I think midsummer, pre-election, is a good time to examine a few major trends we’re seeing in ocean and river cruising, though I’m going to concentrate on the upper ends of these markets.

The cruise market is growing at about 4% a year, despite some nasty weather, Zika concerns and the growing fear of terrorism. CLIA predicts that more than 24.2 million people will take an ocean cruise this year. The biggest one-year projected gains have been in Asia, which is up 24%, and Australia, up 14%.

As recently as 2010, China’s cruise market was still on the drawing board. Cruises in China tend to be sold as complete packages by middlemen who normally charter an entire ship or large portions of an available sailing.

Carnival Cruise Line will have six ships in China this year, and Princess has a new Chinese market subsidiary. Royal Caribbean has taken the biggest risk, placing the 4,905-guest Quantum of the Seas there, and Norwegian Cruise Line is building a ship specifically for the Chinese market.

The big question is how appropriate are these “Chinese-designed” cruises for the American traveler? To what extent will Mr. and Mrs. Mainstreet feel truly comfortable on a cruise designed for Chinese tourists?

In the meantime, I’m betting that luxury adventure cruising is poised to become this year’s industry growth leader. A 2013 report from the World Tourism Organization placed the value of the adventure market at more than $265 billion. If this is accurate, it means that expedition cruising has enjoyed a 24-month growth rate of something like 195%, a staggering figure. Get ready for the advent of the adventure yacht boom. Here are some of the key players in this growth:

Lindblad Expeditions-National Geographic went public last year and promptly ordered two 100-passenger vessels for U.S. coastal voyages. It also bought Via Australis and will place several of its ships in the Galapagos after major refurbishments.

Lindblad, which invented nonscientific expeditions to Antarctica 50 years ago, operates six vessels carrying between 28 and 148 passengers. Instead of casinos and lounge acts, its cruises are likely to include top-tier naturalists, undersea experts, historians and expedition leaders, plus a National Geographic photo instructor or photographer to ensure Pinterest-perfect photos. Lindblad has started including organic food sourcing whenever possible. But, alas, there is no bingo.

Crystal Cruises will be taking delivery of a polar-class, 200-passenger megayacht, the Crystal Endeavor, in August 2018. At 600 feet long and 25,000 gross tons, it will be the world’s “largest and most spacious” megayacht, capable of handling travel within polar regions. In its first season, it will follow migrating whales from the Arctic to Antarctica.

To offer guests the ability to truly explore some of the world’s most remote destinations, the Endeavor will carry equipment not previously seen on a luxury adventure vessel. These will include two helicopters to take guests for flyovers, two seven-person submarines for deep-sea dives to view underwater glaciers and coral reefs, an all-terrain vehicle, a fleet of personal watercraft and even a recompression chamber for serious scuba divers.

Silversea has been credited with leading the growth trajectory of luxury adventure cruising. It began with the Silver Explorer in 2007, and the line is now converting a five-star luxury ship, the 296-guest Silver Cloud, into a polar-class vessel. The goal is to offer guests a chance to explore some of the more extreme destinations on Earth with a one-to-one staff ratio and five restaurants onboard.

In 2017, the line will take delivery of the 596-guest Silver Muse, which is expected to have the industry’s best staff-to-guest ratio. In many ways, the line is redefining the way luxury travelers explore remote corners of the globe, with the assurance that a well-stocked wine cellar awaits them when they return to their ship.

Seabourn is approaching five-star adventure cruising with a different emphasis, having designed itineraries that highlight spots in the world high on every adventure traveler’s list, including Patagonia, Antarctica and the Amazon. Seabourn is getting two new ships: the Encore later this year and the Ovation in 2018. With these newbuilds, Seabourn has decided to up the passenger count from 450 on its current Odyssey class ships to 604.

Scenic, the upstart Australian luxury tour and cruise company, is launching what it calls “the world’s first discovery yacht” in August 2018. It will sail to the Mediterranean, Antarctica and the Arctic, which you would expect of a self-described “six-star” vessel whose smallest suites have a butler and a veranda and measure 345 square feet. Even more spacious will be a two-bedroom penthouse suite, at 1,775 square feet.

While it might sound like the routes through the ice in Antarctica will get rather crowded in the next several years, Scenic is also placing its “most technologically advanced yacht in the world” closer to home, with a series of cruises in the Americas that include two 14-day circumnavigations of Cuba from Miami.

River cruising on the Mekong River is increasingly seen as a sexy alternative to traditional river cruising.

The Amazon has the world’s greatest biodiversity, but the Mekong River is second, with more than 1,300 known species of fish along its 3,050-mile path through Southeast Asia. The Mekong is the next hot destination, and travelers will discover that the vessels deployed on this route are built locally and represent the highest levels of shipbuilding craft, with dark wood floors and original furnishing. AmaWaterways, Abercrombie & Kent and Aqua Expeditions are leaders in this market.

It has been said that if you want to vacation in style with good food, just figure out where the French are going these days. But Americans have another option. They can sail with the French to all seven continents on the laid-back, luxury French line Ponant.

The original Le Ponant still sails as a 64-guest cruise ship. But its four sisters, Le Boreal, Le Soleal, L’Austral and Le Lyrial, now form the bulk of the fleet. Ranging from 224 to 264 guests, they feature not only French style but ice-hardened hulls for polar exploration. Each of the vessels has several lounges, a theater, library and a pool. Ponant’s ships are heavily utilized by Tauck Tours’ escorted sailing itineraries.

In the meantime, river vessels have evolved to embrace luxury. There was a time when a ship sailing any of Europe’s major rivers was filled with 120-square-foot cabins, close to the mandated size of a prison cell in many states. But things are changing.

Since river ships must be less than 443 feet long to fit through locks and there are strict limitations on height because of low bridges, cruise lines have to get creative with cabin design.

Uniworld has a simple little switch that raises window glass to form an open-air solarium. Scenic Cruises has a “sun lounge,” a balcony surrounded by glass that can be easily opened to the river.

AmaWaterways has one-upped its competitors by designing twin balcony suites consisting of both a French balcony and a true balcony.

But perhaps the smartest and simplest innovation is that of Avalon’s panoramic suites, which constitute a majority of its cabins. Avalon has managed to turn the beds around so they face the window. A glass wall opens so guests get a sense of floating on the river from the comfort of their beds.

Seabourn added Penthouse Spa Suites on the Quest, and they will be added to the line’s other ships this year. Just one deck above the ship’s spa facilities, each of the suites is a bedroom with a sitting area, and they are decorated to match the spa below. They will feature specially designed, oversize showers, spa bath amenities and a soundtrack of soothing spa-influenced music.

Crystal is taking a different approach to health and wellness. The Serenity came out of drydock with 70 remodeled cabins that are cleaned using hypoallergenic products. Each cabin is also equipped with special air filters. The hotel industry has flirted with this “cleaned more proactively than our regular rooms” concept and decided to abandon it. It remains to be seen if Crystal will find an audience for environmentally treated cabins.