The silent killer: the disappearance of the world's estuaries

Our impact on the oceans over the last century has been greater than all previous centuries combined. We are quickly changing the oceans’ chemistry, temperature and biodiversity while at the same time, only just beginning to understand these changes’ implications. We know so little really; we are still learning about the oceans’ important role in our climate, atmosphere, and planet, still exploring their depths, and still discovering their inhabitants. And as we slowly build our knowledgebase, pollution, habitat destruction, global warming and overfishing are ravaging our seas – and all that dwell within.

Sharks sit at the forefront of this lethal combination of catastrophes, vulnerable to each of them. Sharks are being fished at the rate of 100,000,000 sharks per year, with many regional species up to 98% extinct. Bottom-dwelling sharks are chased by trawlers, whose fishing practices are so destructive, the muddy tell-tale signs of the underwater bulldozers demolishing the sea beds can be seen from satellites. And pelagic sharks frequently join the 43 million tons of bycatch caught by fisherman on long-lines and nets. No matter how they are caught, they are brought on board to have their fins sliced off - usually ending with the shark being thrown back into the water to die and rot.

At the same time sharks are being hunted for their fins at unsustainable rates, they are also struggling with the contamination of their environment. Not only have sharks absorbed the highly toxic methyl-mercury which compromises, amongst other things, their ability to reproduce successfully, but now scientists are also finding other strange neuro-toxins (linked to brain diseases like Parkinson’s and Alzheimer’s) in their flesh. Chemicals, whether dumped or run-off, enter the food chain and become concentrated as they make their way up the food chain. Even the tons and tons of plastics in our ocean – forming two “islands” twice the size of Texas in the Pacific and Indian oceans – are decomposing to a point that the polymer particles, which will take hundreds if not thousands of years to dissipate, are consumed. Some seawater has 7 times more plastic in it than zooplankton, and so this plastic poison also enters the food chain. All of these chemicals are literally poisoning the sharks – and anyone who dares to eat them.

As if not threatened enough, the struggling shark population is also battling with the destruction of habitat. Many sharks and rays rely upon estuaries as nurseries for their young. And sadly, estuaries around the world are under attack. Not only are the fragile ecosystems more susceptible to pollution and overfishing, they are often in areas considered prime real estate. Many estuaries have fallen victim to homes and businesses – either directly or due to the topographical changes urban development force.

The Zambezi Sharks of Southern Africa are one such casualty, for centuries, relying upon toxin-free estuaries to continue their cycle of life. While healthy in the 1960’s, the Zambezi Sharks’ population, also known as Bull Sharks, has plummeted – missing in large numbers from their usual haunts like Protea Banks. Many attribute this in great part to the disappearance of healthy estuaries. During the last 50 years, one by one, the sharks’ birthing places vanished, thanks to river damming, population explosions, and industrial pollution. In fact, reportedly only one estuary remains accessible, protected and healthy enough to serve as a nursery on the eastern coast of South Africa. Shark nets, targeted fishing, and destruction due to ignorant fear or a misplaced sense of competition, combined with an inability to rear healthy young have decimated the population.

Nearby Mozambique and its estuaries are thought to be the Zambezi Sharks’ salvation. So we decided to investigate this theory firsthand. On our recent trip, we visited countless estuaries and even dove in two. And the results, for this conservationist, were frightening.

Many of the estuaries we found were polluted from nearby towns and cities, serving as a makeshift waste facility for garbage, industrial waste and untreated sewage. Others had hotels built upon them, with what appeared to be little concern for their impact upon the fragile ecosystem. And more were dried up, with dead mangrove trees serving as the only indicator to the area’s previous vivacity, victims to changes in water flows that development and climate change inevitably bring about.

Imagine our excitement when we found a large estuary in Tofu that – from the surface – initially appeared to be healthy. We grabbed our gear and decided to see for ourselves… visions of immature sharks and rays dancing in my head.



The first thing that struck me as we approached was the lack of birds surrounding the area. Not a good sign. And then, as we walked to the site, I realized the luxury hotel next to us was dumping their waste directly into the water. It wasn’t until I saw the locals’ fish nets – installed with such intensity you can actually see them when flying above – did I finally acknowledge that perhaps we were mistaken.

We swam towards the mangroves knowing that their roots typically serve as homes for countless creatures. But all we found was a mossy, slime growing over sad strands of sea grass with long, gelatinous sea cucumbers and the spindly legs from sea stars woven in between. 90 minutes in the water and I could count the other life forms we encountered on one hand – a single crab, a small transparent shrimp, and a few silvery fish. Here was a huge bay that spanned as far as the eye could see and should have been bustling with life; instead, it was eerily silent. All that could be harvested from the estuary had been, and with the ecosystem completely disrupted and probably contaminated, what remained was the low level, and incredibly resilient members of the food chain – reproducing in large numbers due to the lack of balance.

For all practical purposes, this estuary, like so many others, was dead.

Resolute, we headed further north, finally escaping the populated areas and tourist destinations. After 6 hours of driving on non-existent roads, we happened upon an isolated estuary in Pomene Bay with a hotel perched aside the lovely bay, allowing us to spend five days observing the estuary – from above and under the water.

Our spirits soared as we heard stories of frogfish, sea horses, brindle bass, crabs and even dolphins. And over the next five days, our dives did not disappoint. Swimming through the beautifully healthy sea grass, we found a treasure trove. Anemones with huge, colorful popcorn shrimp, grasses and sponges entwined with several species of sea horses, black, yellow and orange frog fish lurking about looking for their next meal, beautiful juvenile angelfish displaying the vibrant patterns of youth, sand dollars hairy and purple shuffling on the bottom, and countless varieties of flounders, nudibranchs, scorpionfish, eels, and pipe fish this muck diving veteran had never seen before. We also met several scientists who were busy discovering new species – or species thousands of miles away from their reported home.


What a special place. It was like diving in the macro-heaven Sulawesi, Indonesia – without the garbage.

Our frequent boat trips through the estuary delivered topside sightings of flamingos, humpback dolphins, schools of hunting, large game fish, and even a turtle. Yes, this was a healthy estuary – one that was serving as a nursery and protected area for many species, including sharks no doubt. And one desperately in need of protection.



You see, it wasn’t long before our rose colored glasses wore off and we began noticing the locals that descended upon the estuary in full force day after day at low tide. Dozens of women filling bags and bags of razor clams. Fisherman dragging tiny mesh nets through the fragile grass catching fish, eels and everything else in their path, later throwing the precious bycatch not yet realizing its commercial value, like the sea horses, carelessly aside on the beach to die. Crowds of men with long poles who would stab at the water with as much caution as if they were jack hammering a pothole. I couldn’t believe my eyes. Day after day, this place was being assaulted. How much longer could it possibly last?



This place, like so many others, is falling victim to our collective ignorance and greed, while we blindly ignore the tremendous consequences upon things needed for our own basic survival. Remove the fish, remove the sharks, kill the fragile ecosystem and we jeopardize far more than a single estuary. We jeopardize the already strained oceans, our life source. And what’s worse, this is happening all over the world. Estuaries are threatened with extinction.

Perhaps there is hope for this estuary. The resort manager, Joe, a passionate lover of the oceans, recently convinced Maritima (the governmental agency responsible for protecting their coasts) to come and see the estuary for themselves. Not only did Maritima protect the area in front of the resort - the artificial reef – from gill-netters and agree to assess the impact in three months, but they are considering making the entire estuary a marine protected area. Of course, enforcement is always a challenge – I joined Joe in chasing away fisherman netting where they were not allowed. We also filmed what we saw – both the good and the bad – and are providing it to the government, to further the cause, writing letters to the ministry as well.

Our population is already at levels that are not sustainable from a resource perspective on this planet – so it isn’t surprising that in a country where 80% of the people live below the poverty level, it is a mad rush to take whatever they can. Even less excusable is the fact that more wealthy countries seize this as an opportunity to irresponsibly ravage these resources as well, destroying everything including estuaries in their path. The oceans are both our dumping grounds and our endless supply of life irregardless of our stewardship. It is up to those of us who care and can see the big picture, to stop the destruction. Or minimally, fight the good fight and be very noisy while it happens before our very eyes. The sharks, the sea horses, and even our fellow human beings, depend upon it.

Threatening those that threaten: Sharkfinning in Mozambique

Southern Africa has some of the richest shark waters in the world – which is part of the reason I find myself, a shark conservationist from Chicago, USA, drawn here. Over 210 species live in the nearby waters, more than 60 of which can only be found here.

However, like many other places around the globe, Southern Africa's sharks are vanishing before our eyes at alarming rates. Shark finners, motivated by the out of control demand for shark fin, have locked their target and are ravaging one of Africa’s most precious resources. Leaving behind a wake of disaster for the locals – and the rest of the world - who will suffer considerably when these waters are depleted of sharks.

I learned this first-hand on a recent trip to Mozambique.

Offshore, it is estimated that the area surrounding Mozambique has the highest concentration of long-line fishing vessels in the world. Over 200 are targeting shark for their fins. Any one of these vessels is capable of catching more than 100 tons of sharks per trip, quickly offloading to factory ships offshore only to fin again. In June, an illegal Namibian ship was seized with 43 tons of sharks, an estimated value of US$5 million, onboard the unlicensed ship.


Inshore, sharks face a similar fate from artesianal fisherman.

With 80% of Mozambicans living below the poverty level, it isn’t surprising that sharkfinning is running rampant. Fins from a single shark can fetch up to US$120, a few months’ income. Consider a small boat can land as many as 1,000 sharks a year and you have the recipe for environmental disaster.

The word is out. Shark fins mean big money and fishermen, desperate to feed their families, are heeding the call.


Before long-line fisheries began in early 2000, anecdotal reports indicate the shores surrounding Mozambique were rich with sharks and rays. These days, it is a very different story, with our own dives consisting of a rare shark or ray sighting only a handful of times. Unfortunately, the lack of infrastructure available for coastal monitoring and enforcement leaves Mozambique, like so many other countries, horribly exposed to illegal, unreported and unregulated fishing. The government estimates that last year, the cost of this fishing to Mozambique was almost US$40 million.

However, a public groundswell is forming. Those passionate about sharks have formed a group called Eyes on the Horizon. A brilliant concept and one long overdue, members serve as the “eyes and ears” for the resource-strapped government. It was their Executive Director, Simon Pearce, who told us about Pomene.

When we arrived in Pomene, we recalled Simon telling us the shark finners were chased out just three weeks prior. A group of migrants who systematically move up the coast of Mozambique, they relocate when a local shark population is depleted – or when a local community becomes fed up with the impact the shark fisherman have on their livelihood – including the fish and tourists that they rely upon. Fishing accounts for over 50% of Mozambican’s incomes so it wasn’t long before local fishermen realized that when the apex predators like sharks are removed, the other fish beneath them on the food chain disappear as well.

Pulling into town, we spied the telltale sign of shark fishing: shark jaws hanging in the roadside curio huts. Upon closer inspection, the fresh, pink flesh on the jaws indicated these were recently caught. There were over a dozen jaws - bulls, tigers, grey reefs - some from sizable animals. When I began asking about the jaws, everyone surrounded me eager to make a sale. But, as more and more questions arose, suddenly everyone’s English was forgotten.


It was obvious the shark fishermen were still nearby.

Searching for shark fisherman is a complex and can also be a dangerous game. Especially in a third world country rife with poverty and crime where English is not readily spoken. You can’t simply go in and start asking questions expecting to be dropped on the deck of a long-liner with a gracious welcome, nor can you intentionally jeopardize the excessive income of a fisherman surrounded by poverty - without putting yourself into immediate jeopardy. Given the money involved, shark fishing is not unlike drug trafficking rife with suspicion, murder and corruption. Many shark finners operate behind veils of secrecy and are known to be ruthless - often times shooting at those that try to stop them. Some of my conservationist friends know this firsthand having found themselves at the business end of machine guns - which I am told are easily come by in Mozambique.

So, instead, you must build rapport and trust with a few locals. You must ask innocent, uninformed questions and remain completely non-judgmental about the responses. You must invest time and learn what motivates the community. You must earn the respect of local conservationists by proving you are passionate and just want to help, easing their suspicions. You must consider everyone an asset extracting bits of information from all you meet, fashioning it together like a complex jigsaw puzzle whose pieces are spread out over miles of terrain. And, you must get lucky. Which, in this case, we did.

After a week building rapport, we earned the trust of a resort owner and his local staff who knew plenty about the shark fisherman – and were willing to serve as our translators and transportation. And we gathered enough intelligence to know the shark fisherman were indeed migrants disliked by the locals, who were supplied their fishing gear by the businessmen that purchased their fins and were actively still fishing five kilometers up the coast in a village whose chief was notoriously corrupt.

That was enough to pull together an expedition to locate the shark finners.

It wasn’t long before we found their camp… and their long-lines. And it wasn’t long before they found us; our boat was identified immediately. These shark fisherman were extremely nervous already – as they had just been chased out of their previous camp. They weren’t about to let it happen again.

A few local fisherman gave their lines up, pointing us in the direction of two buoys, about 50 meters apart and equidistant from shore. Innocent enough, the buoys floated at the surface. If you didn’t know better, you would never have guessed what was sunken below.


The boat full of shark fisherman saw us approach their buoys and immediately went back to their camp for reinforcement. We took advantage of the gap and slipped into the water. But we were told to hurry – it wouldn’t be long before our problems multiplied. So We descended to see what lay below.

What we found was two sets of sunken lines (called bottom lines) one tied to each buoy line near the sandy bottom. A few meters later, we found the first attached long-line with a “j” hook, thick and corroded, ten meters apart from the next hook, baited with what appeared to be eel (later we found they were getting bait from the protected estuary nearby and had been chased away countless times). The fishing lines were heavy ropes with attached metal lines and swivels to ensure a captured shark wouldn’t be able to bite through the line or break free.

The lines extended past the sand, right over the reef, and my heart sank as I recalled all the other long ropes I had seen laying on the fragile coral at the other dive sites we had visited. The fisherman had been there too.


In the short time we dove the lines, we found a huge remora with a hook through its eye socket, bleeding profusely, obviously unintended bycatch. The remora’s sad eyes plead with us to save it though it seemed to have accepted its fate, lying in an unnatural position presumably overcome by agony. We tried desperately to free it, but to no avail. My mask grew blurry and I realized I was shedding tears for what I knew was happening here – and on the rest of the hooks throughout the world that I couldn’t see.


When we ascended, the resort owner told us we must go in a tone that conveyed a clear sense of urgency. Still in shock, we gathered our gear together and prepared for a speedy journey home. As we neared the beach to make our way home, the shark fisherman began pouring out from the bluffs, some with machetes in their hands. There was much shouting and hand waving as they accused us of cutting their lines and dared us to land the boat on shore. And, even though I did not speak Portuguese, there was no mistaking the tone, intensity and visual cues. These fisherman were ready for battle.

The resort owner suddenly realized the guide had a shirt on from the resort and whisked us away before we could be identified – fearful of the ramifications. The night watchmen were put on full alert for days following the incident, as he knew exactly what we were dealing with. We were miles away from any sort of enforcement or support, let alone infrastructure. Laws didn’t apply in places like this – and there was no place to hide.


I was so caught up, it wasn’t until days later that I realized just how much danger we were in. Caught up in passion, I lost all sense of reason having finally found myself with the ability to take on those killing the sharks face to face, and I was willing to do whatever it took. Thankfully, my mates, having grown up in Africa, prudently recommended we return when we have more support and options.

In the meantime, we have turned over the finners’ location to the governmental agency, Maritima, and to Eyes on the Horizon. I am hopeful they will do whatever they can – including the government whom boldly showed commitment to the cause by recently deciding to turn that seized Namibian shark fishing vessel into a patrol boat.

And, we are determined to return to Mozambique to get involved in grass roots efforts, educate local fisherman on other sustainable options, work with Eyes on the Horizon, and, in some small way, contribute towards the establishment of a structure that the rest of the world can follow. We need to send a message that shark finning cannot and should not be tolerated in any country – nor can it be sustainably beneficial, either economically or environmentally.

We are all connected to one another, and to the sharks, who keep our oceans healthy. Countries around the world, like Mozambique, who are struggling with basic socio-economic issues, desperately need everyone’s help to save the last remaining sharks. I just hope we aren’t too late.