Tuesday, September 11, 2018

Ocean Cleanup : A 600-meter-long plastic catcher heads to sea, but scientists are skeptical

On September 8, the world’s first ocean cleanup system was launched from an assembly yard in Alameda, through the San Francisco Bay, toward the infamous Great Pacific Garbage Patch.
Watch the deployment live.

From Wired by Matt Simon

A project of staggering ambition will sail past San Francisco and out to sea through the Golden Gate.
The invention of an organization called the Ocean Cleanup, it consists of a 600-meter-long plastic tube with a dangling screen that a ship will tow 240 nautical miles out to sea for testing.
If that pans out, it’ll head another 1,000 miles out to the Great Pacific Garbage Patch, where the U-shaped system will autonomously gather floating plastic for a vessel to come along and scoop up every six weeks or so, like a garbage truck.
The Ocean Cleanup says it aims to cut the amount of plastic in the patch in half in five years.


The oceans have a major plastic problem—over 5 trillion pieces of plastic taint the seas, and the Garbage Patch is only growing.
Accordingly, Ocean Cleanup has raised $40 million from donors and companies.
But many scientists don’t think Ocean Cleanup’s plan holds water.
In June, Southern Fried Science, a marine science website, did a survey of 15 ocean-plastic pollution experts.
More than half had serious concerns about the project, and a quarter thought it was just a bad idea.


“It's certainly ambitious,” oceanographer Kim Martini, who has studied the Ocean Cleanup campaign, tells WIRED.
“It oversimplifies a very complicated problem that people have thought a lot about.”

Credit: Benjamin Von Wong/The Ocean Cleanup

One issue is that we don’t yet know how ocean plastic is distributed in the water column.
“The fact is, a lot of plastic isn't at the surface,” Martini s ays.
“There's a lot of research showing that it's sinking.” A plastic bottle, for instance, will fill with water and sink to the seafloor.
And tiny bits of degraded plastic can swirl up and down the water column.
The free-floating Ocean Cleanup system may well snag the bits at the surface, but with a screen made of woven polyurethane that hangs down 3 meters at its lengthiest, it’s limited in what it can reach.


“There's also the fact that you're collecting and aggregating plastics, and so that's actually going to attract more animals to it,” says Martini.
“All this marine debris, things rest on it, things like to grow on it—it's kind of a marine desert out there.
It's amazing what a fish will do for a little bit of shade.”

 The 'Wilson' project aims to collect plastic debris from the Great pacific garbage Patch
courtesy of Guardian graphic (source : the Ocean Cleanup)

Another concern is that organisms such as bacteria and algae will start to grow on the device itself, which could increase drag and the weight of the structure and potentially change how the dangling screens behave.
Ocean Cleanup, though, says it designed the system to be as smooth as possible, to discourage such growth.
And while the organization admits the device might attract curious sea life, it insists the system poses no threat.
“We designed the system such that there is basically no risk of entanglement,” says Arjen Tjallema, technology manager at Ocean Cleanup.
“So if a fish or a whale or another animal would come close to the system, then it’s relatively harmless.” Yet rogue fishing nets—which Ocean Cleanup’s research says make up perhaps half of the trash mass in the Great Pacific Garbage Patch—could float into the piping, get stuck, and ensnare turtles and other ocean life.
Still, doing nothing about the plastic problem isn’t helping marine life either.

The Great Pacific Garbage Patch (GPGP) contains at least 80,000 tonnes of plastic floating inside an area of 1.6m square kilometres
image : Scientific Reports, Lebreton et al

Then there’s the issue of the open ocean beating the hell out of the system and turning it into part of the problem it’s trying to solve.
Because the tube, after all, is made of 600 meters of plastic.
Even UV light may be a problem, as it can bombard plastic and cause it to shed tiny bits.
Ocean Cleanup, though, says its high-density polyethylene plastic can reflect UV radiation.
“I sort of wonder what kinds of microplastics this thing is going to be generating on its own, assuming that it's even functioning exactly as designed,” says oceanographer Kara Lavender Law of the Sea Education Association.
Worse yet, the thing could snap in a storm.
“If it's shedding nano-size particles and then gets smashed into 200-meter-long pieces, you're really covering the whole size range there.”

Ocean Cleanup says it has done hundreds of scale model tests of the system and tested prototypes in the North Sea.
It adds that the system is designed to weather the waves of a once-in-a-century storm.
If the device happens to wander out of the Great Pacific Garbage Patch gyre, Ocean Cleanup says it will dispatch a boat to tow it back into place.

Given the concerns about Ocean Cleanup’s plan, Law wonders whether it might not be better for (lowercase) ocean cleanups to tackle other, safer targets.
“Why not focus your efforts much closer to rivers or places we suspect most of this debris is originating?” she suggests.

This is the approach taken by the Waterfront Partnership of Baltimore.
It has deployed giant trash wheels complete with googly eyes known as … Mr. Trash Wheel and Professor Trash Wheel, which use the river’s own current to power a wheel that lifts trash out of the water and into a dumpster barge.
(If the river is running too slowly, solar power kicks in to get the wheel going.) Together, the devices have pulled 900 tons of trash from the waters around Baltimore.



The ocean is big. Cleaning up the Great Pacific Garbage Patch using conventional methods - vessels and nets - would take thousands of years and tens of billions of dollars to complete.
Our passive systems are estimated to remove half the Great Pacific Garbage patch in just five years, and at a fraction of the cost.
Our first cleanup system will be deployed in the summer of 2018.
This is how it works.

Ocean Cleanup’s plan is more ambitious.
If the first system checks out over the next few weeks, it’ll head farther out to sea to get to work.
The end goal? Sixty giant pipes floating out there.
“It's a grand experiment that they're conducting,” Law says.
“It would not be my first choice for an intervention, especially out in the middle of the ocean, but we'll see what happens.”

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Monday, September 10, 2018

Maritime Traffic Alert and Collision Avoidance System MTCAS


As maritime commercial and recreational traffic increase, accidents become more likely to happen.
To prevent collisions at sea, researchers of the MTCAS project are now making use of a technology originally used in aviation.
MTCAS stands for Maritime Traffic Alert and Collision Avoidance System.
While standard systems only depend on currently observable ship data such as location, direction and speed, the MTCAS algorithm also integrates historical tracking data, planned routes, knowledge bases, external information, an environmental database and navigators in the decision making.
This allows for a dependent, precise warning and clear, misunderstanding free manoeuvres.
Want to learn more about the project?
Visit the following website: OFFIS

From Mycoordinates by Christian Denker & Axel Hahn

The history has shown a continuous increase in year to year accidents at sea.
In the near future, higher traffic density is estimated, which contributes to this increase.
Within the 3-year Project MTCAS, 5 German partners from industry and academia contribute to accident reduction by developing an e-Navigation Assistance System for pro-active, predictive and cooperative collision avoidance.


MTCAS is the abbreviation for Maritime Traffic Alert and Collision Avoidance System, which implies the basic idea of adopting the Airborne Collision Avoidance System (ACAS) implementation TCAS.
However, MTCAS broadens its bounds by assisting the ships’ crew in conflict detection and conflict resolution under consideration of a ships holistic environment.
Concrete examples include regularities, bathometry, non-equipped vessels and VTS, which are elaborated in this paper.
Dissident from TCAS, MTCAS does not automatically intervene in terms of issuing steering commands, but supports seafarers in cooperatively finding safe and efficient trajectories, whose onboard implementation avoids collisions.

This paper informs about the activities in the MTCAS project.
We welcome constructive thought and feedback to foster synergies amongst our domain.


Introduction

Continuous increasing accident risk drives the need for a Maritime Traffic Alert and Collision Avoidance System (MTCAS).
As broadly known, “around 90% of world trading is carried out by the shipping industry” (Chauvin, Lardjane, Morel, Clostermann, & Langard, 2013) the shipping industry has implemented a number of measures aimed at improving its safety level (such as new regulations or new forms of team training and thus shipping can tip the scales of our world’s economy.
The ongoing trend towards an increasing size of new builds, in terms of capacities for cargo and passengers seems to contribute to the magnitude of accident risk: A correlation to an increase in maritime accidents can be perceived from current accident statistics.
Whereas collisions is solely one of six categories in the EMSA accident statistic, at least samples from the categories contacts and groundings, such as beaching, can be accounted to accident preventive actions.



 EMSA overview of maritime casualties between 2011 and 2015.

Nowadays Collision Avoidance Means

Collision avoidance is a major process on a ship bridge and in Vessel Traffic Services (VTS), where officers, pilots and operators strive towards efficiency and safety of maritime transport.
Therefore classical navigational means are used, which are briefly introduced in this section.

Automatic Radar Plotting Aid (ARPA)

ARPA is a plotting aid, whose functionality includes detection and tracking of foreign vessels.
On modern INS bridges it may be integrated into ECDIS.
For collision avoidance it provides restricted movement predictions, which are based solely on CPA/TCPA, which imply a constant velocity approach.

Automatic Identification System (AIS)

AIS is a radio system for exchanging navigational and ship data in-between ships and as a means for shore-side surveillance via a VTS-System.
Since enactment of SOLAS continuously commercial fleets have been equipped with this technology, to continuously interchange static and dynamic passage data.
Non-obtrusive shortcomings of AIS are potential misuse through users’ key errors and lag of security, such that the integrity, confidentiality and availability of data is not given.

Maritime Mobile Service (MMS)

MMS is according to ITU a “mobile service between coast stations and ship stations, or between ship stations, or between associated on-board communication stations; survival craft stations and emergency position-indicating radio beacon stations …” (ITU, 2012).
The inter-stations communication via voice bears the risk of imprecise situation forwarding amongst participants, since English is the second language for many and language barriers may displayable conveying crucial information.

Related Work

MTCAS incorporates technologies, which are part of the current state of the art in ship dynamics modelling, trajectory planning, VTS technologies and modern positioning, navigation and timing (PNT).

Ship Dynamics Modelling

Physical characteristics of a ship limit its manoeuvrability.
Ship characteristics, such as hull form, size, and propeller/ engine, effect with environment conditions, such as water/waves and air/wind.
Both, ship characteristics and environment conditions are part of modern mathematic models for dynamic manoeuvrability calculation.
Model results can be facilitated in trajectory planning.
(Benedict, Kirchhoff, Gluch, Fischer, & Baldauf, 2009)

Trajectory Planning

On a strategic level waypoint planning is part of every voyage plan, which is typically settled pre-departure.
On an operational level ships’ crew executes manoeuvers by adjusting the helm or autopilot, to start a turn.
On the tactical level, decisions are made, that implement the strategy on the operational level.
This is where manoeuvrability and environment can have leverage on operational performance on safety and efficiency.
With evolutionary algorithms, behavioural leaning approaches and/ or neural networks trajectories can be found, which consider ship and environment.
With these techniques, single ship optimal solutions can be found.
To find a global optimum n-trajectory negotiation approaches have recently been developed (Hornauer & Hahn, 2013).

VTS Technologies

Detection of deviations from anticipated behaviour is implemented in modern VTS-Systems.
The project EfficienSea, and its successors, advance in the area of centralized concepts for sea traffic management.
Times of VTS’s sole availability via MMS will soon be surpassed.
With ongoing activities such as the project COSINUS, VTS-Systems are integrated into automated route exchange amongst ships via a data link.

Resilient Positioning, Navigation and Timing (PNT)

To exchange trajectories for proficient collision avoidance, instead of routes, precise data is required.
This is not given in nowadays systems, where GPS may induce standard deviation error in positioning and GNSS may negatively influence common timing through interferences.
Resilient PNT encounters these disadvantages with sensor data fusion, which has been demonstrated in project ACCSEAS and MonaLisa.

Whenever collision avoidance as a safety of life critical application should be based on absolute positioning, then the question arises, how resilient provision of PNT data can be achieved onboard a vessel.
Due to the vulnerability of GNSS with respect to ionospheric disturbances, jamming and spoofing the joint usage of other systems (terrestrial backup systems) and other onboard sensors is considered.
Vulnerability encountering backup systems like e-LORAN, R-Mode or absolute RADAR positioning have been evaluated and proposed (Ziebold et al., 2010), (IMO, 2012).
Onboard a vessel a sensor fusion algorithm is responsible for the PNT data provision.
All available Position, Velocity and Timing (PVT) and Navigation data, from onboard sensors in order to provide optimal PNT output data, is integrated.
Asides optimal estimations of the PNT output data, also integrity information is provided, based on accuracy estimations.

A new COLREG-compliant collision avoidance system developed by the MTCAS project in its first demonstration test in Germany in Wilhelmshaven on September 6th, 2017.

 THE MTCAS Approach

MTCAS assists in collision avoidance by warning the crew before critical situations develop and recommends evasive manoeuvres for conflicting ships.
Dissident from TCAS, MTCAS does not automatically intervene in terms of issuing steering commands, such that it can be seamlessly integrated into nowadays (legally regulated) operations on-board of a ship.
Meanwhile, MTCAS supports seafarers in cooperatively finding safe and efficient trajectories, whose on-board implementation (solely by seafarers) avoids collisions.

MTCAS will be developed on the basis of required equipment and advanced sensor technologies.
Further, within the project, organizational processes around MTCAS are developed and tested, considering responsibilities and interaction of people on board and in VTS.

The development of MTCAS is based on four core concepts:

Improved Situational Awareness

An essential contribution of MTCAS is enhancing safety and efficiency, by increasing situational awareness about critical traffic situations.
A starting point for MTCAS is the route exchange technology, which has been developed in the COSINUS project, enhancing harmonized situational awareness aboard and ashore.
MTCAS integrates this technology for conflict detection and evasion.
To gain required operational precision the technology will be extended with improved integrity monitoring and exchange of ship dynamics.
Additionally, MTCAS is collecting information about the environment from heterogeneous data sources.
The more information is available, the better is the situation assessment.
When the situation is evaluated, MTCAS will provide the result to the captain and ask for a confirmation.
That happens on all related ships.
MTCAS will submit the confirmation of the captain to all off the other ships.
Therefore, all captains are aware of the situation and know that the others are as well.
MTCAS ensures all captains have the same information about the situation and prevents misunderstandings.

Context-sensitive Prediction

Depending on the current traffic situation and under consideration of ship dynamics as well as information on the route and past motions of the own ship MTCAS predicts ship movements and short term traffic progression.
This incorporates for instance intention prediction, topology of water ways, bathymetry, ships’ destination, rules and regulations and VTS information.
This prediction leads to an enhanced alarm management.
Due to the prediction false alarms are suppressed or corrected.
This decentralized calculation of traffic and manoeuvre predictions (on each ship) is exchanged (Ship2Ship2Shore) and commonly coordinated/adjusted.
Thus a local overview of the situation is enriched to a complete traffic situation overview over time.

 Testing MTCAS (2018 February)

Decentralized automatic negotiation of evasive manoeuvres

MTCAS aims at on-board and ashore working decentralized conflict detection and at safe and efficient conflict resolution in critical situations.
Ships’ masters agree jointly on a set of evasive trajectories.

Monte Carlo simulation to analyze the risk of incorrect collision detection

 Situation awareness is improved through route exchange and context, which improves the prediction of ship movements.
Where today systems would trigger three alarms (left), the context sensitivity of MTCAS allows a detailed operational picture of driving situations (right).

A set of evasive trajectories is therefore always suggested to all ships’ masters, which has to be accepted of declined.
MTCAS will guarantee that evasive trajectories are found within real-time and that the crew can always be aware of and integrated in the conflict resolution process.
Within the project MTCAS’ safety will be proven with qualitative and quantitative means, to secure a gain towards maritime safety.

The two mayor benefits from this project are improved predictive situation awareness and to reduce misunderstandings my supporting the seafarer in consistent situation assessment and evasive manoeuvre planning.

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Sunday, September 9, 2018

Ancient world maps

Waldseemuller’s 2nd world map (1516) by which he had abandoned Ptolemy’s classical map projection and used newly available information provided by Portuguese a.o. explorers.

 
Lorenz Fries Map of the World (1522 / 1535)

 French map (1547)

 Ali Macar Reis map (1567) (Ottoman Archives, Turkey)
 
Bertelli / Forlani 1568 World Map ("Vniversale Descrittione Di Tvtta La Terra Conoscivta Fin Qvi") based on an earlier Gastaldi map

 Mercator world map (1569)

Portulan portuguese map of the world by Domingos Teixeira (1573)

Jodocus Hondius' Map of the World - 1595

 Atlas sive Cosmographicae Meditationes de Fabrica Mundi et Fabricati Fugura (1596)
author : Gerardus Mercator (source : Rarebookroom)
 
1596 Magini Map of the World after Mercator 

"A Map of the Myriad Countries of the World" (坤輿萬國全圖), 1602
The First Chinese World Map (Japanese copy, 1604)

 Wanguo Quantu or Complete Map of the Myriad Countries (1620s)

Double-hemisphere map of the world (1651)

Hemisphere map of the World by Dutch publisher Joachim Bormeester (1685)

Samuel Thornton sea atlas (circa 1702 - 1707)
Title reads: " The new and correct Mapp of the WORLD according to Mercador's projection"
A large sea-chart of the world on Mercator's Projection.
It depicts California as an island, and shows the Mississippi and the Great Lakes in North America which was at the time the newest updates in world cartography.
Thornton also provided great details in the sea trade winds, the time of the year they flow, as well as seasonal monsoons.
The map also reveals the routes of such great maritime explorers as
- Abel Tasman: a Dutch explorer who discovered Tasmania to which he gave his name, New Zealand, and the Fiji Islands.
- William Dampier: The first English explorer to explore part of Australia and the first person to circumnavigate the world three times.
- Edmund Halley: English astronomer and geophysicist who is famous for successfully calculating the orbit of the comet now known as Halley's Comet. 


 An attractive first edition first state example of Jacques Nicolas Bellin’s 1778 nautical chart of the world.
Presents the entire world on a Mercator Projection based on a Paris (L’Isle de Fer) meridian.
This is notably the first state of this important map, exhibiting a pre-Cook geography throughout, but most specifically in the Pacific and along the northwest coast of America.
North America to the west of the Mississippi is vaguely rendered according to 16th century expeditions into the region by Coronado, La Salle, De Soto, and others.
Bellin identifies the semi-mythical civilizations of Quivira and Teguayo, both associated with legends of the Seven Cities of Gold, in what is modern day Utah, California, and Nevada.
Along the western coast the strait discovered by Martin Aguilar is noted.
Further north still the River of the West (Fl. de l’Ouest) extends from the west coast to the Lake of the Woods (Lac de Bois) and thence via additional waterways to the Great Lakes and the Atlantic.
The River of the West appeared in many 18th century maps of the Americas and is reflective of French hopes for a water route from their colonies in Canada and Louisiana to the Pacific.
Still further north the coastline becomes extremely vague, in places vanishing altogether.
The Aleutians are vaguely rendered according to various sightings by Vitus Jonassen Bering and Aleksei Chirikov in the 1740s and identified as the “Archipel de Nord”.
 In the Pacific, various Polynesian Island groups are noted though many are slightly or significantly misplaced.
The Solomon Islands are vastly oversized referencing the early 17th claims of Quiros.
The other lands discovered and erroneously mapped by Quiros in 1606 and Davis in 1686 during their search of the great southern continent are also noted.
Hawaii, as yet undiscovered, is absent. New Zealand is rendered twice though is accurate in its form and position. Australia, here labeled “Nouvelle Holland”, has part of its southern coastline ghosted in and Van Diemen’s Land (Tasmania) is attached to the mainland.
The southern coast of New Guinea is similarly ghosted in, suggesting its unexplored state.
It is of interest that there is a common misconception regarding this map that suggests the first edition was dated 1748.
There are editions with a printed date of 1748, but these are actually later editions.
The 1748 date is a printing error in which “8” and “4” are transposed, the actual date of publication being 1784.
The first edition of this map is the 1778 example shown here. 
 
1744 Bowen Map of the World on Mercator Projection (Sea of Korea identified) 
 
1801 Map of the World on Mercator Projection by John Cary.
Designed to illustrate the explorations of the previous century
 A New Chart of the World, on Mercator's Projection:
Exhibiting the Track & Discoveries of themost Eminent Navigators, to the Present Period.
Details the entire world as it was known at the turn of the 19th century.
Displays the continents in considerable detail but offers only minimal information in the Arctic and Antarctic latitudes.
Designed to illustrate the explorations of the previous century, focusing specifically on the important explorations of Cook, Vancouver, Perouse, and Gores.
Offers copious notations on explorations and unconfirmed discoveries throughout.
Prepared in 1801 by John Cary for issue in his magnificent 1808 New Universal Atlas.
 
1855 World Map from Qing Dynasty

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Saturday, September 8, 2018

Fuocoammare, par-delà Lampedusa

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Friday, September 7, 2018

150 years of shifting global fishing

Prior to major advances in fisheries technologies, such as trawl nets, steamships, and radar, annual catches of fish were measured in kilograms.
Today, regional catches can number in the tens of thousands of tonnes per year 
picture : Mevagissey Luggers heading out to sea from an old post card


From Hakai Magazine by Gemma Conroy

A new data set shows how marine fishing has changed over time.

For thousands of years, seafood has sustained communities, livelihoods, and economies across the world.
In ancient Rome, wealthy entrepreneurs snapped up beachfront property and built elaborate fish farms.
In 15th-century Chile, coastal people bartered shellfish for inland resources.
The Vikings living on Norway’s Lofoten Islands were fierce and powerful raiders, but they were also prodigious fishers of Atlantic cod.
Over millennia, shifts in politics and changing technology have drastically altered when and where people go to fish.
But accurate scientific records of this vast history of fishing activity capture, at best, a tiny sliver of the whole.

Most scientific studies of global fishing patterns only extend back to the 1950s, when groups such as the United Nations Food and Agriculture Organization began keeping detailed records.
Today, these mid-century records are used as the baseline against which modern fisheries data is compared when making decisions about fisheries management and marine conservation.
But Reg Watson, a fisheries ecologist at the University of Tasmania, was unsatisfied with this truncated view of history.

Over the past 150 years, global fishing activity has been concentrated in hotspots.
Advances in navigational, shipping, and storage technologies have enabled fishing vessels to spread out around the globe, while changes in politics and economics have shifted the locations of peak fishing activity.
Illustration by Watson and Tidd

In a new research effort, Watson and his colleague Alex Tidd, a fisheries scientist at the Galway-Mayo Institute of Technology in Ireland, scoured online databases, regional management records, vessel-tracking satellites, and historical records dating back to 1869 to produce the first comprehensive maps of global marine fishing over the past 150 years.

The study doesn’t account for the full history of fishing, of course, but it does reveal detailed patterns of fishing across countries, including differences in catch composition and fishing gear, for a much bigger period of history than previous records.
Watson and Tidd’s reconstructed records also estimated the rates of illegal, unreported, and discarded catch.

Watson says examining fishing trends over such a long period offers a glimpse of how fishing has changed marine biodiversity.
Looking back in time gives researchers a clearer idea of historical fish populations before they were heavily exploited by modern industrial fishing.
This information can be used to assess the sustainability of modern fishing activity.
“It’s like playing a detective game,” says Watson.
“There’s a lot you can do with these maps, from figuring out greenhouse gas emissions produced by fleets to seeing how fishing impacts wildlife.”

Fisheries ecologist Chris Wilcox was not involved in the research effort but is already putting Watson’s findings to use.
Wilcox’s team at the Australian government’s Commonwealth Scientific and Industrial Research Organisation is using the data to investigate the link between fishing activity and seal entanglement.
By examining fishing levels in regions where there are seal colonies, the researchers will be able to gauge whether discarded fishing gear is the main cause of seal entanglement.

Many organizations, such as Global Fishing Watch, keep an eye on large-scale commercial fishing.
But Wilcox says Watson’s maps reconstruct the difficult aspects, such as how much smaller vessels caught or the amount of illegal catch.
“It has a lot of value for people who are trying to understand how fisheries are depleting ecosystems,” explains Wilcox.

Overfishing
Christian Åslund Photography 

The findings show that before 1900, the United States, Canada, and Japan had the most active fisheries.
Even still, landings were recorded in kilograms, not tonnes, and the majority of fish were bottom-dwellers and small pelagic species.
After the turn of the century, the United Kingdom caught up, with recorded landings peaking in the 1930s and 1940s.

Technological change spurred a new era of offshore fishing in the first half of the 20th century as sails and oars were replaced with diesel and steam, enabling vessels to travel farther and withstand stormy seas.

While the Second World War slowed fisheries expansion, the industry rebounded to full force during the 1950s economic boom.
The world’s first freezer trawler, the Fair Try, was launched in 1953 and paved the way for more distant voyages and global trading.
Fleets began to trawl the seafloor and undertook long voyages to catch tuna, squid, and shrimp.
Some poorer countries reduced their own commercial fishing and allowed foreign fleets into their waters.
Japan, Peru, and Russia crept to the top of the list for global fisheries landings.

From Africa to South America, China’s fishing fleet outstrips the competition
Survey – said to be the most comprehensive of its kind – says China’s fishing fleet operated more hours in 2016 than the next 10 biggest nations combined 

Today, China dominates.
The country ramped up its global fleet in the early 2000s, its vessels roaming foreign waters more than its own.
Technological advancements, such as sonar and radar, have enabled fishing vessels to track sea conditions and work through the night.

While industrial fleets are traveling farther and fishing deeper than a century ago, the number of fish caught has actually been falling since the 1990s.
Watson says the reasons differ across the world.
In some areas, fishing has been curtailed in the interest of sustainable management.
In others, the sea has simply been overfished.

 Far from home: Distance patterns of global fishing fleets

Global fisheries have evolved greatly over the past 150 years.
According to Watson, the next 150 could see important changes, too.
In particular, he sees a number of challenges.
Demand for seafood may rise even further as food systems on land falter under climate change, he says.
But if fuel becomes a more limited resource, fleets may not be able to travel as far offshore as they currently do.
This may result in an expansion of aquaculture, which could place even more pressure on coastlines.
“We’re beginning to see how everything is connected,” says Watson.
“It’s not just about looking at where catch comes from, but the bigger picture of fishing and our dependency on it.”

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