Fish larvae float across national borders, binding the world’s oceans in a single network


Larval black sea bass, an important commercial species along the US Atlantic coast.
NOAA Fisheries/Ehren Habeck

Nandini Ramesh, University of California, Berkeley; James Rising, London School of Economics and Political Science, and Kimberly Oremus, University of Delaware

Fish populations are declining around the world, and many countries are trying to conserve them by regulating their fishing industries. However, controlling fishing locally may not do enough to strengthen fish populations. Often one nation’s fish stocks depend on the spawning grounds of a neighboring country, where fish release eggs and sperm into the water and larvae hatch from fertilized eggs.

We do research on oceans, climate and fisheries. In a recent study, we showed that global fisheries are even more tightly connected than previously understood. The world’s coastal marine fisheries form a single network, thanks to the drift of larvae along ocean currents.

This suggests that country-by-country fishery management may be fundamentally insufficient. If a fish species that provides food to one country should decline, the amount of fish spawn, or eggs and larvae, riding the ocean currents from there to other countries would also decline dramatically, resulting in further loss of fish elsewhere.

Many countries live with this risk, although they may not realize it. To manage fisheries effectively, nations must understand where the fish in their territories originate.

Ocean currents affect the speed at which fish eggs and larvae drift and vary through the year. This map shows surface current speeds for January: yellow = fastest, dark blue = slowest. Each country’s territory is highlighted with red dots during the month of maximum spawning activity in that country. In each territory, a different number of species spawn in each month of the year. The red dots appear in the month during which the largest number of species spawn in that territory.

Crossing national borders

Fish don’t recognize political boundaries, and regularly travel internationally. Scientists have tracked adult fish movements using electronic tags, and have shown that a few species migrate over long distances.

Countries and territories have negotiated agreements to ensure sustainable sharing of migratory fish. One such agreement joins several nations in the Western and Central Pacific Fisheries Commission to ensure that the territories fish cross share them sustainably.

But fish eggs and larvae are much harder to follow. Many species lay eggs in large numbers that float near the ocean surface. When they hatch, larvae measure a few millimeters long and continue to drift as plankton until they grow large enough to swim. During these stages of the life cycle, ocean currents sweep fish spawn across international boundaries.

Simulating the journeys of eggs and larvae

Like weather on land, the pattern of ocean currents varies with the seasons and can be predicted. These currents are typically sluggish, traveling about an inch per second, or less than 0.1 miles per hour.

There are a few exceptions: Currents along the eastern coasts of continents, like the Gulf Stream in North America or the Kuroshio in Asia, and along the equator can be significantly faster, reaching speeds of 2 miles per hour. Even a gentle current of 0.1 miles per hour can carry spawn 40 miles over a month, and some species can float for several months.

Government and academic scientists use a vast network of satellites, moored instruments and floating buoys to monitor these surface flows. Using this information, we performed a computer simulation of where drifting particles would be carried over time. Scientists have used this type of simulation to study the spread of marine plastic pollution and predict where debris from plane crashes at sea could have washed ashore.

Different fish species spawn in different seasons, and a single species may spawn in several months at different locations. We matched the seasons and locations of spawning for over 700 species with ocean current data, and simulated where their spawn would drift. Then, using records of where those species have been fished, and information about how suitable conditions are for each species in different regions, we deduced what fraction of the fish caught in each country arrived from other countries because of ocean currents.

A small-world network

Scientists and policymakers can learn a lot by studying these international connections. Each species that floats across international boundaries during its plankton stage represents a linkage between countries. These linkages span the world in a dense, interconnected network.

Each color represents a region in the network of fish larvae connections. This map shows the strongest 467 connections among a total of 2,059 that the authors modeled.
Nandini Ramesh, James Rising and Kimberly Oremus, CC BY-ND

At a global level, this network of connections has an important property: It is a small-world network. Small-world networks connect regions that are far apart to each other by just a few steps along the network. The concept is rooted in social scientist Stanley Milgram’s 1960s experiments with social networks, which found that it was possible for a letter to reach almost any total stranger by passing through six or fewer hands. Milgram’s work was popularized in the 1990 play “Six Degrees of Separation.”

Among fisheries, the world seems even smaller: We found that the average number of degrees of separation among fisheries is five. This means that local problems can become global risks.

For example, imagine that a fishery collapses in the middle of the Mediterranean. If the population in one spawning region collapses, it could quickly put pressure on neighboring fisheries dependent upon it. If fishers in those neighboring countries overfish the remaining population or shift to other species, the disturbance can grow. Within just a few years, a fisheries disturbance could travel around the world.

We assessed how countries would be affected in terms of food security, employment and gross domestic product if they were to lose access to fish spawn from other territories. The most affected countries cluster in the Caribbean, the western Pacific, Northern Europe and West Africa. These hotspots correspond to the network’s most clustered areas, because the effects of these flows of fish spawn are most pronounced where many coastal countries lie in close proximity.

International flows of fish eggs and larvae affect countries’ total catch, food security, jobs and economies.
Nandini Ramesh, James Rising and Kimberly Oremus, CC BY-ND

Thinking globally about fisheries

Because the world’s fisheries are so interconnected, only international cooperation that takes flows of fish spawn into account can effectively manage them. Aside from egg and larvae connections, fisheries are linked by movements of adult fish and through agreements among countries allowing them to fish in each other’s waters.

All of this suggests that fishery management is best conducted at a large, international scale. Proposals for doing this include defining Large Marine Ecosystems to be jointly managed and creating networks of Marine Protected Areas that safeguard a variety of critical habitats. Ideas like these, and careful study of interdependence between national fisheries, are crucial to sustainable use of the oceans’ living resources.

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Nandini Ramesh, Postdoctoral Researcher in Earth and Planetary Science, University of California, Berkeley; James Rising, Assistant Professorial Research Fellow, London School of Economics and Political Science, and Kimberly Oremus, Assistant Professor of Marine Policy, University of Delaware

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Chief Scientist’s report lays a solid foundation for reforming Australia’s electricity network


Anne Kallies, RMIT University

Chief Scientist Alan Finkel’s preliminary report on the National Electricity Market (NEM), released on Friday, sets the scene for a comprehensive review of the electricity network.

The report identifies that energy and emissions reduction policy must be brought together. There is no doubt that the electricity sector will be central to any emissions-reduction efforts in Australia.

However, the report also appears to see the rise of renewable energy in the electricity system as a disturbance rather than an opportunity.

The report discusses how the NEM should be reformed in response to a changing mix of generators – coal, gas and renewables. But it does not proactively seek to discuss the role of the NEM in achieving the emissions reductions and renewable energy targets of federal and state governments.

Transition doesn’t have to break the grid

The new National Transmission Network Development Plan 2016 by the Australian Energy Market Operator (AEMO) shows what such a proactive approach might look like. It shows that transmission investment within and across state borders will be crucial for Australia’s energy transformation.

International examples can provide insights into what these strategic investment solutions could be. The Finkel report mentions, for instance, the proactive designation and connection of wind zones in Texas. Other examples are the facilitation of offshore network development in the UK, and the German north-south interconnectors.

A similar mechanism could allow the NEM to access renewable energy resources in new areas, as well as upgrade existing networks to increase renewable uptake. As the AEMO plan shows, these types of measures can “smooth the impact of variable renewable energy” and “improve system resilience”.

Efficiency, reliability and reduced emissions

The Finkel report queries whether the National Electricity Objective (NEO) needs to be amended to achieve the integration of energy and emissions-reduction policy. The current objective is:

…to promote efficient investment in, and efficient operation and use of, electricity services for the long-term interests of consumers of electricity with respect to – price, quality, safety, reliability and security of supply of electricity; and the reliability, safety and security of the national electricity system.

The objective sets the parameters for developing electricity market rules and limits the scope of regulatory decision-making.

It reflects the purpose of the NEM at the time it was introduced. The NEM was initially introduced as a market-based governance framework to achieve the public service of electricity as efficiently and reliably as possible.

The report states that we need to find solutions to address the so-called “energy trilemma”. Energy policy needs to strike a balance between “security, affordability and environmental objectives”.

While the first two of these objectives are covered in the electricity objective, the last – environmental objective – is not. The NEO should reflect these changed consumer expectations.

In the age of climate change, we expect our electricity system to be reliable, affordable and green. A rephrasing of the NEO would allow for more innovative approaches to proactively develop market rules to facilitate renewable energy.

Expanding the objective would also see Australia in good company. Both the UK and German regulatory objectives contain express links to emissions reductions (UK) or environmental compatibility and renewable energy (Germany).

Putting the puzzle pieces together

The report argues for a “whole-of-system approach” to developing the energy system. The report discusses especially to what degree states and other institutions in energy markets need to work together to achieve this.

However, we also need national oversight to develop the grid. More advanced energy transition experiences in Europe show such a refocus of market reform.

Coordinated planning across the NEM will be crucial to achieve this whole-of-system perspective. While the market operator, AEMO, has a limited planning role in the NEM – identifying opportunities for network investment – there is currently no mechanism to encourage planning for the reliability and security of the whole of the NEM. Network businesses invest to ensure the reliability within their networks – contained within state borders.

Germany provides an example of how a whole-of-system approach could be achieved. German law compels the different network businesses to cooperatively develop a national grid development plan based on scenario frameworks and overseen and approved by the Federal Network Agency. Similar cooperative mechanisms could be introduced in the NEM regulatory framework.

What about climate adaptation?

The report mentions two examples of the challenges climate change might pose to the network, the black-out in South Australia and the drought in Tasmania. In both cases, a natural event combined with an interconnector (transmitters between states) fault triggered a challenge to energy security. Not mentioned in the report are the 2009 bushfires in Victoria, when a significant number of devastating fires were caused by failed electrical assets.

All of these kinds of extreme weather events can be linked to climate change. The need to adapt to more frequent and more severe weather events should be an essential part of a review into the security and reliability of the electricity sector.

While this is a preliminary report only, it picks up on many pertinent issues. This short analysis covers only some of the issues raised in the report. The prelimiary report is now open to public submissions. This provides an outstanding opportunity to consider and shape the future of the electricity network.

The Conversation

Anne Kallies, Lecturer, RMIT University

This article was originally published on The Conversation. Read the original article.

Netherlands: Building the World’s Largest Electric Vehicle Charging Network


The link below is to an article reporting on the Netherlands’ plans to build the world’s largest network of electric vehicle charging stations.

For more visit:
http://inhabitat.com/abb-to-build-worlds-largest-network-of-electric-vehicle-fast-charging-stations-in-the-netherlands/

Australia: NSW – Warrumbungle National Park


In the aftermath of a bushfire that has swept through four fifths of the Warrumbungle National Park, authorities must now determine just what is to be done in one of Australia’s premier national parks. That moment may not have yet arrived, given that the the bushfire continues to burn in the region and the threat has not yet been eliminated. When that time comes the true extent of devastation in the national park will seem overwhelming.

The extensive network of bushwalking trails, bridges and lookouts have been severely damaged and the visitor’s centre has been destroyed. Fears remain for wildlife in the park, particularly the Koala and Rock Wallaby populations.

For more visit:
http://www.theage.com.au/environment/conservation/reserve-burnt-to-a-cinder-20130119-2d000.html
http://www.australiangeographic.com.au/journal/bushfire-changes-warrumbungle-national-park-.htm
http://www.australiangeographic.com.au/journal/bushfire-damage-at-australias-largest-observatory.htm
http://www.abc.net.au/news/2013-01-14/homes-destroyed-in-nsw-bushfire/4463136
http://news.ninemsn.com.au/national/2013/01/18/05/00/firefighters-brace-for-nsw-outbreaks

Article: Australia Creates World’s Largest Marine Reserve Network


The link below is to another article covering Australia’s plan to protect large areas of our coastline with a Marine Park network.

For more visit:
http://blogs.smithsonianmag.com/science/2012/06/australia-creates-worlds-largest-marine-reserve-network/

Article: Australia’s Marine Park Network


The link below is to an article reporting on Australia’s amazing new network of marine parks.

For more visit:
http://www.acfonline.org.au/news-media/news-features/world-first-national-ocean-protection