Pollution and Poles have naff all to do with eel extinction; they survived 300 years of fyke netting on a huge scale and tons taken as elvers, not to mention a century of appalling river pollution in the Industrial Revolution.
Something much more fundamental is going on, and my guess is that it's something to do with the migration to and from the Sargasso. Ocean currents have changed drastically with global warming, so that might be the cause. Either that or some ecological imbalance due to overfishing - which, incidentally, is the reason Canada is loused out with the lobsters you see, frozen, in Tesco, and why we are having a jellyfish invasion.
I never though that in my lifetime or my kids' there would ever be a shortage of eels. It's a disaster - a barometer that should be warning us there's a big, nasty storm coming....