Why was the captain anxious?

The Captain was anxious when he saw the emigrant ship on its way to America, and that it carried people he knew.

We put the ferry-boat alongside, and the exiles leaned over the bulwarks, weeping and reaching out their hands to my fellow-passengers, among whom they counted some near friends. How long this might have gone on I do not know, for they seemed to have no sense of time: but at last the captain of the ship, who seemed near beside himself (and no great wonder) in the midst of this crying and confusion, came to the side and begged us to depart.