This is an interesting piece by the CBC on a breakthrough with satellite archival tags on one of the Atlantic Ocean's most mysterious creatures: eels.
They've come under a tremendous amount of pressure over the past 30 years, with overharvesting of the larvae — considered a delacacy in Asia — in places like Maine and Canada. The larvae often sell for more than $5,000 per pound — but that's lots of little eels.
Interestingly enough, their experience with the eels getting eaten — $4,000 satellite GPS tags and all — closely reflects the experience of Don Hammond at the Dolphin Tagging Project.