Welcome to the April issue of SEVENSEAS. This month, we travel to Tenerife, where Europe’s first Whale Heritage Site opens a deeper look at the Atlantic’s most contested marine corridors, the threats facing the Teno-Rasca sanctuary, and the pilot whale communities whose futures hang in the balance; a seven-day itinerary and a practical guide to the island’s water quality crisis round out the coverage. From Trinidad, Katrina Khan-Roberts explores how a mermaid named Mertrina can reconnect island communities with the sea. In Ghana, West Africa’s first diving bootcamp is training a new generation of coral guards. Dr. Narissa Bax explains how Antarctic blue carbon is reshaping the climate conversation, while a URI study questions the long-term promise of marine carbon removal. On the high seas, the shadow fleet of aging tankers has crossed into geopolitical flashpoint. You’ll also find coverage of UNESCO’s Cryospheric Sciences decade, the Seaworthy Collective’s latest BlueTech cohort, and coral restoration in Accra.

Tenerife’s Whale Sanctuary and Why Teno-Rasca Matters

Europe’s first Whale Heritage Site hosts 28 cetacean species year-round, but wastewater failures, coastal development, and a contested port project now threaten the Atlantic’s most protected marine corridor. [Read more]

A Nature Traveller’s Guide to Tenerife, Seven Days Deep

Beyond the resort strip: ancient laurel forests, volcanic calderas, cave villages, and dragon trees across a seven-day itinerary through one of Europe’s most ecologically varied islands. [Read more]

Is the Water Safe? Tenerife Beach Quality in 2026

EU legal action, criminal charges, and an 81 million euro cleanup plan follow years of wastewater failures across the island. A practical guide to where swimming is safe and where caution is warranted. [Read more]

What Tenerife’s Fish Are Telling Us About Ocean Health

Four hundred fish species, resident pilot whales, and migrating bluefin tuna share waters where reef habitats and seagrass meadows are declining. The signals from the sea are mixed, and worth reading closely. [Read more]

Tenerife: Into the Habitat of Pilot Whales, Seen Up Close

Resident pilot whale pods thrive year-round in Tenerife’s deep underwater canyons, their matriarchal societies holding knowledge passed across generations. A reflection on coexistence, awareness, and what the sea asks of us. [Read more]

Small Islands and the Currents of Change in the Caribbean

From a childhood watching Trinidad’s shoreline transform to creating Mertrina the mermaid, Katrina Khan-Roberts explores how storytelling and imagination can reconnect island communities with the sea. [Read more]

How Ghana Is Training the Next Generation of Coral Guards

In Accra, two conservationists founded Coral Reefstoration Ghana and launched The Dive Lab, West Africa’s first diving and underwater media bootcamp for marine biology students. [Read more]

Carbon and Nutrient Cycles Overlooked in Marine CDR Plans

A URI study reveals that carbon and phosphorus cycle through the ocean on different timescales, creating a “productivity hangover” that may cause marine carbon removal strategies to overestimate their long-term impact. [Read more]

Celebrating World Glaciers and Water Days Through Art

UNESCO launched the Decade of Action for Cryospheric Sciences in Paris, while five side events across the U.S. connected glacier research, maritime heritage, and artistic expression at museums from Maryland to New York. [Read more]

Antarctica’s Hidden Carbon Sink and the Science of Blue

Polar marine ecologist Dr. Narissa Bax explains how phytoplankton and deep-sea organisms in the Southern Ocean are reshaping the climate conversation around Antarctic blue carbon. [Read more]

The Shadow Fleet: From Environmental Threat to Flashpoint

Over 340 aging tankers now operate outside international safety standards, as military seizures, naval escorts, and flag-switching transform a maritime environmental crisis into a contest between world powers. [Read more]

Seaworthy Collective Launches Its Seventh Startup Cohort

Seven new BlueTech startups join the NOAA-backed Continuum program, building AI and data-driven solutions for ocean mapping, water quality monitoring, fisheries health, and the growing blue economy. [Read more]

[Contact Us Today — SEVENSEAS Media]

The question visitors to Tenerife are increasingly asking before they book is one that would have seemed unusual a few years ago: is the water actually safe to swim in? It is a fair and important question, and one that deserves a straightforward, evidence-based answer rather than either alarming exaggeration or reassuring dismissal. The situation is genuinely complicated, varies significantly by location and season, and is in the middle of a politically charged response from local and national authorities.

The Scale of the Pollution Problem

The water quality crisis affecting parts of Tenerife is not a tabloid invention. In late 2025, the Court of Justice of the European Union formally condemned Spain for failing to comply with the EU’s Urban Wastewater Treatment Directive, identifying at least 12 specific locations on Tenerife where sewage collection, treatment, and discharge into coastal waters was either inadequate or entirely absent. [1] This followed years of documented failures. Environmental analysis cited by campaigners estimated that approximately 57 million litres of wastewater are discharged into Canary Islands seas every day, equivalent in volume to around 17 Olympic swimming pools. [2]

The consequences became impossible to ignore in 2024 and 2025. Playa Jardín, a well-known black-sand beach in Puerto de la Cruz on the island’s north coast, was closed for almost a year after E. coli levels in the water significantly exceeded safe limits. Investigations revealed fractured discharge pipes, pumping stations operating without legal authorisation, and a wastewater treatment plant that had gone years without the mandatory inspections and repairs. [3] In August 2025, the Public Prosecutor’s Office took the unusual step of charging six officials — including a former mayor of Puerto de la Cruz and the island’s former Tourism Department head — with environmental negligence and mismanagement of public infrastructure. [3]

The Spanish environmental NGO Ecologistas en Acción, which publishes an annual “Black Flag” report ranking the worst-managed coastal zones in Spain, awarded black flags to both Playa Jardín and Puertito de Adeje in its 2025 edition. [4] Puertito de Adeje, on the island’s southwest coast, was flagged not for E. coli but for what the organisation described as poor management in relation to new luxury coastal development and an underwater garden project that critics argue threatens endangered marine species. [4]

Storm events have made the underlying infrastructure problems dramatically visible. When Storm Claudia brought heavy rainfall in November 2025, drainage systems in Garachico and Las Américas were overwhelmed, sending wet wipes, oils, and other debris onto the shore. Beachgoers in Las Américas reported finding white, greasy masses on the sand, which chemists explained as the product of soaps and oils in wastewater reacting when pushed out to sea. [5] The Canary Islands government’s own discharge register, updated in 2025, recorded 403 coastal discharge points across the archipelago, with more than half operating without full authorisation. [1]

The Response: €81 Million and a 2030 Target

In February 2026, Tenerife’s Island Council formally presented an €81 million infrastructure plan designed to address these failures over a four-year period running through 2030. The plan covers modernising outdated wastewater networks, increasing treatment capacity, preventing unauthorised coastal discharges, and improving coordination between the island’s municipalities, which have historically operated fragmented and sometimes incompatible sanitation systems. [6] Vice President Lope Afonso framed the initiative around a “zero waste” ambition and called on all local municipalities to participate in the 2027-2030 Cooperation Plan. [6]

The plan has been welcomed cautiously by environmental groups. The Tenerife Association of Friends of Nature (ATAN), which was among the first organisations to raise public alarms about the contamination crisis in early 2026, has called for more transparency about the actual scale of coastal pollution and demanded that tourists be given honest information about water quality at specific beaches rather than generic reassurances. [1] This tension between the island’s economic dependence on tourism and the imperative to communicate environmental problems honestly is not going away quickly.

Where Is It Actually Safe to Swim?

The water quality situation varies significantly across Tenerife’s coastline, and not all beaches are affected equally. The problems documented in official reports are concentrated primarily in the north of the island, around Puerto de la Cruz and parts of the northeast coast, and in specific southern locations where infrastructure has struggled to keep pace with resort development.

The southern resort strip between Los Cristianos and Costa Adeje generally maintains higher water quality, supported by more recently built sanitation infrastructure and EU Blue Flag certification at several beaches. Blue Flag status, awarded annually by the Foundation for Environmental Education, requires compliance with strict water quality testing, environmental management standards, and safety requirements — making it the most reliable indicator of consistently clean swimming water available to visitors. [7]

Practical guidance for 2026 visitors: check the current flag status at your specific beach on arrival, not the status from a previous season. Red flag means swimming is forbidden, regardless of the reason. Avoid swimming within 48 hours of heavy rainfall anywhere on the island, as storm runoff affects even beaches that are generally well managed. The north coast, including the Puerto de la Cruz area, carries higher current risk than the southwest. Beaches within the southern resort area with active Blue Flag certification — including Playa de Troya, Playa del Duque, and Las Vistas in Los Cristianos — are your safest options while the infrastructure improvements work their way through the system.

Looking Ahead

Tenerife’s coastal pollution crisis is real, but it is being taken seriously in a way it was not a few years ago. EU legal pressure, criminal charges against officials, a significant funding commitment, and genuine civic pressure from environmental organisations have combined to produce a political response with specific targets and timelines. Whether that response is adequate, and whether it moves fast enough to protect both public health and the island’s reputation, is a question that will be answered in the coming years.

What is certain is that the era of uncritical optimism about Tenerife’s beach water quality is over. Visitors deserve accurate information, and the island’s long-term interests as a destination are better served by honest communication than by silence.

Sources

1. BritBrief: Health alert for Canary Islands — tourists warned about beach water pollution, britbrief.co.uk, January 2026
2. National World: Warning to avoid 48 Black Flag beaches in Spain, nationalworld.com, June 2024
3. DaNews.eu: Prosecutor charges six officials over pollution at Playa Jardín in Tenerife, August 2025
4. Travel Tomorrow: Tenerife set to invest €81 million to clean up island’s coastline and reputation, traveltomorrow.com, February 2026
5. Canarian Weekly: Waste and pollution wash up on Tenerife’s coastline again, canarianweekly.com
6. Travel and Tour World: Tenerife Plans to Invest Eighty Million Euros in Overhauling Water and Sanitation Infrastructure, travelandtourworld.com, February 2026
7. Curious Expeditions: Is the sea clean in Tenerife?, curiousexpeditions.org, March 2026

There are few places in Europe where you can watch a pod of short-finned pilot whales (Globicephala macrorhynchus) year-round from a small boat, barely twenty minutes from shore. Tenerife is one of them. The waters along the island’s southwestern coast host one of the most biodiverse marine corridors in the Atlantic, a stretch of deep, warm sea that has earned formal protection at both Spanish and European level — and a designation that no other place on the continent shares. Understanding what makes this ecosystem extraordinary is also, increasingly, a matter of understanding what threatens it.

A Marine Sanctuary Unlike Any Other in Europe

The Teno-Rasca Special Area of Conservation (ZEC Teno-Rasca) runs along roughly 80 kilometres of Tenerife’s western coastline, from the Teno Massif in the north to Punta Rasca in the south. It covers approximately 76,648 hectares of ocean, reaching depths of around 2,000 metres at its farthest southern point, and it forms the largest Special Area of Conservation in the Canary Islands within the European Natura 2000 network. [1]

What sets this stretch of water apart is geography. The island rises steeply from the ocean floor, and the deep underwater trenches close to shore create conditions that would normally only exist far out to sea: cold, nutrient-rich upwellings meeting warm surface waters, producing a dense food web that supports an exceptional concentration of marine life. Up to 28 species of cetaceans have been recorded here. [2] Most remarkable among them are the short-finned pilot whales, a resident population that does not migrate and can be reliably observed on almost any given day of the year, making Tenerife one of the very few places on Earth where this is possible. [3]

Alongside the pilot whales, bottlenose dolphins (Tursiops truncatus) maintain a permanent presence, while Atlantic spotted dolphins (Stenella frontalis), striped dolphins (Stenella coeruleoalba), and occasional transient species such as fin whales, sperm whales, and orcas are recorded seasonally. Loggerhead sea turtles (Caretta caretta) and green turtles (Chelonia mydas) inhabit the waters throughout the year, and hawksbill (Eretmochelys imbricata) and leatherback turtles (Dermochelys coriacea) are occasional visitors. [1]

Beneath the surface, the seabed is equally rich. The reserve contains sandbanks, rocky reefs, marine caves, and extensive meadows of seagrass known locally as sebadales — underwater prairies of Cymodocea nodosa that function as nurseries for juvenile fish, feeding grounds for sea turtles, and significant carbon sinks. These habitats are listed under the EU Habitats Directive as priority ecosystems requiring active conservation. [1]

In January 2021, the World Cetacean Alliance formally designated the Tenerife-La Gomera marine area as Europe’s first Whale Heritage Site, and the third in the world, recognising not only the ecological richness of the zone but also the island’s commitment to responsible marine tourism practices. [2] Mission Blue, the ocean conservation organisation founded by marine biologist Sylvia Earle, has also declared the area a Hope Spot in support of further protection efforts. [1]

Why the Coastal Crisis Threatens What the Reserve Protects

Recognition and legal protection do not automatically translate into good environmental outcomes, and the Teno-Rasca reserve exists within a broader coastal context that is under serious pressure. Tenerife welcomed 16.3 million visitors in 2025, and the strain that level of tourism places on the island’s infrastructure is becoming visible in its waters. [4]

The same coastline that contains Europe’s whale sanctuary also borders one of Spain’s most troubled wastewater management systems. Environmental NGO Ecologistas en Acción documented that approximately 57 million litres of wastewater are discharged into Canary Islands seas every single day, and the Court of Justice of the European Union formally condemned Spain in late 2025 for failing to adequately treat urban wastewater, identifying at least 12 critical locations on Tenerife alone. [5] While the worst contamination has been concentrated in the north and south of the island rather than in the heart of the marine reserve itself, discharges of this scale and consistency create cumulative effects across an interconnected ocean system. Microplastics, pharmaceutical residues, and nutrient pollution from sewage all move with currents, affecting the entire marine corridor.

The EU-funded OCEAN CITIZEN project, which selected Tenerife as its primary pilot site for marine restoration in 2024, has documented what decades of compounding pressures have already done: once-thriving fish populations have declined significantly, rocky reefs have been damaged, and seagrass meadows have retreated in several areas of the island due to a combination of pollution, overfishing, and rising ocean temperatures. [6] The project is working to address these losses through seagrass replanting, coral restoration including gorgonians and black coral populations, drone-based monitoring, and community engagement programmes designed to connect local residents to the conservation process.

There is also a contested infrastructure question. For several years, plans have existed to construct a new commercial port at Fonsalía, a location that sits within the Teno-Rasca conservation zone. Critics, including the international marine conservation organisation OceanCare, argue that the project was only made possible because the relevant coastal section was cut out of the protected area designation, not because it was less biodiverse. Local civic groups have organised in opposition under the name Plataforma Ciudadana Salvar Fonsalía. [7] The outcome of this dispute will have direct implications for the ecological integrity of Europe’s flagship whale sanctuary.

The Bigger Picture

Tenerife’s marine environment represents something genuinely irreplaceable in a European context. A resident population of pilot whales, 28 recorded cetacean species, seagrass meadows, deep-water reefs, and sea turtles, all within 12 nautical miles of a major tourist island, is a combination that exists nowhere else on the continent. The Teno-Rasca designation, the Whale Heritage Site status, and the OCEAN CITIZEN restoration programme all reflect a serious scientific and institutional recognition of what is at stake.

What is needed now is the political and economic will to match those designations with real infrastructure investment, consistent enforcement, and honest public communication about the health of these waters. The sea does not lie. And the pilot whales, whose ancestors have made this coastal channel their home for longer than any human record, are paying attention.

Sources

1. Teno-Rasca Marine Strip Special Area of Conservation overview, TenerifeDolphin.com and TenerifeWhaleWatching.com
2. AD Boat Rental: Tenerife — Europe’s First Whale Sanctuary, adboatrental.com
3. Whale Watch Tenerife, whale watching season data 2023-2025, whalewatchtenerife.org
4. Timeout: Tenerife Is Investing €81 Million Into A Massive Coastal Clean Up, timeout.com, March 2026
5. BritBrief: Health alert for Canary Islands — tourists warned about beach water pollution, britbrief.co.uk, January 2026
6. OceanCitizen EU: Reclaiming Tenerife’s Ocean, oceancitizen.eu, September 2024
7. OceanCare: Whales and Dolphins Off Tenerife in Danger, oceancare.org