There were both some huge gains and losses on the CW network. Despite the fact that there are just a few more episodes of Smallville left, the ratings took a huge dive. Supernatural fell almost as much. Nikita fell once again and the timing couldn’t be worse. Conversely, America’s Next Top Model saw a huge gain and Vampire Diaries’ wasn’t too shabby either.

Which CW TV shows will be cancelled or renewed depends mostly on the series’ ratings. The network puts a lot of importance on the female 18-34 demographic where most others focus on the 18-49 demo. Before we get to the season-to-date averages, here are the winners and losers from April 21st through April 28th — based on the 18-34 female demo, as measured against the last original episode.

Week-to-Week Gains: Gossip Girl 1.7/5 (+6.2%), America’s Next Top Model 1.8/5 (+63.6%), and The Vampire Diaries 1.9/6 (+26.7%).

No Change: One Tree Hill 1.3/4

Week-to-Week Losses: Smallville 0.5/2 (-37.5%), Supernatural 0.6/2 (-33.3%), 90210 1.3/4 (-13.3%), Hellcats 0.7/2 (-12.5%), and Nikita 0.7/2 (-12.5%).

Wonder if your favorite CW show’s been renewed or cancelled? Check out our comprehensive list. We’ll keep updating it as new info becomes available.

Below is a list of the regular CW TV shows and their 2010-11 season average ratings to date. It only incorporates the ratings for original episodes and not repeats. The data is sorted by the 18-34 female demographic averages. The closer a show is to the bottom, the more likely it is to be cancelled. Friday is one of the least-watched nights of TV so those shows are expected to get lower numbers.

Raw data: © The Nielsen Company via Media Week.

What do you think? Any surprises? Which shows do you think won’t survive to see a new season?

Image courtesy CW.