http://www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/MBA_SeafoodWatch_SushiGuide.pdf
I really encourage sushi lovers to check out this guide to sustainable dining. A lot of what is served at sushi restaurants could be part of a highly unsustainable fishery. The guide lists the good (sustainable) items, the good alternatives (fairly sustainable choices), and the items to avoid.
D'oh -- freshwater eel (unagi) and octopus are in the "avoid" column.
Saltwater eel (anago) doesn't seem to be on that list, along with some other stuff I like.
Two of my favorites as well. The thing is that freshwater eels have complex life-cycles (involving a massive migration out to the Sargasso Sea in the Atlantic), and when a sea-animal has a complex life-cycle it's actually really, really easy to put them in a bad spot with overfishing.Octopus is my favorite!