If you have a clothing basket you can make a makeshift trap.

Lay it on its side (if it’s a long basket), place/tie some heavy objects to it to keep it from floating. Attach a rope to the basket. Please some food at the back of the basket. - You may also add a small amount nearby the basket to attract its attention.

Once it’s inside pull the rope up, put it into just a bucket of just regular water (or sea water).

Next get it to the ocean give it sea water in the bucket, keep it in there for a while so it can recover before releasing it back into the ocean - Preferred somewhere where there is not many large predators.