A sobering global assessment reveals that half of all the world’s vital mangrove forest ecosystems are at risk of collapse.

By Stuart Butler

A tangled mass of semi-exposed roots and tightly bunched trees rise up out of the naturally dark waters of a mangrove forest. Fish navigate through the maze doing their best to avoid the glare of hungry birds watching and waiting in the trees above. Mud skippers, looking like a cross between a fish and a salamander, haul themselves out onto damp muddy banks. A troop of monkeys causes chaos as it smashes through the canopy, and below, half hidden by the shade, a huge crocodile waits for its moment.

The world’s mangrove forests, which occur on tropical coastlines the world over, are one of the most diverse, important and resource-rich habitats on Earth. Mangrove swamps are home to a bizarre cast of animals, including some rather unexpected species such as man-eating tigers in the Sundarbans (the world’s largest mangrove swamp) of Bangladesh and India, whale sharks, proboscis monkeys with their massive noses, fishing cats and prehistoric-looking horseshoe crabs.

Mangroves are also key fish nurseries without which fish stocks would likely diminish massively. It’s even been estimated that 80 per cent of the global fish catch relies on mangrove forests either directly or indirectly. They also help human-kind in other ways. Mangrove swamps are vitally important carbon sinks, storing four times more carbon than any other type of tropical forest; they act as natural – and highly effective – protection against flooding and erosion and they help improve and maintain local water quality. So, it’s clear that a world without mangrove forests would be a sadly diminished planet.

But, we might have to start adapting to a world without mangroves if a recent assessment conducted by the International Union for Conservation of Nature (IUCN) Red List of Ecosystems is correct. The report, which makes sobering reading, says that more than half of the world’s mangrove ecosystems are at risk of collapse (classed as either Vulnerable, Endangered, or Critically Endangered) by the year 2050.

Of this, nearly 20 per cent of the assessed mangroves are considered at severe risk of collapse with the mangroves of southern India, Sri Lanka and the Maldives being the most endangered. In other countries the damage has already been done with Thailand thought to have already lost 84 per cent of its mangroves.

Mangroves are threatened from multiple angles. Deforestation, development, pollution, and dam construction, are all big causes of mangrove forest destruction. However, two of the industries most destructive of mangrove forests are shrimp farming and coastal tourism.

Another, growing, risk to these ecosystems is from sea-level rise and the increased frequency of severe storms associated with climate change. The assessment team concluded that climate change is thought to threaten one-third of the assessed mangrove ecosystems. 

‘Mangrove ecosystems are exceptional in their ability to provide essential services to people, including coastal disaster risk reduction, carbon storage and sequestration, and support for fisheries’, said Angela Andrade, Chair of the IUCN Commission on Ecosystem Management. ‘Their loss stands to be disastrous for nature and people across the globe. That is why this assessment is so important. The Red List of Ecosystems provides clear pathways on how we can reverse mangrove loss and protect these delicate ecosystems for the future, helping in turn to safeguard biodiversity, tackle the effects of climate change and support the realisation of the Global Biodiversity Framework.’

According to the assessment, without significant changes by 2050, climate change and sea level rise will result in the loss of: 

• 1.8 billion tonnes of carbon stored (17 per cent of the total current carbon stored in mangroves). 
• Protection for 2.1 million lives exposed to coastal flooding and $36 billion worth in protection to properties
• 17 million days of fishing effort per year.

The assessment claims that maintaining mangrove ecosystems across the globe will be key for mitigating the impacts of climate change. The reason for this is because the muddy soil that mangroves live in is extremely carbon-rich and over time the mangroves help to not only add to this store of soil by capturing sediment but hold it—and the carbon—in place.

This makes mangroves a nature-based solution to a man-made problem. In addition, a coastline backed with healthy mangroves is likely to be better able to cope with sea level rise and offer protection from the impacts of hurricanes, typhoons and cyclones. 

‘IUCN’s Red List of Ecosystems is key to tracking progress towards the goal of halting and reversing biodiversity loss, in line with the Kunming-Montreal Global Biodiversity Framework’, said Dr Grethel Aguilar, the IUCN Director General. ‘The first global assessment of mangrove ecosystems gives key guidance that highlights the urgent need for coordinated conservation of mangroves – crucial habitats for millions in vulnerable communities worldwide.

‘The assessment’s findings will help us work together to restore the mangrove forests that we have lost and protect the ones we still have.’

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• Marine Conservation Society’s open letter to political leaders

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New study has discovered fibreglass particles in oysters and mussels leading to worries over environmental and health implications.

By Stuart Butler

Microplastics in the marine environment have been a big subject in environmental news of late. There are trillions of bits of plastic particles floating about our oceans and many of the marine creatures we humans eat are contaminated with microplastics. These plastics are then transferred to us and the health consequences are becoming increasingly clear with microplastics having already been discovered in breast milk and testes.

Now though, to add to our list of marine pollution worries, scientists have discovered fibreglass in shellfish.

The new study, which was conducted by the Universities of Brighton and Portsmouth, and published this week in the journal Science Direct, has revealed for the first time worrying levels of fibreglass or glass reinforced plastic (GRP) particles in oysters and mussels. The study discovered that fibreglass used in boat manufacturing is breaking down and contaminating coastal waters and causing harm to marine life.

The fibreglass particles have been detected in the soft tissues of oysters and mussels collected near an active boatyard in Chichester Harbour, a popular sailing destination in the south of England. Using micro Raman spectroscopy, researchers found up to 11,220 fibreglass particles per kilogram in oysters and 2,740 particles per kilogram in mussels. 

Dr Corina Ciocan, Principal Lecturer in Marine Biology from the University of Brighton and one of the report authors, said, ‘Our findings show a disturbing level of GRP contamination in marine life. This study is the first of its kind to document such extensive contamination in natural bivalve populations. It’s a stark reminder of the hidden dangers in our environment.’ 

Fibreglass, which has been widely used since the 1960s in boat manufacturing, is known to be very durable. On the flip side though, it’s also incredibly difficult to dispose of properly and often ends up abandoned or improperly discarded. This results in tiny glass particles entering the water, especially during peak boat maintenance seasons like winter. These particles then accumulate in bivalves such as oysters and mussels, which are crucial to marine ecosystems due to their filter-feeding habits.

The study highlights the risks associated with fibreglass contamination. Bivalves, being stationary filter feeders, are highly susceptible to accumulating these particles, which can severely impact their health. The ingestion of fibreglass can interfere with their digestive systems, leading to physiological stress and even death. This not only affects marine life but could also have significant implications for human health, given that these bivalves often end up on our dinner plates.

Professor Fay Couceiro from the University of Portsmouth, and another of the report authors, said, ‘It’s a global issue, particularly for island nations with limited landfill space. Efforts are being made to find viable disposal solutions, but more needs to be done to prevent at-sea dumping and onshore burning. We’re just starting to understand the extent of fibreglass contamination. Our study is the first to show this level of contamination in natural bivalve populations.’

The consequences of this contamination are not yet fully understood, but the potential for widespread ecological – and human health- impact is significant.  The research highlights the urgent need for better regulation and management of fibreglass disposal. Commenting on this Professor Couceiro said, ‘We have to address this issue head-on to protect our marine ecosystems and ensure a healthier future for our oceans.’

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• A step towards solving the plastic pollution crisis

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A new study reveals that grey whales are rapidly shrinking and scientists fear this could have a significant impact on whale health

By Stuart Butler

The grey whale (Eschrichtius robustus, also spelt gray whale), was once known as the ‘devil fish’, for the ferocity with which they fought the whalers trying to harpoon them. Now that whalers have been replaced with whale watchers, they go by the far more appealing nickname of the ‘friendly whale’, as they are known for their curiosity and friendly behaviour towards humans, often gently approaching whale-watching boats and sometimes even allowing people to pet them.

However, a change of nickname isn’t the only thing that’s changed for grey whales. Recent studies have found that off the Pacific coast of North America, they’re also getting smaller.

Grey whales, which can weigh in at over four tonnes and grow to over fifteen metres in length, were once common throughout the Northern Hemisphere. They were driven to extinction in the Atlantic in the 18th Century and, by the 1930s hunting had reduced grey whale numbers to two extant populations, one in the Eastern and one in the Western North Pacific.

The Western Pacific population, around the Sea of Ohtosk, Japan and Korea remains very low, but the Eastern Pacific population has recovered to such an extent that it has been downgraded on the IUCN Red List of Threatened Species to being of ‘Least Concern’.

Within the larger Eastern Pacific population is a small sub-population numbering just over 200 animals, known as the Pacific Coast Feeding Group (PCFG). Studies in recent years have shown that the whales living in this subpopulation have undergone a significant decline in body length since around the year 2000, and new research by scientists from the University of St Andrews has found that this may be linked to changes in environmental conditions in the region they live.

The Marine Mammal Institute’s Geospatial Ecology of Maine Megafauna (GEMM) Lab at Oregon State University (OSU) has been studying this subgroup of grey whales since 2016, including flying drones over the whales to measure their size.

Using images taken over a seven-year period between 2016-2022 of 130 individual whales with known or estimated ages, researchers determined that a fully-grown grey whale born in 2020 is expected to reach an adult body length that is 1.65 meters (5ft 5in) shorter than a grey whale born prior to 2000 . This amounts to them losing about 13 per cent of their overall length.

The worry is that the smaller size could have major consequences for the health and reproductive success of the affected whales, and also raises alarm bells about the state of the food web in which they coexist.

‘This could be an early warning sign that the abundance of this population is starting to decline, or is not healthy,’ said Dr K C Bierlich, co-author of the study and assistant professor at OSU’s Marine Mammal Institute. ‘Whales are considered ecosystem sentinels, so if the whale population isn’t doing well, that might say a lot about the environment itself.’

Study authors note that whale calves that are smaller at weaning age may be unable to cope with the uncertainty that comes with being newly independent, which can affect survival rates and that for adult grey whales being smaller might impact reproductive success.

‘In general, size is critical for animals,’ said Dr Enrico Pirotta, lead author of the study and a researcher at the University of St Andrews in Scotland. ‘It affects their behaviour, their physiology, their life history, and it has cascading effects for the animals and for the community they’re a part of.’

Now that they know the PCFG grey whales’ body size is declining, researchers say they have a lot of new questions about how that might affect the whales in the future, and what factors could be contributing to the change.

‘We’re heading into our ninth field season studying this PCFG subgroup,’ Dr Bierlich said. ‘This is a powerful dataset that allows us to detect changes in body condition each year, so now we’re examining the environmental drivers of those changes.’

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• Featured Photographer – Kaush Subramaniam

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A video has emerged showing a sperm whale entangled in rubbish swimming up to a group of divers and apparently asking them for help

By Stuart Butler

A video has emerged showing the moving moment a sperm whale entangled in rubbish swims up to a group of divers and appears to ask them for help.

In the video, which was filmed at an undisclosed location in the Indian Ocean, the sperm whale can be seen swimming right up to a group of divers with its mouth and part of its head entangled in a web of rubbish and plants. The whale remains next to the divers, with its mouth agape, while one of the female divers carefully untangles and removes the rubbish from the whale’s jaws. Once the whale is free – rather than vanish straight back into the deep blue – the whale hangs around the divers for a while.

Although this particular story has a happy ending this isn’t the case for most marine creatures tangled in our rubbish. It’s very hard to estimate both how much rubbish enters our oceans each year and how much is already floating around entangling animals. We know that 80 per cent of the rubbish in our oceans is plastic waste and recent figures suggest that 8 million pieces of plastic pollution enter the oceans of the world every single day. Over the course of a year this amounts to 12 million tonnes.

As for how much plastic waste might have already accumulated in the ocean, one recent study estimated that there were already around 171 trillion pieces of plastic floating on the surface of the ocean alone. In addition to this waste, there’s the plastic rubbish that has sunken to the sea bed and, of course, the ever-growing threat of microplastics, which have even been found in humans through our consumption of seafood.

Plastic pollution has been found in every single corner of the oceans surveyed so far – from the deepest ocean trenches to the polar oceans. And this is only plastic waste; the problem is further compounded with other human-generated waste such as abandoned, lost and discarded fishing nets and lines (ghost gear), non-plastic waste and chemical pollution.

The oceanic plastic pollution situation is far from improving. In fact, it’s getting worse, with researchers estimating that the amount of plastic waste finding its way into the oceans each year could triple by 2040.

If all that plastic and other waste simply floated about in the ocean then that would be bad enough, but as the whale in the video demonstrates, many animals consume the plastic thinking it’s a tasty colourful morsel. A WWF study estimated that 100,000 marine mammals and turtles, and 1 million sea birds are killed by marine plastic pollution every year. And that’s only the ones we know about. Many more marine mammals, turtles and seabirds are likely to be killed through plastic consumption in the coming years.

And so, while this particular sperm whale was one of the lucky ones, other animals may not be so lucky to avoid another – potentially deadly – encounter with the plastic pollution contaminating the oceans.

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• A step towards solving the plastic pollution crisis
• Decoding sperm whales’ ‘phonetic alphabet’

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The Dominican Republic will joins a handful of other countries committed to conserving 30 per cent of its ocean waters

By Stuart Butler

With humpback whales, manatees, wrecks, caves, drift dives and coral reefs, mangrove swamps and, not forgetting of course, the idyllic Caribbean climate and delicious beaches, the Dominican Republic is a sure-fire favourite with divers. But now the island and its surrounding waters are about to get even more enticing with the announcement earlier this month that the Dominican Republic is committing itself to protecting over 30 per cent of its waters. In doing so it becomes one of only a handful of countries in the world to make such a commitment and it means the country will meet one of the targets of the Global Biodiversity Framework to conserve 30 per cent of lands, waters and seas by 2030.

Announced by ocean conservationist Sylvia Earle, the 30.8 per cent officially designation for protection includes a critical transboundary marine protected area – the first in the Caribbean – straddling the Colombian boundary on the Beata Ridge seamount, an area of critical importance for cetaceans, sea birds, and sharks. 

Surveys, funded by Blue Marine Foundation, Blue Nature Alliance and Wyss Foundation, have shown that the seamount serves as both a feeding ground and travel route for rare seabird species such as the black-capped petrel, cetaceans (sperm whales, pilot whales, dolphins), and also acts as a nursery for diverse marine species including the critically endangered oceanic whitetip shark. 

One particularly vital area that will fall under the new protections is the Silver Bank, one of the most important breeding and calving grounds for the North Atlantic humpback whale population. Every year, between January and April, thousands of these giants migrate to the warm, sheltered waters of the Silver Bank to mate, give birth, and nurse their calves.

Commenting on the announcement of the new protections, Jonathan Delance, Deputy Minister of Environment of the Dominican Republic government said, ‘We are very proud to have our new marine protected areas. The fact that we’re expanding our protected ecosystems is a huge achievement for the Dominican Republic. We’re reaching 30 per cent today, six years before the goal. We are very happy to have been in contact with so many allies around the world who shared with us their technical expertise, funding our priorities of research, so we can finally have reached this incredible goal to have protected 30 per cent of our ocean.’

Meanwhile, Dr Judith Brown, Project Director of Blue Marine Foundation, said, ‘The Government of the Dominican Republic has taken a momentous step toward marine conservation leadership with this evidence-based designation.  It will preserve migratory pathways of key species like sperm whales and advance MPA connectivity across borders, hopefully acting as a catalyst to accelerate the establishment of a network of marine protected areas throughout the Caribbean.’

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