4 June 2009 - The most edible of Dutch delicacies, the eel, is under threat. This mysterious fish travels thousands of miles to spawn in the Sargasso sea but lives most of its life in freshwater rivers and lakes in Europe.

Stocks are declining at an alarming rate, and are 100th of what they were 20 years ago. So who's to blame and what's being done about it? We follow fishermen as they release eels in an effort to restock. Conservation groups think that this isn't enough and the only way to save this species from extinction is to keep it off the supermarket shelves.

 
Also on the show - mosquitos in Galapagos develop a taste for reptile blood, compost-friendly styrofoam, and the mystery of why soil makes plants grow.