What losses did Antonio encounter in The Merchant of Venice?

We first hear the rumor that Antonio has lost one of his ships in the opening scene of act 3. Solanio and Salarino enter the scene discussing the news that one of Antonio's ships, carrying valuable cargo, has wrecked off the English coast. Of course, when Shylock arrives and hears the news he is overjoyed at Antonio's misfortune; now he might have his chance at revenge.
In the following scene, we learn that the situation is even worse for Antonio. Bassanio receives a letter from Antonio informing him that all his ventures have been lost at sea. Of course, since Antonio had borrowed three thousand ducats from Shylock—with his ships as collateral—he would now owe the moneylender a pound of his flesh, as these were the terms of their agreement.
The characters in The Merchant of Venice are acutely aware of the risks involved in shipping. We hear just how dangerous an investment shipping is from Shylock in act 1, scene 3 when he enumerates all the risks to Bassanio, ranging from pirate raids to storms at sea. It is almost as if Shylock expects Antonio to suffer the loss of all his investments.

Being a merchant at that time was a risky business. Just one single storm could be enough to destroy an entire fleet of ships with them their precious cargo. In The Merchant of Venice, Antonio suffers a similarly disastrous loss himself. In act III, scene 1, we discover that one of this merchant ships carrying a particularly valuable load has been wrecked upon the notorious Goodwin Sands, a sandbar off the south-east coast of England. Even worse is yet to come for poor old Antonio in the next scene. Bassanio receives a letter from him which relates the terrible news that he's lost other ships at sea. This is a disaster for Antonio, as it's now a virtual certainty that he won't be able to pay Shylock the money he owes him and so will have to forfeit a pound of flesh.