Are they misleading us on porpoise?

Lots of media outlets are reporting a scientist who is claiming that harbour porpoises are threatened by starvation because of global warming. Changes in sea temperature are causing a reduction in the population of sand eels, apparently, so there's not enough for them to eat.

And how did our scientists reach this conclusion? The Graun newsblog fills us in:

Academics at Aberdeen University and the Scottish Agricultural College, in Inverness, studied the stomach contents of stranded porpoises collected from the east coast of Scotland in the springs of 2002 and 2003.

They found these contained fewer sand eels and other food compared with porpoises recovered between 1992 and 2001. Other research showed that while 5% of stranded porpoises died due to starvation in the late 1990s, 33% starved to death in the springs of 2002 and 2003.

Which is pretty amazing stuff. A study on the contents of porpoise stomachs proves that global warming is the culprit! How do you manage to do that?  Perhaps the author, Colin McLeod of Aberdeen University, is an augur rather than a proper scientist. I wonder if he reads tea leaves too? 

I wonder if perhaps rampant overfishing of sand eels, a well-documented phenomenon if ever there was one, might have played just an eeny weeny part too? Wouldn't get the headlines though, would it?