He himself has a warehouse with an estimated half a million dollars of unsellable wool.

自己有一个仓库，里面估有50美元的羊毛卖不出。

And they have learned how to handle diseases better, reducing the quantity of fish that ends up being unsellable.

而且会了怎么控制鱼类的疾病，从而减少了最后无法卖出的鱼的数量。