll have to get their protein somewhere. However, raising cattle, pigs, and other land-based animals requires vast sums of grain and water. For example, pound for pound, beef requires 15 times more feed to raise than carp, a freshwater fish farmed all over Asia. That grain—and the water needed to grow it—could be consumed by people instead.

        However, aquaculture is no silver bullet. In some southeast Asian countries, shrimp farming does disastrous damage to marine ecosystems. Despite these problems, however, shrimp continues to be among the most popular seafoods worldwide.

解析：C。根据题干中的aquaculture is no silver bullet可定位至原文最后一段。该段前两句提到，水产养殖并不是一劳永逸之计，在一些东南亚国家，虾类养殖对海洋生态系统造成了灾难性的破坏。由此可知，作者认为水产养殖也存在弊端。C项与此相符，其中的cause serious problems对应原文最后一段第二句中的does disastrous damage，故为正确答案。

错项排除：原文中只提到虾类养殖给海洋生态系统造成了灾难性破坏，没有提到虾类养殖风险很大或鱼类养殖是不可持续的，故排除A项和B项。D项中的quite expensive在原文中无依据，故排除。