One day cruise on Rhone from Arles to Martigues?

I am 99.9% sure that there is no such thing. Martigues is not at the mouth of the Rhône anyway, and it is of limited interest to most travellers.
However I believe there are much shorter excursions on an arm of the Rhône available from Les Saintes Maries de La Mer, which is a 40 minute drive away.

Thanks, Balso. Perhaps I will rethink the question and in case you can answer it, thanks in advance. Without a car, and using Aix as a home base, or Avignon as a home base, are there one day river cruises that go to another place that you would recommend for a day trip? We will be coming to Aix from a few days in Arles, so I won't be interested in a cruise to Arles. Esther

The short answer is no, there are no regular point to point cruises on the Rhône river besides the multiday cruises operated by companies such as Viking. Nothing like on the Rhine between Cologne and Mainz for instance.
Besides, apart from Arles and Avingnon there aren't any interesting towns directly on the river, and the river isn't too scenic in that region - it is very much channelled.

OK, that puts that idea to rest. I appreciate your advice; it saved me a lot of aggravation!