Agriculture has long been one of China's preferred sectors for trade retaliation.

And viral outbreaks (bird flu, swine fever) have long impacted agricultural trade as well.

Looking back at the detailed trade data here is thus interesting, even now https://www.cfr.org/blog/how-effective-have-chinas-agricultural-and-seafood-tariffs-been

Blog looks at China's tariffs on chicken feet (and bird flu), China's tariffs on soybeans (unambiguously had a big impact), the impact of swine flu on pork exports (rose well ahead of the "deal") --

And to keep it interesting, that most tasty crustacean, the lobster

China's 09 tariff on U.S. chicken parts actually did not have an impact ...

Exports to China fell, but exports to HK rose almost dollar for dollar. It isn't well known, but this is about a clear a case of trade diversion as there is.

Swine fever, on the other hand, led China's imports of pork from the U.S. to soar even before the phase 1 trade deal in January (to be fair, China's imports from Brazil and Europe are up even more in dollar terms)

And by literally zeroing out its 'bean imports during the normal seasonal peak in 2018, China showed that it can damage U.S. agricultural interests when it is serious -- even in what basically is a bulk commodity.

Conversely, at least in my view, the impact of China's retaliatory tariffs on lobsters (crustaceans in the trade data, but that's primarily lobster) was often a bit over stated.

Exports to China fell in 18 and 19 -- but overall exports have held up.

There was a pretty obvious workaround to the tariffs in 2018 --

China bought more Canadian lobster, and less U.S. lobster.

And the U.S. exported more lobsters to Canada, as Canadians like eating lobster too

2019 was a bit different -- the Maine lobster season was a bit late, and it was smaller than usual.

So the U.S. ended up importing more Canadian lobster than usual ...

A smaller lobster harvest meant higher prices, fewer overall exports, and much higher "net" imports of lobster from Canada ....

(net imports are US imports of Canadian crustaceans minus US exports of crustaceans to Canada)

Main point here is that it is important to look at the overall trade data - not just the bilateral trade data - when assessing the impact of many retaliatory tariffs.

(And on a serious note, COVID 19 has had a huge impact on Canada's lobster trade. Prices are now down)