Seeing as the European eel population has shrunk by 95% over the past 25 years:

Europe's Eels Are Slipping Away, Scientists Warn
http://news.nationalgeographic.com/news/2003/10/1009_031009_endangeredeels.html

Eels in crisis after 95% decline in last 25 years
http://www.guardian.co.uk/environment/2009/may/01/eel-fishing-europe-environment

Eel conservation is of paramount importance, and as anglers we can do out bit to help the eel by releasing any eels we catch.

Also, the EA is drafting new bylaws to regulate commercial eel fishing, and rod and line angling.
The consultation on commercial eel fishing ends on 7/7.
The one on rod and line fish removal ends on 14/7.
Please consider sending them your views on this, see:
http://www.fishing-4-life.com/all-other-species-f11/urgent-environment-agency-consultations-on-new-fishing-laws-t25.htm