Humans have put a lot of obstacles in the way of fish wishing to migrate and spawn. A new 'Fitbit for Fish' will test just how stressful their journeys are.

Could the bodily fluids of sea creatures contain clues on how to best preserve our oceans?

Global consumption of fish is outpacing natural production, posing a significant threat to marine ecosystems. Commercially valuable species such as tuna, swordfish, marlin, cod, halibut, skate, and flounder are fished at enormous quantities to the point where populations of said species are dangerously low.