This looks interesting – really big robot fish being used as sensing devices. Shades of Stingray, perhaps?
See Robot fish detects pollution – technology | Stuff.co.nz.
For those of you who missed out on Stingray in your childhood, here’s a link to the TV show’s title sequence. (Always had a soft spot for ‘scifi’ submarine/underwater shows like Sealab 2020, Man from Atlantis, Stingray and Voyage to the Bottom of the Sea. Though, somehow really didn’t get into seaQuest DSV)