Marine Life & Conservation
Oceans Campaign Director – Greenpeace USA

John Hocevar is a trained marine biologist and an accomplished campaigner, explorer, and diver. John has helped win several major victories for marine conservation since becoming the director of Greenpeace’s oceans campaign in 2004.
Prior to joining Greenpeace, John was involved in several environmental projects including the Sea Turtle Nesting Project in Florida, Coral Cay Conservation in Belize, and as an environmental educator for Marine Science Under Sails in Florida. He is a graduate of the Green Corps organizing fellowship, a program dedicated to training the next generation of environmental leaders and previously worked at Corporate Accountability International. He is a co-founder and former executive director of Students for a Free Tibet.
I asked John if he remembered the defining moment when he knew conservation would play such a large part of his life.
John:
When I was about 11, I found copies of Rachel Carson’s “Silent Spring” and “The Sea Around Us” on a visit to my grandparents in the Upper Peninsula of Michigan. I’m not sure what made me pick them up, but those books changed my life. As for the ocean, it was love at first sight. I grew up in eastern Connecticut, so my first trip to the beach was Rocky Neck State Park.
Jeff:
What do you feel are the most important issues facing our oceans today?
John:
Unsustainable fishing, global warming, and ocean acidification are at the top of the list. We have come a long way in addressing pollution, but there are more plastic bags, bottles, and other throw away disposable items washing into the ocean than ever before.
Jeff:
For the past 40 years of my career as a wildlife filmmaker I have watched the oceans around me being polluted and over fished. Coral reefs have disappeared and other marine habitats ploughed up under the heavy weight of trawl nets. What realistic future do you see for our marine world?
John:
To some extent, it is still up to us, but our window of opportunity is closing quickly. The scientific predictions are extremely grim: one of the largest waves of species extinctions in the history of our planet, the end of coral reefs as functional ecosystems by the end of the century, the total disappearance of sea ice in the Arctic in the summer, collapse of most commercial fisheries, and what Dr. Jeremy Jackson has referred to as “the rise of slime” – surges in populations of jellyfish, algae, and bacteria.
Some of these changes are going to be extremely hard to prevent at this stage, but these forecasts all assume that current trends continue. The sooner we act to reduce carbon emissions, end overfishing, and create large scale parks which can help increase the resilience of marine populations, the more hopeful our future will be.
Jeff:
I personally find that the majority of people I meet have little or no comprehension of the depleted state of our seas. It’s difficult for the majority to become involved while at the same time struggling to make a living, raise a family and pay the bills. What do you feel is the best way of addressing this?
John:
We need to do a better job with showing people how the health of the oceans is connected to the fate of humanity. We live on a water planet; the oxygen in every second breath we take comes from phytoplankton in the ocean. Healthy fish populations feed a billion people and provide hundreds of thousands of jobs. Healthy mangrove forests and coral reefs help protect coastal communities from hurricanes and tsunamis. Tourism – beach vacations, diving, whale watching, and recreational fishing – is a multi-billion dollar industry.
Personal experience can be very powerful. The changes taking place in the ocean are invisible to people who don’t have a chance to look below the surface, so divers have a special responsibility to serve as ambassadors and share what we have seen – the good, the bad, and the ugly.
Jeff:
Greenpeace is a household name and I remember in my teenage years Greenpeace always being in the world news fighting for the protection of the great whales. There was a passion there we could get behind and support. I rarely hear any news these days unless of course I look for it. Having done that, it is obvious that Greenpeace is still a great force for world conservation. Do you think people know enough about what Greenpeace are doing now?
John:
Greenpeace is doing much more work than when we started back in the early seventies; we now have three ships operating year round and offices in 40 countries. On any given day, we are issuing press releases, providing technical advice to policy makers, supporting scientific research, exposing illegal activities, challenging governments, and confronting destructive corporations.
That said, we rarely reach the level of media saturation we did in our early years. The biggest change is in the media environment itself. Instead of just three channels in the US, for example, cable and satellite TV provides people with hundreds of options. News is tailored to niche audiences, so people tend to seek out what they want to hear. Newspapers are in serious decline, with many closing their doors and nearly all of them laying off their environmental and investigative reporters. We still regularly get covered by major news outlets, but the effect is not the same as it once was.
This has made social media much more important, with conservationists and ocean lovers playing a key role in sharing our news with friends and family.
Jeff:
Can you recall your most successful campaign and tell us why it worked?
John:
Some of my favourite victories took place before I started with Greenpeace: an end to incineration at sea, dumping nuclear waste, raw sewage, and industrial waste, and a ban on high seas drift nets, which killed tens of millions of birds, marine mammals, sharks, and other marine life each year. As with our work today, we achieved these victories by putting people at the scene of the crime and risking their lives to bring back stories and images that helped change the world.
In 2008, we put out our first report on the sustainability of the seafood sold at US supermarkets. All twenty we surveyed failed. In our latest edition, eighteen of those twenty retailers have now achieved passing marks. The most important part was just exposing the problem. Supermarkets competed with each other, either to get to the top of the ranking or at least to get off the bottom. Sometimes, as with Costco or Trader Joe’s, we made a more focused example out of the laggards, leading to improvements in those companies as well as in others who were watching nervously from the sidelines. And as is usually the case, it wasn’t just Greenpeace – other organizations were involved in this transition too, as were countless individuals who demanded change.
Jeff:
As commercial fisheries have nearly reached the end of profitability what and who do you feel is the biggest threat now?
John:
Our hope is that we can learn from past mistakes in time to prevent the collapse of commercial fisheries. Policy makers in many countries are getting better about managing fisheries, but they are much too slow in shifting to the precautionary, ecosystem-based approach we need. To make sure we not only stop the decline but rebuild fish populations, we need a network of fully protected marine reserves.
In the meantime, unsustainable fishing remains the biggest threat. We are suffering from a combination of overfishing, destructive fishing, and pirate fishing. We are making progress on overfishing and pirate fishing, but unfortunately a large portion of seafood is caught with gear that either damages the habitat which sustains the fish or kills large numbers of other creatures as bycatch.
Jeff:
Could you sum up for us why it is so important to preserve our oceans and tell us how to best support its conservation in our daily lives?
John:
As citizens of a water planet, we do not have the luxury of trashing our oceans without it coming back to haunt us. There is a very real cost – economic, cultural, and ecological – in going on with business as usual while we damage habitats, overfish stocks from the Arctic to the Southern Ocean, overheat the planet, acidify the ocean, and rely on unnecessary disposable plastic bags and water bottles.
Each of us can take small but important steps to help. Here are a few examples:
Switch to reusable shopping bags and water bottles, and energy efficient light bulbs and appliances.
If you drive, drive less – and make your next car a more fuel efficient model.
Seek out options to switch to renewable energy sources like wind and solar. Depending on where you are, it may be cost effective to install solar panels; you may also have the option to sign up with renewable energy providers.
At this stage, though, it is going to take more than the kind of changes we can make individually. We need to elect politicians who share our values, and hold them accountable, and we need to demand that corporations shift to more sustainable practices. We need new laws and regulations that reflect the scientific reality of our times.
That is no small feat, and getting there will require a little help from all of us. Join Greenpeace, or other environmental organizations that fit your values. Tell your elected officials what is important to you, and let your supermarkets and restaurants know that you want your seafood to be sustainable.
If you would like to know more about the work Greenpeace is doing, visit http://www.greenpeace.org
Blogs
The life of a Great White Shark

The great white shark, known scientifically as Carcharodon carcharias, embodies the apex predator of the ocean. This majestic creature’s life is a testament to survival, adaptability, and the intricate balance of the marine ecosystem.
Born in the waters off coastal regions, a great white shark begins its life as a pup within the safety of nurseries, typically found in warm, shallow waters. The pups, measuring around 5 feet in length at birth, are immediately equipped with an innate instinct for survival.
As they grow, great whites embark on a journey, venturing into deeper and cooler waters, often covering vast distances across the ocean. These apex predators are perfectly adapted hunters, relying on their impressive senses to detect prey. Their acute sense of smell, aided by specialized sensory organs known as ampullae of Lorenzini, helps detect the faintest traces of blood in the water from several miles away.
Feeding primarily on seals, sea lions, and other marine mammals, great whites are known for their powerful jaws lined with rows of razor-sharp teeth. Their hunting techniques often involve stealth, utilizing their streamlined bodies to approach prey from below and striking with incredible speed and force.
Despite their fearsome reputation, great whites play a crucial role in maintaining the health of marine ecosystems. As top predators, they help regulate the population of prey species, preventing overpopulation that could disrupt the balance of the food chain.
Reproduction among great white sharks is a slow and careful process. Females reach sexual maturity between 12 and 18 years of age, while males mature earlier, around 9 to 10 years old. Mating occurs through complex courtship rituals, with females giving birth to a small number of live pups after a gestation period of about 12 to 18 months.
However, the life of a great white shark is not without challenges. Human activities, including overfishing, pollution, and habitat destruction, pose significant threats to their population. Additionally, despite their formidable presence, great whites are vulnerable and face dangers from entanglement in fishing gear and accidental bycatch.
Despite these challenges, great white sharks continue to inspire awe and fascination among scientists and nature enthusiasts. Their presence in the ocean serves as a reminder of the delicate balance and interconnectedness of marine life, emphasizing the need for conservation efforts to protect these magnificent creatures for future generations to admire and study.
Want to learn more about sharks? Visit The Shark Trust website: www.sharktrust.org
Photos: avalon.red
Marine Life & Conservation
Book Review: Sea Mammals

Sea Mammals: The Past and Present Lives of Our Oceans’ Cornerstone Species by Annalisa Berta
This is a book packed with information about some of the most iconic and charismatic marine species. I have a particular soft spot for the pinnipeds, seals and sea lions, due to some incredible diving encounters over the years. So these were the pages I first turned to.
Once picked up this book is hard to put down. Polar Bears, Narwhal, Sea Otters, manatees, whales and dolphins adorn the pages with beautiful photographs and illustrations. Each turn of the page lures you in to discover more about a species you love, one you want to learn more about, some you have never heard of and even includes the details of fascinating animals that are sadly now extinct.
I think what I love most about this book is how it is organised. Rather than simply lump the animals into taxonomic groupings, they are put into chapters that tell you a story about them. Whether it is the story of their evolution, how they were discovered, their biology, behaviour or need for conservation. Once you have decided on an animal to delve deeper into, each species has its own story, as well as key information about size, diet, distribution, habitat and conservation status.
There is plenty to enjoy in this delightful book. Plenty to learn too. As the cold dark nights draw in, I can see myself delving into this book time and time again. This is a perfect gift for anyone that loves the ocean and its inhabitants. Or just treat yourself.
What the publisher says:
From the gregarious sea otter and playful dolphins to the sociable narwhal and iconic polar bear, sea mammals are a large, diverse, and increasingly precious group. In this book, Annalisa Berta, a leading expert on sea mammals and their evolution, presents an engaging and richly illustrated introduction to past and present species of these remarkable creatures, from the blue whale and the northern fur seal to the extinct giant sperm whale, aquatic sloth, and walking sea cow.
The book features more than 50 individual species profiles, themed chapters, stunning photographs, and specially commissioned paleo-illustrations of extinct species. It presents detailed accounts of these mammals’ evolutionary path, anatomy, behavior, habitats, and conservation. And because these are key species that complete many food chains and have the widest influence of all sea life, the book also offers insights into a broad variety of marine worlds today and in the future.
About the Author:
Annalisa Berta is professor emerita of biology at San Diego State University. A specialist in the anatomy and evolutionary biology of marine mammals, especially baleen whales, she formally described a skeleton of the early pinniped Enaliarctos. She is the author of Return to the Sea: The Life and Evolutionary Times of Marine Mammals and the editor of the award-winning Whales, Dolphins, and Porpoises: A Natural History and Species Guide.
Book Details
Publisher: Princeton University Press
Hardcover
Price: £25
ISBN: 9780691236643
Published: 26th September, 2023
Pages: 224
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