After a year of explosive audience growth, the cable news channels head into 2009 buoyed by record ratings, a rare bright spot in what otherwise has been a gloomy media season.

Thanks largely to avid interest in the historic presidential campaign, all of the networks scored their largest prime-time viewership in history this year -- although they suffered a steep drop in viewers after the election.

Fox News racked up its seventh straight year as the most-watched cable news channel, delivering an average prime-time viewership of 2.1 million, 40 percent more than 2007, according to data released Tuesday by Nielsen Media Research. CNN placed second with 1.3 million, up 69 percent, while MSNBC drew 920,000, a boost of 82 percent.

With such huge gains in audience, the cable networks rivaled and often beat the broadcast networks with their coverage of the political conventions and presidential debates.

"You really saw the news game move to cable," MSNBC president Phil Griffin said. "I think cable news has come of age."

But even as the cable channels jostle over which can claim the biggest success in the past year, there are already signs of the challenges they'll face sustaining their audiences.

Since Election Day, all three have suffered a marked drop in viewership. Fox News' prime-time audience shrank by 40 percent in the seven weeks since Nov. 4 compared with the six-week period leading up to the election, a loss of 1.37 million viewers. CNN shed 50 percent of its audience, down 1.16 million viewers. MSNBC dropped 41 percent, down 713,000 viewers.

Cable news executives said they weren't surprised by the post-election falloff.

"This was an emotionally wrenching election, and an awful lot of viewers who are not normal news viewers tuned in to see who would win," CNN/U.S. president Jon Klein said.

He and other executives insisted that the coming year will present new opportunities to boost audience as people seek information about the incoming Obama administration and the state of the economy.

"There's plenty of drama out there," Griffin said. "If we lose a lot of our audience, that's our fault."

The competition among the networks is bound to be fierce as they labor to attract viewers in a highly politicized environment. Fox News has solidified its lineup of right-leaning commentators, renewing the contracts of Sean Hannity and Bill O'Reilly and bringing aboard Glenn Beck for a show that begins Jan. 19. MSNBC has gone the other direction, tapping liberal host Rachel Maddow to follow Bush critic Keith Olbermann, whose contract was renewed for four more years.

CNN, sensing an opportunity, has sought to claim the middle ground.

CNN scored significant victories throughout the 2008 campaign, including on election night, when it was the most-watched network in all of television between 5 and 9:30 p.m. Pacific time. "I think we established very clearly that CNN is the network to watch for reliable information," Klein said. In lieu of a response, a Fox News spokesman pointed to the network's ratings dominance.

MSNBC rejected the notion that politics taints the news it delivers. "We don't skew the news," Griffin said. "I don't think we've embraced an ideology, but I do think we've embraced the point of view of our hosts."

After years of trailing far behind, MSNBC is basking in the success of Olbermann, who continues to beat CNN in his time period, as well as new star Maddow, who bested "Larry King Live" in the demographic most valuable to advertisers, 25- to 54-year-olds.

Both networks were outstripped in those time slots by Fox News' "The O'Reilly Factor" and "Hannity & Colmes," which were the two most popular cable news shows of the year, followed by "On the Record With Greta Van Susteren," "The Fox Report With Shepard Smith" and "Special Report With Brit Hume." (Hume, who anchored his last program Dec. 23, will be succeeded by Bret Baier beginning Monday.)

Heather Locklear pleaded guilty to a lesser offense and had her driving under the influence case dismissed, says TMZ.com.

The gossip site reported that the actress pleaded no contest to reckless driving, a misdemeanor. She'll be placed on three years informal probation, pay a $700 fine and attend a 12-hour drug education course.

Locklear was arrested in September after she was allegedly driving under the influence of prescription meds. The D.A. said Locklear's blood tests showed no alcohol was involved.

TMZ wrote, "Score one more for the unbeatable Blair Berk, who seems to work mini-miracles for some of these celebs who cross the legal line. Berk was in Santa Barbara court this a.m. for the plea. Locklear was not there."

Tomorrow's "60 Minutes" will feature a Lesley Stahl report on "mind-reading" experiments by Carnegie Mellon University professors Tom Mitchell and Marcel Just. ... Rick Meneskie, a coal miner from Coal Center, Washington County, will appear as a contestant on "Jeopardy!" (7 p.m., WPXI) Wednesday. (Rob Owen, Post-Gazette TV editor)

First Published: January 3, 2009, 5:00 a.m.