I began my scientific career as a student in Jamaica, where we noted the scarcity of fish due to extreme overfishing, but paid more attention to the bountiful, colorful corals. By the mid-1980s, a few years into my first job, the corals were also gone.
Fast forward 30 years, and I am pummeled daily by news of dissolving baby oysters, collapsing fisheries, growing dead zones, and mounting tons of plastic, not to speak of fresh images of seabirds once again soaked in oil.
The ocean was once considered too vast for us to harm. But today, all evidence suggests that ocean habitats throughout the world are endangered by the quadruple threats of pollution, overfishing, habitat destruction, and carbon emissions.
Yet I am still optimistic that we can reverse our course, put in the work to rebuild and protect ocean habitats, and improve our ocean's health, for our own good and that of marine life.
Where does my ocean optimism come from?
Two years ago, I spent a month diving in the Southern Line Islands. These reefs in the middle of the Pacific Ocean didn't get the doomsday message. Vibrant coral carpets the seafloor, and turtles and manta rays and groupers roam. The reefs seem to be surviving, indeed thriving, even though they are bathed in the warmer and more acidic waters caused by the burning of fossil fuels. What is their secret? It's quite simple: They are resilient thanks to the abundance of fish and the lack of pollution coming from the land, a pattern seen around the world.
Sharks represent another cause for hope despite catastrophic overfishing caused by the demand for shark fins used in shark-fin soup. Why? There is growing public disgust with the images of still-living, finless sharks dumped overboard to slowly bleed to death. For governments, it is also a question of dollars and cents, or dollars and sense, if you will. In Palau, a country that depends critically on underwater tourism, studies showed that a dead shark is worth $108 -- but a single live shark is worth $1.9 million over the course of its lifetime.
As a result, governments and companies around the world are taking action to protect sharks. Around 100 countries have banned shark fishing, finning, or the sale of fins, and 26 airlines refuse to transport shark fins. The Chinese government has set an example for its citizens by no longer serving shark-fin soup at official banquets.
Early evidence suggests that these efforts are working. A 2014 survey from WildAid, an anti-wildlife trafficking organization, found that 85 percent of people in four Chinese cities said they had given up shark-fin soup within the last three years -- and that, in only two years, shark-fin sales had declined by 50-70 percent and shark-fin prices dropped by 50 percent.
Meanwhile, sharks seem to be getting over their "bloodthirsty" reputation. On Cape Cod, where Jaws was filmed more than 40 years ago, shark tourism is booming. A great white named Mary Lee cruising the Jersey Shore has more than 74,000 followers on Twitter. And who would have thought that a shark could upstage Katy Perry at the Super Bowl?
Want some more reasons to be optimistic? Ospreys, pelicans and bald eagles now thrive on our coasts, saved from the fate of the dodo because we banned DDT in 1972. Ditto the snowy egret, whose lovely feathers once adorned so many ladies' hats. They were saved by a campaign similar to the one that aims to keep sharks off the menu today. Many humpback-whale populations have come back from the brink, and sea turtles are returning to some beaches. Sea otters, once decimated by hunting, now support a huge tourist economy in Monterey Bay. Thanks to replanting, breeding and clean-up efforts, oysters are returning in the Chesapeake Bay. This year, the status of U.S. fish stocks showed management working to an unprecedented degree, says the National Atmospheric and Oceanic Administration. Around the world, governments are taking the care of their ocean resources more seriously.
Now please understand: In many parts of the world, the ocean remains sick, indeed. These local efforts need to be drastically scaled up. But it is the height of folly not to recognize, celebrate, and emulate our past successes.
What about climate change, the ultimate threat? No credible ocean scientist will tell you that local efforts will forever protect the ocean against continuing emissions of carbon dioxide. But locally managing fishing and pollution is not rocket science, and it buys us valuable time while we figure out how to wean ourselves off the carbon economy.
Conservation and media organizations are increasingly aware that ever more vivid documentation of huge problems without solutions leads to apathy, not action; you can't scare people into caring. So if you too have had it with doom and gloom, search for #OceanOptimism on Twitter for inspiration on how you can work locally to restore ocean habitats. Every day, new posts appear thanks to a movement launched on World Oceans Day in June 2014. Read these stories, and think about how fast our world changes. Ocean conservation and restoration are no different from other social movements: they too can go from seeming impossible to becoming inevitable with the efforts of individuals and communities.
This post is part of a series produced by The Huffington Post in partnership with Ocean Unite, an initiative to unite and activate powerful voices for ocean-conservation action. The series is being produced to coincide with World Oceans Day (June 8), as part of HuffPost's "What's Working" initiative, putting a spotlight on initiatives around the world that are solutions oriented. To read all the posts in the series, read here.