Hadn't considered the salinity issue,
but,
of course, the IOC have prepared the way,
with the Open/Sea swimming.
Pondering further, we could have a four-year relay of whales circumnavigating the oceans,
and,
delivering a (representative) Olympic Torch to the next venue.
They would be excluded from competition due to pool salinity regulations. Unless they can train in freshwater?
I think they could compete in diving as I believe the diving pool is sanitised with salt not chlorine for improved visibility on TV.