After sea turtle hatchlings emerge from their nests, they vanish into the sea. Until recently, their journey was largely shrouded in mystery. Now, as technology advances, researchers are beginning to understand where turtles go during their so-called “lost years.”

Each year, thousands of tourists interact with the tame southern stingrays that congregate in the shallow waters of Grand Cayman’s North Sound. Famous marine artist and scientist Dr. Guy Harvey has assembled a research team to study what impact the ecotourism might have on the wild fish.

The unique oceanographic conditions of the eastern tropical Pacific make the area one of the best spots in the world for big game anglers to hook billfish. But intense pressures from commercial fishing operations have taken their toll on the numbers of sailfish and marlin in the region. Researchers are studying the animals to provide the data necessary to protect the fish populations from further decline.

Most people are familiar with the pretty tropical fish found in aquariums, but few realize that some of these animals are capable of changing sex. Discover the unique ways of how some fish species do this and why they likely evolved this way.

Until recently there was scientific consensus that sponges were the first animals to branch off the “Animal Tree of Life,” a kind of family tree for all living and extinct animals on earth. But recent DNA research has cast doubt on that theory, with some scientists suggesting that ctenophores, also known as comb jellies, are an older lineage.

Every winter, hundreds of manatees aggregate at Crystal River, Florida, attracted by the warmer, spring-fed clear waters. This sanctuary is also a treasure for scientists, who take advantage of these manatee gatherings to study them. From decades of visual ID studies to the most cutting-edge DNA research, experts hope that science will help conserve this beloved marine mammal.

In the remote Pacific, the islands of Maug rise out of the sea. Formed by an ancient volcano, shallow hydrothermal vents are found close to coral reefs inside the submerged caldera. These vents emit levels of CO2 that can be expected in the world’s oceans by the end of the century, making these waters a natural laboratory for scientists studying the impacts of ocean acidification on coral reefs. Co-produced with Open Boat Films.

The Blue Heron Bridge in Riviera Beach, Florida, is known as one of the best shore dives in the United States. What appears as an unlikely dive site at first is home to a rich variety of marine life, ranging from tiny nudibranchs to manta rays. Underwater photographers are documenting what lives beneath the bridge, and a scientist is studying how two species of octopus co-exist there.

Scientists work with the private sector to develop sustainable offshore aquaculture.

Putrid mats of blue green algae are wreaking havoc on Florida’s shorelines. Scientists think water pollution is to blame, and if something isn’t done about it there could be irreparable damage to the environment, the local economy and people’s health.

For millennia, the exchange of CO2 between the oceans and atmosphere has been in balance. Now, with more anthropogenic carbon dioxide in the atmosphere, the oceans are taking up more CO2 as well. This additional CO2 is negatively impacting sensitive ecosystems, making scientists worry how these changes will affect the way carbon is cycled through the seas.

Mexico’s remote Revillagigedo Archipelago is a hotspot for oceanic mantas. Scientists use photo ID techniques and acoustic tags to study these mysterious fish. They are also researching if the filter-feeding rays are impacted negatively by microplastics – tiny pieces of toxic trash that float in the ocean.

Dr. Denise Herzing has dedicated her career to studying wild Atlantic spotted dolphins in the Bahamas. She researches the animals’ social structure, behaviors and communication. Now modern technology is making it possible to correlate the dolphins’ sounds and behavior, bringing experts closer to decoding dolphin communication.

On a shipwreck near Key West lives a tiny potential new threat. Researchers want to know where this new species came from, and whether its sudden appearance spells disaster for the delicate coral reef ecosystem in the Florida Keys.

While American crocodiles are recovering in parts of their range, their future looks bleak in Jamaica. Habitat loss and poaching have led to a drastic decline in the population. Dedicated experts are working to save the species through research, education, and conservation initiatives.

Flats fishing is popular with recreational anglers in the Caribbean and the Florida Keys. But until recently, little was known about tarpon, bonefish and permit – the species most coveted by sports fishermen. Now scientists are studying the fish to better understand their movements, habitat, and spawning behaviors.

California’s north-central coast is famous for its natural splendor. Only fifty miles northwest of San Francisco’s Golden Gate Bridge lies the Cordell Bank, a magical underwater island few people have ever heard of. Protected inside a National Marine Sanctuary, this oasis is an ecological hot spot for marine life - attracting birds, sea turtles and marine mammals from thousands of miles away.

Harmful algal blooms come in many forms, from toxic outbreaks impacting the health of animals and humans, to non-toxic but expansive sargassum mats devastating local economies and tourism. Scientists are working to understand what causes these blooms, how they impact us, and how we can stop them.

Stony Coral Tissue Loss Disease is devastating Florida’s fragile coral reef ecosystem. But all hope is not lost. Dedicated scientists are working hard to find the cause of the disease, treat the ill and restore these cities of the sea to their former glory.

Each winter, a population of humpback whales migrates to its breeding grounds in the Hawaiian Islands. It is here that male humpbacks perform their elaborate and haunting song. Experts are studying the purpose of this song and what it might tell them about the animals’ overall fitness.

Scientists explore mysterious blue holes scattered throughout the Gulf of Mexico.

Ten years after the Deepwater Horizon oil rig disaster, scientists study its devastating impacts on the Gulf of Mexico and use lessons learned to prepare for the next big spill.

Scientists study the adorable Humboldt penguins that nest along Peru’s desert coastline.

Experts study what makes American Samoa’s coral reefs more resilient than reefs elsewhere.

Shore-based, catch and release shark fishing is a popular past time in Florida. But is it having a negative impact on sensitive shark populations? Scientists have teamed up with anglers to study the survival rates of the fish and conduct outreach on best practices.

Along scenic coastlines in the South, waves of mesmerizing green and golden grass stretch to the horizon. This is the salt marsh - a part liquid, part solid landscape that is teeming with life. How do scientists study the salt marsh? And how resilient is it to climate change?

The deep-sea submersible Alvin has brought explorers to extraordinary places for more than 50 years. Now, as Alvin is poised to continue its revolutionary scientific work, a new set of upgrades will take it deeper than ever before.

Tarpon and snook are two of Florida's most iconic game fish. Both species rely on mangrove creeks and ponds when they are juveniles. With half of the state's mangroves lost to development, scientists employ creative solutions to restore and reconnect some of these important habitats to secure the future of the fisheries.

The humpback whale population that migrates between Hawaii and Alaska is considered a conservation success story. When sightings of the animals suddenly dropped, people became concerned. Scientists in both locations are trying to understand what happened to the whales and why.

How does the body size and overall health of humpback whales change across their migratory cycle? A team of researchers studying the animals, which spend part of the year feeding in Alaska and a few months fasting while in their Hawaiian breeding grounds, is making remarkable discoveries.

Kelp forests have played an essential role in the Puget Sound ecosystem for thousands of years. Today, kelp is in decline. Experts work against time to conserve and restore them.

Florida's iconic sea cows are dying in record numbers. Years of declining seagrass beds have eliminated one of the gentle giants' primary food sources. Now wildlife managers have taken the unprecedented step of feeding the animals, while scientists are in a race against time to restore the lost seagrass.