“Deadliest Catch” (9 p.m., Discovery Channel): The fifth season of “Deadliest

“Deadliest Catch” (9 p.m., Discovery Channel): The fifth season of “Deadliest Catch” is being heralded as more deadly than ever. But does that mean it’s more deadly for the boat crews — or for the crabs? The crew faces storms as it searches for a ship that sank.

“90210” (9 p.m., CW): Donna Martin alert! Tori Spelling reprises the popular character on “90210,” where she pays a surprise visit to Kelly and Silver. Fine, but where’s David?