The Smithsonian Network is no stranger to the documentary-on-DVD game, and most of their efforts fall under the categories of "history" or "nature". Down Under the Sea is no exception: this boxed set pairs two like-minded underwater documentaries from 2006, The Big Blue and Secrets of the Great Barrier Reef. Both focus on life above and below the water's surface near Australia. Both feature plenty of narration by (and interviews with) experienced fisherman and explorers. Both, obviously, are packed with plenty of beautiful blue imagery. Yet, aside from these basic elements, they're really all not that similar.

The Big Blue (93 minutes), despite having plenty of underwater footage at times, is a decidedly more dry affair. This well-meaning but uneven documentary takes us to the southern end of Australia's waters, a common feeding ground for the elusive Blue Whale. During much of the journey, we join a group of fisherman eager to see the scarce species in its natural habitat...and on several occasions, we get to see a few amazing clips of these massive whales above and below the surface. Unfortunately, the action is occasionally interrupted to focus on various birds and seals struggling to survive in the region. Some may view these detours as welcome breaks...but this collection is titled "Down Under the Sea", so they can't help but stick out like a sore thumb.

Secrets of the Great Barrier Reef (47 minutes), on the other hand, delivers a more visually focused adventure that does a great job of staying underwater. This documentary explores portions of Australia's famous reef of the same name; specifically, during a period in November when mating rituals and beautiful sights are commonplace. It's a visually arresting film from start to finish, and will easily hold the attention of young and old viewers alike. Although The Big Blue definitely wins in the quantity department (due, in no small part, to the size of its subject), Secrets of the Great Barrier Reef is tighter and more involving from start to finish.

Smithsonian's DVD release is unfortunately a bit thin, however: the technical presentation is slightly flawed and bonus features are minimal, which ultimately makes this release more of a rental candidate than a blind buy. Let's take a closer look, shall we?

Presented in the original 1.78:1 aspect ratio, Down Under the Sea is not anamorphic; doubly disappointing, since both films begin with a "Smithsonian Channel HD" logo and a few pre-menu ads are presented in 16x9. Aside from this glaring error, though, it's tough to complain: many of the underwater shots---especially in Secrets of the Great Barrier Reef---are crisp and vivid. The natural color palettes are also preserved nicely, and even the darkest scenes tend to avoid murkiness and digital noise. Overall, this is a decent presentation---but with a lack of anamorphic enhancement, the score can't help but look a bit low on paper.

In the audio department, Down Under the Sea is a bit more consistent. The films are presented in your choice of Dolby Digital 5.1 Surround or 2.0 Stereo, and both get the job done: music, dialogue and narration rarely fight for attention, while rear channels are lightly used to create mild ambiance. Optional English SDH captions are provided during the main features.

With roughly three hours of total content and a variety of undersea subjects to its name, Down Under the Sea boasts a fairly solid collection of material that documentary fans should enjoy. Still, a number of nitpicks keep this release from earning higher marks; specifically, the uneven focus of The Big Blue and the non-anamorphic video presentation of everything here. Although priced to sell, this two-disc set makes a more appropriate weekend rental than a part of your permanent collection. Rent It.