Rewilding the Sea

1. The Ocean's Hidden Potential for Rewilding and Conservation

"To rewild the sea is to bring back lost and depleted species to our oceans and restore ecosystems that have been harmed by human activities – simply by stepping back and letting nature repair the damage, or by reintroducing species or restoring habitats."

Rewilding the sea is a powerful concept that involves allowing nature to reclaim and restore marine ecosystems. This approach recognizes the ocean's inherent ability to heal itself when given the opportunity. By removing or reducing human pressures, such as overfishing and destructive practices, marine environments can recover their biodiversity and ecological functions.

Examples of successful rewilding efforts include:

• The return of bluefin tuna to the English Channel after decades of absence
• The recovery of coral reefs in protected areas
• The resurgence of native oyster populations in restored habitats

These success stories demonstrate that rewilding can lead to:

• Increased biodiversity
• Improved ecosystem resilience
• Enhanced carbon sequestration
• Sustainable fisheries

2. Successful Marine Protected Areas: From Chagos to Lyme Bay

"For the ocean at that time, it is probably not an overstatement to say the creation of the world's largest no-take reserve was a moment not unlike the creation of one of the great American national parks."

Marine Protected Areas (MPAs) have proven to be effective tools for conservation and rewilding efforts. The Chagos Marine Reserve, established in 2010, stands as a prime example of large-scale ocean protection. This vast area, covering 640,000 square kilometers in the Indian Ocean, has become a refuge for coral reefs, fish populations, and other marine life.

Key benefits of well-managed MPAs:

• Increased fish biomass and diversity
• Protection of critical habitats
• Spillover effects that benefit adjacent fishing areas
• Scientific research opportunities

The success of Lyme Bay in the UK demonstrates that even smaller protected areas can have significant impacts. By banning bottom trawling and dredging, Lyme Bay has seen:

• A fourfold increase in commercially targeted fish species
• Recovery of fragile reef ecosystems
• Improved livelihoods for local small-scale fishers

These examples highlight the potential for MPAs to serve as powerful tools for marine conservation and sustainable resource management.

3. The Native Oyster: A Keystone Species for Ecosystem Restoration

"According to research by the University of Portsmouth, an astonishing 466 species are associated with native oyster beds. This makes the native oyster what scientists call a keystone species – an organism that helps define an ecosystem."

Native oysters play a crucial role in marine ecosystems, acting as ecosystem engineers and supporting a wide array of biodiversity. The European flat oyster (Ostrea edulis) has been decimated by overfishing, disease, and habitat destruction, but efforts to restore this species are underway in many coastal areas.

Benefits of oyster restoration:

• Water filtration (a single adult oyster can filter up to 140 liters of water per day)
• Creation of complex habitat structures for other species
• Shoreline protection and erosion control
• Carbon sequestration

Restoration projects, such as those in the Solent in southern England, demonstrate the potential for bringing back this important species. By reintroducing oysters and providing suitable settlement substrates, these projects aim to recreate self-sustaining oyster reefs that can once again support thriving marine ecosystems.

4. Climate Change and the Crucial Role of Blue Carbon

"The ocean floor is the world's largest carbon storehouse. It follows that if we stir up the mud and fell the forests that live on the rocky bottoms, we are likely to alter the amount of carbon reaching the atmosphere, either by preventing it being trapped by living creatures or by oxidising the sediments and making it harder for the sea to absorb carbon, which it does in vast quantities."

Blue carbon refers to the carbon captured and stored by marine and coastal ecosystems. These habitats, including mangroves, seagrasses, and salt marshes, are incredibly efficient at sequestering carbon dioxide from the atmosphere. However, they are under threat from coastal development, pollution, and climate change.

Key blue carbon ecosystems and their carbon storage potential:

• Mangroves: Can store up to 10 times more carbon per hectare than terrestrial forests
• Seagrasses: Responsible for 10% of the ocean's total carbon burial
• Salt marshes: Can sequester carbon for thousands of years in their soils

Protecting and restoring these ecosystems is crucial for:

• Mitigating climate change
• Enhancing coastal resilience
• Preserving biodiversity
• Supporting local livelihoods

Recent research has also highlighted the importance of the open ocean and deep-sea sediments in carbon storage, emphasizing the need for a comprehensive approach to ocean conservation and climate change mitigation.

5. Overfishing: The Greatest Threat to Marine Biodiversity

"The UN Food and Agriculture Organisation, the state of harvestable fish stocks continues to decline. In its latest assessment of the state of wild capture fisheries, the organisation conceded that some 94 per cent of all fish stocks were now either fully exploited or over-exploited, with the over-exploited element accounting for 34 per cent of the whole."

Overfishing remains one of the most significant threats to marine ecosystems worldwide. The relentless pursuit of ever-diminishing fish stocks has led to the collapse of many commercially important species and disrupted entire food webs.

Consequences of overfishing:

• Depletion of fish populations, sometimes to the point of commercial extinction
• Disruption of marine food webs and ecosystem functions
• Economic hardship for fishing communities
• Loss of genetic diversity in fish populations

Examples of overfishing impacts:

• The collapse of cod stocks in the North Atlantic
• Depletion of bluefin tuna populations in the Mediterranean
• Overexploitation of shark species for their fins

Addressing overfishing requires a multi-faceted approach, including:

• Science-based catch limits and quotas
• Effective enforcement of fishing regulations
• Creation of marine protected areas
• Support for sustainable fishing practices

6. Industrial Fishing: Subsidies and Distant-Water Fleets

"China's distant-water fishing fleet is sighted almost everywhere: trawling for krill within sight of penguin colonies in the Antarctic; fishing in a huge armada off the Galápagos marine reserve in the tropical Pacific; jigging for squid in North Korean waters, to the extent that local fishermen starved; trawling with licences granted by poor nations in the waters off West Africa and knocking on the doors of small nations in the Caribbean."

Industrial fishing fleets, particularly those operating in distant waters, pose a significant threat to global fish stocks and marine ecosystems. These fleets, often heavily subsidized by their governments, can deplete fish populations far from their home waters, impacting local communities and ecosystems.

Key issues with industrial distant-water fleets:

• Overcapacity due to government subsidies
• Illegal, unreported, and unregulated (IUU) fishing
• Bycatch of non-target species
• Destruction of sensitive habitats through bottom trawling

The role of subsidies:

• Global fishing subsidies amount to $35 billion annually
• Harmful subsidies, such as fuel tax exemptions, account for 60% of the total
• These subsidies enable fleets to fish in otherwise unprofitable areas

Efforts to address this issue include:

• World Trade Organization negotiations to eliminate harmful fishing subsidies
• Improved monitoring and enforcement of fishing activities in international waters
• Support for small-scale, sustainable fishing practices in developing nations

7. The Future of Fishing: Artisanal and Sustainable Practices

"Daniel Pauly, the great fisheries scientist, has argued – as I've alluded to previously in this book – that the future of fishing is artisanal. He sees the fishing fleets of the future as going out 40 miles at most and leaving the high seas as a bank to create fish and carbon."

Artisanal fishing represents a more sustainable and equitable approach to harvesting marine resources. These small-scale operations typically use selective fishing methods, have lower environmental impacts, and provide greater economic benefits to local communities.

Advantages of artisanal fishing:

• Lower bycatch rates
• Reduced fuel consumption and carbon emissions
• Stronger connection to local markets and communities
• Preservation of traditional knowledge and cultural practices

Examples of sustainable fishing practices:

• Pole-and-line tuna fishing in the Maldives
• Handline fishing for cod in Norway
• Small-scale trap fishing for lobster in Maine

Promoting artisanal fishing requires:

• Policy support and legal recognition for small-scale fishers
• Investment in infrastructure and market access
• Training in sustainable fishing methods and business management
• Creation of exclusive fishing zones for small-scale operators

8. Trawling's Impact on Seabed Ecosystems and Carbon Storage

"The carbon emissions from trawling globally were likely to be equivalent to the aviation industry."

Bottom trawling, a fishing method that involves dragging heavy nets across the seafloor, has devastating impacts on marine ecosystems and may contribute significantly to climate change. This practice not only destroys sensitive habitats but also releases stored carbon from marine sediments.

Ecological impacts of bottom trawling:

• Destruction of seabed habitats, including coral reefs and sponge gardens
• Reduction in benthic biodiversity
• Alteration of seafloor topography and sediment composition
• Disruption of nutrient cycling and food webs

Carbon release from trawling:

• Disturbance of carbon-rich sediments
• Reduction in the ocean's capacity to sequester carbon
• Potential acceleration of ocean acidification

Alternatives to bottom trawling:

• Mid-water trawling for pelagic species
• Longline fishing for demersal fish
• Trap and pot fishing for shellfish
• Development of low-impact trawl gear designs

9. Kelp Forests: Underwater Oases of Biodiversity and Carbon Sequestration

"Kelp forest can take up to 20 times more carbon dioxide from the atmosphere than land-based forest."

Kelp forests are among the most productive and diverse ecosystems on Earth. These underwater forests provide crucial habitat for numerous marine species and play a significant role in carbon sequestration and coastal protection.

Benefits of kelp forests:

• High primary productivity and carbon uptake
• Habitat provision for hundreds of species
• Coastal protection from storms and erosion
• Economic value through fisheries and tourism

Threats to kelp forests:

• Ocean warming and marine heatwaves
• Overgrazing by sea urchins (often due to loss of predators)
• Pollution and sedimentation
• Physical destruction from bottom trawling

Restoration efforts, such as those in Sussex Bay, UK, demonstrate the potential for rapid recovery of kelp ecosystems when destructive practices are halted. These projects not only enhance biodiversity but also contribute to climate change mitigation and adaptation.

10. Marine Megafauna: Whales, Sharks, and Their Ecological Importance

"The International Monetary Fund has estimated the value of a single great whale at $2 million and values the current stock of great whales at $1 trillion. This calculation is based on each whale's contribution to carbon capture, stimulating fish stocks and whale-watching tourism."

Marine megafauna, including whales, sharks, and large fish, play crucial roles in ocean ecosystems. These animals are not only charismatic and economically valuable for tourism but also contribute significantly to ecosystem functioning and climate regulation.

Ecological roles of marine megafauna:

• Nutrient cycling through the "whale pump" effect
• Carbon sequestration (whale falls can store carbon for centuries)
• Regulation of prey populations
• Maintenance of ecosystem balance

Conservation challenges:

Last updated: October 13, 2024