People were no less innovative back then.If the Greeks could build the Antikythera mechanism (http://en.wikipedia.org/wiki/Antikythera_mechanism) I'm sure the Romans could make a water pump to keep their catch fresh.
mike: Now I want to build a water pump. You could build one from recycled materials and hook it to a bicycle to get a serious pump to spray a barrel of rainwater, for example. Here's a good do-it-yourself design, and a nice story of experimental engineering:http://sites.google.com/site/treadlepump/buildyourowntreadle...