Well that makes sense what you're pulling up. Excellent research.
On the call they noted they had reduced the inventory from 7000t to 5200t (-1800t in July and first half of August), at $16/kg to China. The +600t in July 2021 would probably be all Tassal's, though I would have expected it to be a bit more. It may be going through other ports even if their marketing office is in Shanghai - bare in mind it is Shanghai and Guangzhou that have the air freight restrictions due to Covid at the moment. Also, it could be that some of the growth started in June. In terms of the price, that would be the FOB value and not the revenue to Tassal, so could be some revenue / costs for the freight which explains the difference. Key point though remains that the price has been increasing.
https://salmonbusiness.com/shanghai-and-guangzhou-suspend-seafood-imports/It would be interesting to look at 2019 monthly values. Generally exports in 3Q and 4Q (first half of the year) is better for Tassal as they are competing less with the Europeans. Everything in 2020 was thrown up in disarray as volumes were really high in 1H20 (July-December) while prices were low - and similarly what we are seeing in 1H21 is upside down because of the inability for air freight imports to get into China from most countries.
And just for fun, here's more noise from Forrest on the Huon bid - sore loser.
https://salmonbusiness.com/forrest-defends-low-huon-bid-on-environmental-grounds/