Wave Race: Blue Storm is a jet ski racing game released as a launch title for the Nintendo GameCube on November 18, 2001. It was a sequel to the 1996 Nintendo 64 game Wave Race 64 and was developed by Nintendo-owned development studio, NST. [Infos from Wikipedia]
When the new Wave Race project for the Gamecube was first shown at the Space World 2000, Nintendo presented a small tech demo with a different graphic style than the one used in the final game, more similar to the Nintendo 64 version. Probably this was just an early concept for the title and the final character design was still undecided.
Also, as noticed by Rusko Star, if you look in the booklet in the released game or in the old videos you can see that Serena had a ponytail in the beta version!