Optimism and the Yangtze River dolphin

ABC (Australia) is reporting that the Yangtze River dolphin or baiji (Lipotes vexillifer) may not be definitely extinct after all (see here and here). Wang Ding - who headed the survey team - is reported as saying:

This is only one survey and...you can’t have a sample in a survey, so you cannot say the baiji all is gone by the result of only one survey. For example, there is some side channels or some tributaries [where] we cannot go because of a restriction of navigation rules, and also we don’t survey during the night-time so we may miss some animals in the Yangtze River. ...

I’m pretty much sure there are a few of them left somewhere in the Yangtze River. I keep receiving reports from fishermen, they say they saw a couple of baiji somewhere, sometime. But unfortunately most of them cannot be confirmed, and the Yangtze River is a big river, so I really cannot say the Baiji is already gone, there is no baiji left at all, I really cannot say that.

Well, of course you cannot say that no baiji are left. But it certainly looks like the species is for all intents and purposes extinct. It sounds more like Ding wants the species to survive but doesn’t have any decent evidence that it does. Misplaced optimism, if you ask me.