Gary Levin

USA TODAY

With a few notable exceptions, cable networks continued their ratings descent in the first half of 2016, and the biggest losers were those targeting fickle younger viewers, whom advertisers are so desperately trying to reach.

Those younger audiences are more readily watching on their phones or online, and are less likely to subscribe to expensive cable packages, hurting the likes of ESPN, down 4% in prime time this year, dipping below an average of 2 million viewers.

Apart from news and sports, "there's not that urgency anymore to watch live" programming when it airs, says analyst Billie Gold of New York ad firm Dentsu Aegis.

And "if you've chosen to watch video on demand, you're no longer looking for random viewing," says Moffett Nathanson analyst Michael Nathanson, so channel surfing of reruns suffers. "Cable networks have had a hard time adjusting."

On average, 32% of adults ages 18 to 34 watched TV in the winter of 2012; that figure dropped to 26% last winter and 24% this year; teen viewership dropped more steeply, from 27% in 2012 to just 18%.

A look at midyear ups and downs:

Cable news loves the presidential race. With a crowded field of candidates led by ratings catnip Donald Trump, ratings soared for CNN — which jumped 130% in prime time to an average 1.3 million viewers — and Fox News, which supplanted ESPN as the top-rated network with an average of 2.2 million, up 30%. Also-ran MSNBC saw its own big 68% bump, to 885,000.

Viacom woes. The battle to wrest control of the company, controlled by 93-year-old Sumner Redstone, is in part motivated by ratings (and therefore, advertising) tumble among most of its youth-targeted networks. Comedy Central (which lost Jon Stewart, John Oliver and Key and Peele) is down double digits, and so is BET. One outlier — surging VH1, up 14% — has thrived with Love and Hip-Hop and Basketball Wives, aimed at African-Americans, and now has more prime-time viewers than MTV. But all of Viacom's other adult networks are down among younger viewers.

The gainers. A few other major cable networks have seen steady audience gains, including HGTV (with a steady diet of house-flippers), up 13% this year; Hallmark Channel (up 9%), Investigation Discovery (up 11%) and WGN America (+44%). Common threads: Each has more original programming, at least some of it aimed at older, more loyal viewers. Smaller networks on the upswing include WEtv, Travel Channel, Sundance TV, GSN and Hallmark Movies and Mysteries.

Kids don't rule. Pint-sized viewers are among the most easily distracted by iPads, video games, Netflix and Amazon, which have dramatically increased their watch-anytime kids content. In prime time, Disney Channel is down 19%, falling from fifth to eighth place among cable networks. Nick at Nite is down 6%. (Nickelodeon and Cartoon Network, which share channel space with Nick at Nite and Adult Swim, respectively, are rated only for daytime hours).

Big-net woes. The general-entertainment networks are most like their broadcast counterparts, and while each has boosted its original series, as a group they are more dependent upon — and thus more hurt by — ratings for reruns of shows like The Big Bang Theory, NCIS and Law & Order. TBS, which also saw ratings drops for the NCAA basketball tournament, is down 10% this year, joining fellow decliners USA (-7%) and TNT (-5%). AMC is down a scant 3%, while FX is flat.