Saturday, October 15, 2022

Rocking the Isles of Scilly


From NASA
 
An astronaut aboard the International Space Station (ISS) shot this photograph that captures a some of the essence of tidal features around the Isles of Scilly, an archipelago located just southwest of Cornwall, England.
The archipelago includes nearly 150 islands in the Celtic Sea, of which five are inhabited. Pictured are St. Mary’s, Tresco, St. Martin’s, Bryher, and St. Agnes—the largest islands in the chain.
Some of the coastal waters surrounding the islands have a bright turquoise hue, indicating the presence of shallow reefs and shoals.
 
Nautical raster chart (UKHO) with the GeoGarage platfrom
 
Deeper waters have richer blue hues.
This photo also captures swell patterns caused by waves that intersect one another as they move around the islands due to the westerly sea breeze.
The Isles of Scilly are remnants of the underlying Cornubian Batholith—a mass of ancient volcanic rock (a plutonic intrusion) that formed the Cornish Peninsula.
This intrusion originated with the crystallization of magma into igneous rock approximately 290 million years ago.
It now sits an estimated 10 kilometers (6 miles) below the surface.
Tides ebb and flow throughout the year and, at their lowest, can expose sandbars that allow people to walk between some islands.
Low tides also can expose large rocks along the shore that are used by gray seals to bask in the sun.
And bottlenose dolphins migrate with the tidal cycles here—most notably during high tides— in search of fish to feed on.
 
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Friday, October 14, 2022

Surveying the Tonga volcano eruption aftermath

A detailed look at the undersea impact
Aerial view of the Hunga-Tonga Hunga-Ha’apai (HT-HH) volcano.
(Image courtesy: SEA-KIT NIWA-Nippon Foundation TESMaP survey team)

From Hydro by Ben Simpson & Jamie McMichaƫl-Phillips

The Tonga Eruption Seabed Mapping Project (TESMaP) is a collaborative mission to discover the undersea impacts of the January 2022 eruption of the Hunga-Tonga Hunga-Ha’apai volcano.
Using their collective knowledge, experience and resources, New Zealand’s National Institute of Water and Atmospheric Research (NIWA) and The Nippon Foundation of Japan hope to understand what happened, how much material was displaced and what shape the volcano was left in.
This information will help to improve tsunami forecasting and better predict the blast effects of subsea volcanoes, which in turn will help to protect people from similar natural disasters in the future.

On 15 January 2022, a South Pacific nation with just over 104,000 residents witnessed the unexpected and unprecedented eruption of the Hunga-Tonga Hunga-Ha’apai (HT–HH) volcano.
The immediate impact had catastrophic consequences for Tonga’s nearby islands.
The main island of Tongatapu was carpeted in toxic ash and a sonic boom travelled around the globe.
The shape of the seabed greatly influenced the speed and size of the resulting tsunami; death and damage were recorded as far away as South America, and waves hit Australia, New Zealand and Japan, even touching the shores of California, Alaska and Chile.
It also severed the submarine fibre-optic cables connecting Tonga with the world, leaving the country in a prolonged blackout.

In April 2022, New Zealand’s National Institute of Water and Atmospheric Research (NIWA) and The Nippon Foundation of Japan announced a collaborative mission to discover the undersea impacts of the explosion, using their collective knowledge, experience and resources to build a detailed and invaluable picture of the eruption’s aftermath below the ocean’s surface.
The Tonga Eruption Seabed Mapping Project (TESMaP) is funded by The Nippon Foundation and supported by The Nippon Foundation-GEBCO Seabed 2030 Project, which aims to map the world’s entire ocean floor by 2030 and to deliver this information via a freely available definitive map.

Modelling Future Eruptions

Around 680 million people currently live in coastal areas, and this figure is expected to increase to one billion in less than 30 years’ time.
These coastal communities face the growing threat of storm surges and tsunamis that can wash away entire neighbourhoods and endanger lives in a matter of minutes.
Since there are numerous similar volcanos around the globe, particularly along the Pacific Ring of Fire, the eruption of HT–HH highlights a critical risk to society, exacerbated by a lack of knowledge.
Through detailed research and surveys, expanding the collective knowledge of the undersea topography is vital to understanding what happened, how much material was displaced and what shape the volcano was left in.
This information makes it possible to improve tsunami forecasting and better predict the blast effects of subsea volcanoes, which in turn will help to protect people from similar natural disasters in the future.

Phase one of TESMaP, which took place between April and May, saw NIWA scientists on board the research vessel RV Tangaroa survey the ocean around HT–HH, covering thousands of square kilometres and collecting video images of the eruption’s impact.
Phase two, which took place between July and August, utilized SEA-KIT International’s 12m uncrewed surface vessel (USV) Maxlimer to conduct a month of further mapping inside the caldera.
This research – conducted in an area which could not be surveyed by NIWA due to safety reasons – will prove crucial to the overall findings of the project.

SEA-KIT USV Maxlimer getting prepared for despatch to Tonga.

Displaced Material

Due to the sheer magnitude of the explosion, dramatic changes to the volcano were to be expected.
But instead, researchers on board RV Tangaroa for the month-long expedition were amazed to find it still largely intact.
NIWA scientists mapped a total of 22,000km2 of the surrounding seafloor and observed changes covering an area of 8,000km2.
They recorded up to seven cubic kilometres of displaced material – enough to fill three million Olympic-sized swimming pools.
Tonga’s severed domestic internet cable was buried under 30m of ash and sediment, and scientists found sandy mud and deep ash ripples as far as 50km away from the volcano.

Ecosystem Impacts

The impacts on the ecosystem were also examined.
The volcano was devoid of biology, but remarkably there were features as close as 15km away that still had abundant and diverse populations of marine life.
Surrounding seamounts had pockets of normal biodiversity, such as corals, sponges, starfish and mussels, indicating the resilience of such marine ecosystems and giving scientists a baseline for monitoring recovery in the future.
Preliminary water column data showed that it is still recovering, with some airborne ash yet to completely settle on the seafloor.
There is also evidence to suggest the volcano may still be erupting, with a dense ash layer found in the upper water column near the site.

USV Maxlimer in Tonga.
Mapping the Gaps with USV


As part of phase two, USV Maxlimer mapped the current shape of the caldera and measured environmental conditions of the water above it, all whilst being controlled remotely from SEA-KIT’s base in the UK, some 16,000km away.
The use of USV Maxlimer as a configurable platform for a range of sensors provided a unique opportunity to gather data safely and continuously from inside the caldera over a full month.
During the mission, USV Maxlimer used just 100 litres of fuel per day, which is under 2% of the fuel consumption of a typical survey vessel.
In addition to reducing the risk to people, deployment of a USV for survey inside the caldera ensures carbon emissions for the project remain low.

This was the first time that a USV had been used for this type of mission and demonstrated how the technology is pioneering new ways of understanding our oceans.
Maxlimer, the first SEA-KIT X-class USV, is the company’s testing and development vessel.
She was part of the winning Nippon Foundation-GEBCO alumni entry in 2019’s Shell Ocean Discovery XPRIZE and has since achieved numerous ‘firsts’, including the first uncrewed offshore pipeline inspection and first international commercial uncrewed transit in 2019.
The USV also completed 22 days of remote survey operations on Europe’s continental margin in 2020, mapping over 1,000km2 of ocean floor.

Real-time Data Collection

Sensors on board collected bathymetric data, water column backscatter data, sound velocity, conductivity, temperature, turbidity, oxidation reduction, pressure with depth and current data, all of which will develop and support understanding of the eruption’s undersea impact and ongoing activity.
The USV used newly fitted winch capability for sensor dips and tows to gather water column data as far down as 300m and provide a closer look at the suspended sediment layer.
This collection of oceanographic data will help to identify layers of geothermal activity as well as the change in salinity and dissolved particles, and will be used for comparison studies against samples gathered outside the caldera by RV Tangaroa.

Maxlimer, together with three members of the SEA-KIT team, was based in Nuku’alofa, Tonga for around 40 days.
During this time, the vessel was also available for use for environmental surveys ahead of possible new cable lays to reconnect the islands, as well as for the mapping of other volcanoes in the area and generating change maps from previous eruptions.

SEA-KIT USV Maxlimer returning from HT-HH caldera in Tonga.
 
Links :

Thursday, October 13, 2022

River deltas are running out of land

Many river deltas, such as the Mississippi delta, are not getting enough sediment to sustain the current amount of dry land.
Photo by Claudia Weinmann/Alamy Stock Photo
 
The Mississippi River Delta offers a beautiful combo of layers & colors while its waters meet the Gulf of Mexico. That it is the 7th largest river delta on Earth
Copenicus Sentinel 2 22-09-29) 
Courtesy of Iban Amestoy 

From Hakai Mag by J.Besl


Estimates of many deltas’ stabilities in the face of sea level rise were overoptimistic.

Millions of people live on river deltas, occupying land that exists in the delicate balance between a river’s push and the ocean’s pull.
Deltas are inherently transient, but
according to a new study, many may be even more precarious than once thought, with unexpectedly high levels of land loss threatening to submerge these low-lying landscapes.

The insight that many deltas are degrading even faster than previously estimated stems from a new analysis of sediment flow rates led by Austin Chadwick, a geomorphologist at the California Institute of Technology.

When a river reaches the delta, its flow slows and it begins dropping the sediment it carries, bolstering the land in the process.
To date, geologists working to predict the future of a particular delta commonly compare the pace of sea level rise to the rate of sediment deposition.
Their models assume sediment is spread evenly across the delta.
But that’s not a realistic scenario, says Chadwick.

“The previous work has been very much a best-case scenario,” he says.
“A river actually can’t be everywhere at once, and it can’t fight back against sea level rise everywhere.”

In reality, a river only builds new land where it’s currently flowing.
Sediment deposited out of the water forms wide sandy pancakes called lobes.
When too much sediment accumulates and blocks the river’s path, the river will jump course and start building a new lobe elsewhere.
The old lobe, cut off from the sediment supply, will start to erode.

Chadwick and his team wanted to quantify how much land is gained and lost during these jumps and estimate how much future engineering projects can mitigate this land loss.
They modeled a delta system using a new equation that factors in the interplay between sea level rise and river lobes’ unequal growth.
They then confirmed the model using an artificial miniature delta in their lab before applying their findings to actual river systems.

The researchers’ prognosis for many deltas is bleak.
The scientists estimate that given the pace of sea level rise, the Mississippi River, for instance, needs to deliver three times more sediment to the delta than previous estimates suggest to maintain the current area of dry land.
Romania’s Danube River delta has it worse—it needs 10 times its current supply of sediment.
In most cases, that’s more grit than the river can supply, suggesting these deltas are doomed to drown.

The new forecasting method, says Chadwick, “gives you a more realistic, but also a little bit more pressing, prediction.”

Not all deltas are in danger, though.
China’s gritty Yellow River is so thick with sediment that it jumps course and forms a new lobe every decade.
Engineers have even been able to corral the river with diversions to focus the firehose of sediment and bolster land in select locations.
These sorts of projects come at a steep engineering and ecosystem cost, but they maximize the river’s land-building potential.
Without diversions, a river may waste that much-needed sediment by pipelining it into the open ocean or building a lobe and abandoning it.
For regions that can afford it, diversions offer a path to ensuring there is persistently dry and habitable land in choice delta regions.

Very few rivers, however, have the massive sediment supply of the super-silty Yellow River.
The Mississippi River, in comparison, naturally switches course every 2,000 years.
Louisiana’s Coastal Master Plan recommends diversions in some locations and river dredging elsewhere to build marshes and stabilize banks.

The clock is ticking for the mouth of the Mississippi and many other deltas.
As the ocean rises, engineers will need even more sediment to fill the deeper water, says Ehab Meselhe, a civil engineering professor at Tulane University in Louisiana.
A restoration solution that works today may not work 10 years from now.
“The sooner we implement projects, the more likely they are to succeed,” Meselhe explains.
“Time,” he adds, “is not on our side.”
 
Links :

Wednesday, October 12, 2022

UKHO: The next generation of navigation technology will transform shipping



From Safety4Sea by Peter Sparkes

UKHO’s Chief Executive, Peter Sparkes, refers to the radical changes that S-100 suite of standards will bring to navigational safety, highlighting that the future is digital.
In that regard, UKHO is currently in a transition phase up to 2026 as it is withdrawing from paper chart production, supporting users to unlock the benefits that digital navigation brings.


The shipping industry is navigating an era of unparalleled change and a digital transformation, Mr .Sparkes says, adding that, in that regard, it is vital to understand the marine context in which we operate to successfully enhance not only safety but also decarbonizing efforts.

SAFETY4SEA: What are the top priorities on your agenda for the next five years?

Peter Sparkes: The future of shipping will be underpinned by digital innovation, enhanced satellite connectivity at sea, and data-driven decision-support solutions that better optimise operations.
Meanwhile, the next generation of electronic navigational charting data standards (S-100) will greatly enhance the safety and efficiency of maritime navigation.
Our aim is to be at the forefront of the industry’s digital transition, continuing to provide the assured and globally trusted ADMIRALTY Maritime Data Solutions that the world’s seafarers depend on.

An increasingly digital maritime industry will be shaped by the International Hydrographic Organization’s new universal S-100 data standards – which we will support as one of our top priorities – fusing and enriching navigational products and services.
S-100 will also enable fleet operations and supply chains to work in closer harmony, to unlock a new level of port access, transparency and support in near real-time.
The new standards will dramatically reduce the time that vessels need to wait for important navigational and safety updates, improving the safety of life at sea and supporting enhanced voyage optimisation and weather avoidance.
We seek to play a leading role in advancing the development of these new digital standards by working with users, providers and partners to test product specifications, build safety cases, improve the user experience and fully realise the undoubted potential of the S-100 suite of standards.

S4S: Following your recent announcement, what are the key barriers and drivers with regards to the digital transformation within the industry that you are currently facing?

P.Sp: We understand and acknowledge the significance of our announcement to withdraw from global paper chart production by 2026, given our history of creating standard nautical charts (SNCs) and the trust that mariners have long placed in ADMIRALTY charts.
Generating timely and effective digital alternatives and managing a smooth transition is a responsibility we feel keenly.
The last 10 years have seen a rapid decline in user demand for paper charts, driven by the SOLAS-mandated transition to ECDIS and growing recognition of the wider operational benefits of digital solutions, including the next generation of navigation services.
In 2011, 80% of ADMIRALTY products sold were paper based, with 20% digital.
In 2021, 84% of ADMIRALTY products sold were digital, while only 16% were paper based so demand is declining at about 17% per annum.
Our users are telling us they want and need digital solutions.
They need to know where they are, not where they were.
Withdrawing from paper chart production enables us to greatly increase our focus on digital navigation products and services that we will be able to update in near real-time, greatly enhancing safety of life at sea.
During the transition period, we will support users of SNCs and work with our distributor channel to help users switch to digital alternatives, between now and 2026.
The key message is, we want to take all our ADMIRALTY users with us, greatly improving our support for them and helping them to unlock the benefits that digital navigation brings.

S4S: What changes should we expect to see following the transition to a digital chart portfolio by 2026?

P.Sp: The UKHO has produced first-generation electronic navigational charts (S57 ENCs) for nearly 20 years, with 18,000+ cells now available through the global ADMIRALTY Vector Chart Service (AVCS).
Our extensive international portfolio of ENCs, which meet flag and port State requirements, help bridge crews, navies and shipping companies to navigate safely and efficiently, whilst helping inform the operational and investment decisions of charterers and other key stakeholders.
Our strategy to withdraw from paper chart production is centred around reducing and eventually removing our paper chart portfolio, in line with user needs, market trends and commercial viability.
It will happen in a phased and carefully managed transitionary approach, in close consultation with our customers, partner hydrographic offices and regulatory bodies, including the UK Maritime and Coastguard Agency (MCA).
As we withdraw paper charts, we will focus on providing users with authoritative digital alternatives to meet their demands and those of regulatory bodies, phasing out SNC coverage in a way that is safe for mariners and sustainable for the UKHO.
The withdrawal of paper charts does not include paper publications, which we will continue to support.
However, we are also developing a much improved, far more user-friendly ADMIRALTY Digital Publication solution, too.

S4S: What advice would you give to industry stakeholders for safer navigation in the digital age?

P.Sp: The shipping industry is navigating an era of unparalleled change and a digital transformation.
But despite the pace and scale of these challenges, the next generation of navigation technology will deliver a huge leap forward in positional and situation awareness capability, providing tools that will enable us to make smarter, faster decisions about the operations of our vessels, and deliver the safe, secure, and thriving oceans that we all seek.
Better understanding the marine context in which we operate is fundamental to successfully protecting our oceans, coastlines, and environment, as well as to decarbonising maritime operations.
Cleaner fuels and novel propulsion technologies will play a significant role in reducing shipping’s carbon impact.
High-fidelity navigational data can, in the near-term, also help to unlock significant latent operational efficiencies in our ports and in how we operate ships.
Together, we can help to enhance voyage and route optimisation, expedite port operations, and enable ‘smarter steaming’ and ‘Just in Time’ arrivals.

S4S: What does the industry need to start doing differently to prepare for a smarter and digitalised future?

P.Sp: For me as a former mariner, what’s really exciting is the scale of the latent potential that we can help realise.
Data-based vessel, voyage and fleet optimisation is particularly interesting, as are the impacts of heavy weather avoidance, slower steaming and ‘Just in Time’ arrivals as they become operational norms.
A recent ‘Seas at Risk and Transport & Environment’ report identified that by reducing speeds across the global fleet by 20% – which is an achievable by-product of ‘Just in Time’ – we may be able to reduce shipping’s carbon footprint by a remarkable 34%.
This means that the potential impact of smarter navigation, enabled by data-driven efficiencies, is huge.
The UKHO is actively looking at the role it can play to harness this opportunity, working with other like-minded stakeholders in common purpose.

To help support the development of ‘Just-in-Time’ arrivals, UKHO is working with partners on the Port Call Optimisation Task Force to create a new universal data standard for all parties involved in a port call.
This is a great example of how we can harness the latest innovations in navigational standards to meet shipping and society’s environmental goals.
I’m excited by the contribution we can make to reducing shipping’s carbon emissions, and that’s just one area among many that we are focusing on.

S4S: How can we promote/encourage more innovation in the marine navigation?
What would be the key trends that will cast our attention in the coming years?

P.Sp: One example close to home for the UKHO is the Centre for Seabed Mapping (UK CSM).
The Centre was launched in July to increase the coverage, ‘map the gaps’, improve the quality and access of seabed mapping data collected using public funds, and better promote the role that marine data plays as a critical component of national infrastructure.

We are inviting UK Government organisations involved in seabed mapping, who share common interests in optimising the UK’s national maritime assets, to become a member of the newly unveiled UK CSM.
The idea behind the Centre is to spearhead a coordinated approach to the collection, management, and access of seabed mapping data – and to champion a more integrated marine geospatial sector in the UK.
The UK CSM has established three initial working groups that members can join and contribute to: National Data Collaboration, International Data Collaboration, and Data Collection Standards.
This initiative and other international collaborations that UKHO participates in will help to encourage innovation in the marine data and navigation space.
The role of collaboration in the near-term cannot be understated.
The sector’s challenges are so large that no one player can hope to solve them on their own, so it’s critical we find the right mechanisms – such as the UK CSM – for working together.

S4S: Do you have any other projects/plans you would like to share with industry stakeholders?

P.Sp: To give one example of where things might be heading, the digitalisation of onboard systems, the rapid growth of the Internet of Things, and the improvement in broadband communications have brought the possibility of uncrewed and autonomous vessels within reach.
This will require UKHO to consider how we move from navigational systems that have been simplified to meet the needs of the human user, to navigation solutions that are data-rich and machine-readable.In June, the crewless Mayflower Autonomous Ship arrived in North America after setting sail from Plymouth, UK, three months earlier.
The vessel’s successful voyage – which the UKHO supported with electronic navigational data – demonstrates the power of AI and autonomous technology, and sets the coordinates for where maritime is heading in the near future.

S4S: What is your key message to industry stakeholders with respect to e-navigation?

P.Sp: As the UKHO transitions from paper charts to focusing fully on our ADMIRALTY digital products and services, our core purpose remains the same: supporting the safety of shipping operations and delivering the best possible navigation solutions to achieve that.
Whether for the Royal Navy, commercial vessels or other ocean users, the organisation’s focus is on developing and delivering ADMIRALTY digital services our users need, to promote safe, secure and thriving oceans.

Links : 

Tuesday, October 11, 2022

Is climate change disrupting maritime boundaries?



 Global coral reef distribution (red dots).
Credit: Millennium Coral Reef Mapping Project/World Atlas of Coral Reefs


From Phys by University of Sydney

Coral reef islands and their reefs—found across in the Indo-Pacific—naturally grow and shrink due to complex biological and physical processes that have yet to be fully understood.
Now, climate change is disrupting them further, leading to new uncertainties for legal maritime zones and small island states.

But it may not be time to panic yet.
A number of technologies and new approaches, coupled with expanded research into coral reef island behavior, may help dispel some of the uncertainties and solidify claims.

A study by University of Sydney researchers, published in Environmental Research Letters, finds that the rules for atolls and coral reefs in international law of the sea—already murky and subject to interpretation due to their shifting nature—will be under greater stress as sea levels rise and ocean acidification disrupts reef integrity.

"It's a perfect storm that is bringing instability and uncertainty to what are already difficult boundaries to determine with any great accuracy," said Dr.
Thomas Fellowes, a postdoctoral research associate at the School of Geosciences of the University of Sydney and lead author of the paper.

"There are geopolitical consequences too.
Coral reef islands are the legal basis for many large maritime zones.
Hence, the climate disruptions we're already seeing—and will see in the decades ahead—may have substantial impact not only for small island states, but in hotly contested boundary disputes in places like the South China Sea."

IPCC projections for 2081 to 2100 relative to 1995-2014 under best case scenario (1.5˚C rise, left) and worst case scenario (CO2 emissions double by 2050, right).
Credit: Intergovernmental Panel on Climate Change


This treaty, signed by 167 nations and almost universally recognized, governs everything from territorial seas—up to 12 nautical miles from a coast or low-water line of a reef—to exclusive economic zones of up to 200 nautical miles.
It codifies the rules for freedom of navigation, and allows nations to exploit, conserve and regulate resources in neighboring waters.

"For coral islands, the outer 'low-water line' of the reef is used as the legal baseline to establish maritime zones," said Frances Anggadi, a Ph.D.
student at the University of Sydney Law School.
"The potential loss of maritime zones due to changes in reef baselines from climate change is a serious concern for nations like Kiribati, as well as for larger ones like Australia, who depend on reefs and islands to maintain their claims."

But there is still no clear agreement whether changes to the structural integrity of coral reef islands due to climate will lead to legal vulnerabilities.
"They may not, and that's what many Pacific island countries believe.
What's clear is that a more detailed understanding of coral reef island behavior is needed, along with rethinking of the legal rules."

Dr. Fellowes added that "coral reefs are vulnerable, only thriving within a specific range of biophysical, ocean and climate conditions.
But changes in sedimentation due to climate change may support coral islands and strengthen some maritime claims.
It's not entirely clear that there will only be losers."

Coral reef island shorelines (red) and UNCLOS baselines (orange) at (a) Cocos Keeling Island, Australia (b) Kanton Reef, Kiribati, and (c) Wreck Reef, Australia.
Credit: Geoscience Australia/Sentinel Hub


The researchers argue that one way to buttress existing claims is by defining reef baselines with geographic coordinates like GPS, or remote sensing approaches like satellite bathymetry.

Another is to better understand how climate change will affect island habitability, since sustaining human habitation or economic life in a location is another way to establish a viable claim under the treaty.

But for these approaches to work, more data on each coral reef island system is needed in order to more accurately delineate the true scope of existing claims, how resilient those claims have been so far, and to better understand what aspects of climate change might affect them in the future.

There are four ways in which climate change is disrupting coral reef systems in ways that may affect maritime boundaries: sea-level rise, warming oceans, ocean acidification and increased storminess.

Each has an impact on the interconnected biophysical processes that allow the creation, retreat and overall structural stability of coral reefs and islands.

Cross-section of coral reef geomorphic zones, showing wave energy gradients, sedimentary features (islands, sand aprons and lagoons) and UNCLOS baselines. 
Credit: Vila-Concejo and Kench

For example, higher temperatures trigger the expulsion of algal symbionts in corals and other invertebrates (like giant clams), leading to coral bleaching, which—if enough coral organisms die—can result in reef collapse.
In the decades ahead, this could lead to a shrinkage of the outer low-water line of the reef, reducing the basis for a maritime claim.

Oceans acidify as they absorb more and more carbon dioxide, reducing their mineral saturation and making it harder for corals to form.
Reef building species like Acropora—a small polyp that is common in tropical reefs—begin to change their skeletal structures to rely on less carbonate mineral, imperiling overall reef integrity.

As the reefs grow and expand, they become either fringing, barrier or atoll reefs.
Fringing reefs are the most common, projecting seaward from the shore, forming borders along shorelines and surrounding islands.
Barrier reefs do this at greater distance, separated from land by a lagoon of often deep water.
If a volcanic island sinks below sea level and its reef coral continues to grow, an atoll forms.

Monday, October 10, 2022

Scotland’s defenders of the seas: the volunteers standing up for sea life

At the moment, Scotland is doing a really good job of trashing our insgore waters"
Lauren Smith and Chris Rickard
Photograph : Murdo Macleod/The Guardian

From The Guardian by Karen MvVeigh

An unofficial network of fishers, divers and scientists are banding together to stop illegal fishing and curb coastal destruction


Scotland’s coastal waters are in trouble.
They contain some of the world’s richest and most diverse marine life: bottlenose dolphins, porpoises, minke whales and orcas are among 20 cetacean species found along its coast, while seagrass and kelp forests host otters, octopus, lobsters, sea urchins and squid.

But these waters are vulnerable.
A sobering assessment by the Scottish government in 2020, found that it had failed to meet targets to prevent damage to priority marine environments, causing five large seabed habitats to shrink.
Years of dredging, trawling, anchoring and overfishing are to blame, according to the report, which found that the climate crisis, ocean acidification, storms, disease and pollution from fish farms have also played a part.

As politicians fall short in tackling the accelerating human pressures on the seas, many coastal communities are taking matters into their own hands.

Howard Sargent and Rose Reid: saving marine life from rogue dredgers


At the end of a jetty on Holy Isle, in the Firth of Clyde on Scotland’s west coast, a sign informs visitors the seabed is a protected biodiversity hotspot.

In the clear waters of Lamlash Bay – a ribbon of sea between Holy Isle and the larger Isle of Arran – otters hunt for sea urchins among its kelp beds and maerl, a pink coralline seaweed, carpets the seabeds.
But despite their protected status, these waters are threatened, says Howard Sargent, 56, a former architectural designer who lives on Holy Isle.

Localization with the GeoGarage platform (UKHO raster chart)
 
The sea here was not always so full of life.
By the early 2000s, decades of trawling and dredging for fish had left it close to collapse.
Sargent traces the problems back to the government’s decision in the 1980s to allow trawlers to fish closer to the coastline.
“It’s the ‘tragedy of the commons’ – if it’s a free-for-all, everyone takes everything before anyone else can,” he says.

Residents intervened and in 2008, after a campaign, Lamlash Bay was designated a “no-take zone” – banning damaging fishing practices.

Since then, the waters have seen a dramatic revival.
Lobsters are now four times as abundant and scallop density is four times higher.
But rogue fishing vessels still seek to dredge the seabed for prawns and scallops.

Sargent and his partner, Rose Reid, 39, are part of an unofficial network of coastal defenders.
“We keep an eye out for dubious fishing activities,” says Sargent.

Howard Sargent and Rose Reid at Lamlash Bay.
Photograph: Murdo MacLeod/The Guardian


He reports any potentially illegal fishing to Marine Scotland, the branch of government regulating Scotland’s seas and fisheries, but it is hard to secure convictions without solid proof, as vessels are allowed to transit through no-take zones.

In March 2019, Sargent spotted a trawler dragging nets through the bay early in the morning.
He grabbed his camera and managed to get photographic evidence.
“It had big nets out the back and there were seagulls overhead,” says Reid, a psychologist.

They were due to give evidence against the vessel in court but at the last minute, the skipper pleaded guilty to having fishing gear deployed and was fined £2,200.

Campaigners called the fine “paltry” – the maximum penalty is £50,000 – and the couple were disappointed the prosecution was stopped.
But Sargent believes the case is a deterrent: “Local fishing boats are now aware that Lamlash Bay is well monitored.”

A spokesperson for Marine Scotland says it assesses all reports of suspected breaches of marine protected area (MPA) regulations and, where possible, deploys a compliance vessel to gather evidence and detain suspect boats.
It is also “rolling out tracking and remote electronic monitoring across the inshore fleet”.

 
Lauren Smith and Chris Rickard, at the Needle’s Eye in Macduff.
Photograph: Murdo MacLeod/The Guardian

Chris Rickard and Lauren Smith: fighting to save the ‘manta ray of the north’

Three years ago, Chris Rickard became one of the few people in Britain to have seen a flapper skate in the wild.
He spotted the elusive, critically endangered animal on a dive in the Summer Isles in the Scottish Highlands.

“I was struck by how something so massive and majestic could be so unknown in our waters,” says Rickard, a marine conservation consultant and keen diver, who lives near Macduff in Aberdeenshire.

The world’s largest skate, sometimes known as the “manta ray of the north”, flapper skates can reach up to three metres in length, with a wingspan of 2.5 metres.
The giant predator, once common in British waters, is so rare that it has been described as extinct in large parts of its former range due to overfishing; the north-west coast of Scotland is one of its last strongholds.

A few weeks after his sighting, Rickard, 45, saw on social media that a mermaid’s purse – the egg case of skates – had been found by a scallop dive boat on Scotland’s west coast.
He persuaded the boat’s skipper to take him to where it was found – the cold, dark waters of the Inner Sound of Skye, near the uninhabited island of Longay.

They dived more than 30 metres below the surface, where Rickard shone his torch through the gloom: “Suddenly I spotted a couple of purses.” By the end of the dive he had counted 40.
“I knew they were alive, as I could see embryos wriggling inside some of them.”

Localization with the GeoGarage platform (UKHO raster chart)

On surfacing, he texted Lauren Smith, a friend and marine biologist who runs Saltwater Life, a shark research and conservation NGO.
“This was really something,” says Smith, 39.

But live eggs, lying unprotected near scallop grounds, could be wiped out in seconds by dredgers.
Rickard contacted Marine Scotland but no protection was put in place.

Returning to the site in 2020 with Smith and others, they found more than 100 egg cases – the largest known flapper skate egg-laying site in the world.
With the help of Our Seas, an alliance of groups supporting sustainable seas, and Blue Marine Foundation, they publicised the find and called on the Scottish government to take action.

In March 2021, the government designated the site “the Red Rocks and Longay urgent marine protected area” and banned all fishing.
It is now deciding on permanent protection measures.

Smith and Rickard would like to see more of Scotland’s waters protected from trawling.
“At the moment, Scotland is doing a really good job of trashing our inshore waters,” Rickard says.

A Scottish government spokesperson said 37% of Scottish waters were MPAs and it was committed to increasing protections, including through new highly protected marine areas.
These will cover at least 10% of Scottish waters by 2026, “prohibiting all extractive, destructive and depositional activities”.

John Aitchison at the Sound of Jura, with his spotting telescope.
Photograph: Murdo MacLeod/The Guardian

John Aitchison: halting a fish farm in a protected area


John Aitchison, a wildlife cameraman, director and producer, has travelled to some of the world’s most remote places for films including the BBC’s Frozen Planet, to witness the wildlife crisis at first-hand.

But it was back home, in Mid-Argyll, that he decided to take action.
A few weeks before Christmas 2016, he discovered plans for an industrial-sized fish farm off the Sound of Jura, a designated MPA.

The company behind the farm planned to site a dozen 100-metre circular cages capable of housing 1 million rainbow trout, just off the coast at Dounie.
Nearly everyone thought the site was inappropriate, Aitchison, 56, says.
“It felt like a juggernaut coming towards us.”

Kames Fish Farming argued its farm would be built and operated responsibly and would create local jobs.
The community argued that pesticide discharge, sea lice and fish escaping from the farm would threaten the environment and wild salmon.

Localization with the GeoGarage platform (UKHO raster chart)
 
Aitchison, chair of the Friends of the Sound of Jura, had to take a crash course in licensing and planning law: they only had 28 days to oppose the granting of a licence by the Scottish Environment Protection Agency.
More than 3,000 people signed a petition against the plans, more than a third from Argyll’s villages and hamlets.

It was a frustrating process, says Aitchison.
But they got a lucky break.
A seabed survey found northern sea fans, some of Scotland’s rarest sea life, close to the proposed site.
In December 2017, Kames Fish Farm withdrew its application.
“Although we succeeded, it left us realising how difficult it is to influence that type of decision.
In Scotland, planning rules favour developers and they favour salmon farming,” Aitchison says.

A spokesperson for the Scottish Environment Protection Agency said itlistens to those who share an interest in Scotland’s water environment before it authorises a development.

David Nairn, right, with David and Jean Ainsley.
There is a salmon farm in the background.
Photograph: Murdo MacLeod/The Guardian

David Nairn and David Ainsley: protecting porpoises from noise pollution


Five years ago, David Nairn, a skipper and conservationist, was watching porpoises on his cruiser in the Firth of Clyde, the deepest coastal waters in the UK, when he noticed something amiss.

“We’d been surveying them, zigzagging up the Clyde,” says Nairn, 50, who records underwater noise, identifying the mammals – a protected species in Scottish waters – by their high pitched clicks.
“But when I passed fish farms, there were none.”

Later analysis revealed a “horrendous noise”, says Nairn, founder of Clyde Porpoise.
It was an acoustic deterrent device (ADD) used to scare off seals that attack fish-farm cages.

Porpoises, which are not a threat to fish farms, “are really affected by high-frequency noise”, says Nairn, who estimates as many as 2,500 live in the Clyde during the calving season.

Localization with the GeoGarage platform (UKHO raster chart)
 
Farther up the west coast, a marine biologist working in wildlife tourism was also convinced that acoustic deterrents were driving cetaceans away.
“My life is out at sea, watching for porpoises, dolphins and whales,” says David Ainsley, a former creel skipper who runs Sealife Adventure, a wildlife tourism company in Seil Island, with his wife, Jean.

They say the difference between areas with salmon farms and those with none is like “chalk and cheese”.
“If you damage the hearing of an echo-locating animal, it can die because it can’t find food,” he says.

Nairn and Ainsley, who met through the Coastal Communities Network, an alliance of grassroot groups in Scotland, began working together to tackle the problem.

They knew that, under Scottish law, fish farms using acoustic deterrents need a licence, unless they can demonstrate that the devices do not disturb cetaceans.
They also knew that by 2018, about 90% of Scottish fish farms were using them.
If you damage the hearing of an echo-locating animal, it can die because it can’t find food David Ainsley

Despite the licence requirement, Nairn and Ainsley discovered that Marine Scotland did not hold any information about how many acoustic deterrent devices were used in fish farms.

They argued – via petitions, parliamentary questions and using acoustic evidence – that the Scottish government should enforce existing law.
During this time, deterrent use dropped off dramatically.

In November last year, the pair enlisted Guy Linley-Adams, an environmental solicitor, who made a formal complaint to the independent regulator, Environmental Standards Scotland (ESS), accusing Marine Scotland of failing to ensure fish farms were complying with the regulations.

In August, ESS published a report recommending improvements in the Scottish government’s “compliance process”, which it says have since been implemented.
Linley-Adams described this as a “de facto ban” on acoustic devices in salmon farming, because it would be “impossible” to prove the use of the device would not disturb cetaceans, or for the industry to successfully apply for a licence, especially as effective alternatives such as seal nets are available.

The Scottish government told the Guardian it welcomed the ESS report and said fish farmers must obtain any relevant consent or demonstrate that acoustic devices “will not harm marine mammals’”.
Salmon Scotland, which represents the salmon farming industry, said no devices were currently in use in Scottish farms.“There is no ‘victory’ or ‘de facto ban’,” a spokesman said.

Theo Bennison prepares to deploy a remotely operated underwater vehicle from the Sea Beaver in Oban.
Photograph: Murdo MacLeod/The Guardian

Theo Bennison: mapping life on the seafloor

Marine ecologist Theo Bennison has spent the past five months on the Sea Beaver, a boat travelling around the Scottish coast to measure the health of the seas.

Operation Ocean Witness, run by Greenpeace and the Scottish charity Open Seas, relies on networks of local communities to report on threats including illegal fishing in MPAs.

In June, sources led them to Orkney, where they found dredging damage to maerl beds, which take decades to grow and act as a nursery for invertebrates and fish.
 
Localization with the GeoGarage platform (UKHO raster chart)

“It is shocking that damage like trawling and dredging is allowed to happen in protected areas,” says Bennison, 28, a researcher with Open Seas.
“The government said it was going to protect biogenic reefs, which maerl beds are, and the fact that this has happened is pretty worrying.”

Open Seas will report its findings to Marine Scotland.

By using drone footage, Bennison and the team also helped produce the first map of an important seagrass meadow off Papa Westray, measuring 30 hectares (74 acres) in total.

There are already five fish farms in the area, says Bennison.
“Hopefully, it will help the community in their battle against a new proposal for another fish farm.”
 


Sunday, October 9, 2022

Killer whales eating white sharks in Mossel Bay, South Africa


[adapted from official press release]
The first direct evidence of orcas killing white sharks in South Africa has been captured by both a helicopter and drone pilot, and a new paper published today in The Ecological Society of America’s journal Ecology presents both sets of video footage, which provide new evidence that orcas are capable of pursuing, capturing and incapacitating white sharks.
One predation event was filmed on drone, but the researchers believe that three other sharks may also have been killed.
While a clip of the drone footage was aired in June on #DiscoveryChannel this was only part of an hour-long hunt of multiple sharks, as revealed by the exclusive helicopter footage.
The new paper offers more extensive footage, along with data from tags, drone surveys and shark-tour boats showing that white sharks fled from the Mossel Bay region of South Africa for several weeks.
Orcas have been observed preying on other shark species, but direct observation of predation on white sharks locally has been lacking – until now.
“This behavior has never been witnessed in detail before, and certainly never from the air,” said lead author Alison Towner, a senior shark scientist at Marine Dynamics Academy in Gansbaai, South Africa.
Only two killer whales in South Africa have been previously linked to hunting white sharks, but never actually seen ‘in action’.
Only one of those animals was observed in the new footage, along with four other killer whales.
The authors believe that the involvement of these four new whales suggests the behavior may be spreading.
The study also gives new insights into sharks’ attempts to evade capture by orcas.
On two occasions, orcas approached sharks closely and slowly, while the shark, instead of fleeing, stayed close to the orca, keeping it in view – a common strategy that seals and turtles use to evade sharks.
However, orcas are social and hunt in groups, and the researchers believe these behaviors may render the circling strategy ineffective for white sharks.
“Killer whales are highly intelligent and social animals.
Their group hunting methods make them incredibly effective predators,” said marine mammal specialist and study co-author Dr Simon Elwen, Director of Sea Search and a research associate at Stellenbosch University.
The study confirmed that one infamous killer whale, locally known as “Starboard,” was part of the pod and ate what was suspected to be a large piece of shark liver at the ocean surface.
The novel footage also revealed how another killer whale bit into a white shark at the region of the liver.
“I first saw Starboard in 2015 when he and his close-associated ‘Port’ were linked to killing seven gill sharks in False Bay.
We saw them kill a bronze whaler [copper shark] in 2019 – but this new observation is really something else,” said David Hurwitz, a boat-based whale-watching operator from Simon’s Town Boat Company.
The new study also analyzed drone and cage dive boat survey data before and after these predation events.
White sharks were seen on every survey day for the weeks prior to the predation event and multiple sharks were seen on the day of the predations.
However, only a single white shark was seen in the 45 days after the predations, confirming a flight response by sharks.
“We first observed the flight responses of seven gills and white sharks to the presence of killer whales Port and Starboard in False Bay in 2015 and 2017.
The sharks ultimately abandoned former key habitats, which has had significant knock-on effects for both the ecosystem and shark-related tourism,” said South African National Parks’ shark expert and marine biologist, Dr Alison Kock.
Previous studies have documented how new behaviors spread among killer whales over time through cultural transmission.
The authors suggest that if more killer whales adopt the practice of hunting white sharks, then the behavior will have far wider impacts on shark populations.