First, the Sparkfun Venus is garbage - don't get it! And don't trust the schematic, it didn't match the actual device I bought. Declared specs of the Venus on the Sparkfun website are wrong, too.
That said, I *believe* you have to request the information. Its I2C, so wouldn't make sense that it would transmit non-stop. I'm sure the manual will explain, or someone else can chime in.