Author Archives: Rod Fujita

Coral Reef Thresholds for Ecosystem Management

(c) Jim Patterson Photography, https://jimpattersonphotography.com/

(c) Jim Patterson Photography, https://jimpattersonphotography.com/

By: Rod Fujita & Kendra Karr

Fisheries management is principally focused on managing fishing pressure, with the goal of keeping individual fish stocks healthy enough to produce good yields.  But fisheries also affect the basic processes that keep ocean ecosystems healthy.  This is why it is important to understand how many fish need to be in the system to maintain the many important services that an ocean ecosystem can produce — including the maintenance of biodiversity, tourism value, and fisheries — and to manage fisheries so that fish populations remain at about that level.

The evidence that fish are important regulators of ecosystem processes is particularly strong in coral reefs.  The abundance and variety of fish is one of the most striking aspects of a healthy coral reef.  Some species transport energy and nutrients between seagrass meadows and the reefs.  Grazing fish species on a healthy coral reef keep seaweeds that would otherwise over-grow the reef in check.   Predators regulate populations of prey species, responding to natural variability by adjusting their feeding rates and numbers.  On a healthy reef, many different species occupy each of these niches, and each does their job in a slightly different way.  This enables the reef to resist threats and other changes (like hurricanes) and to recover from very storms or human impacts, within limits of course.

Like many complex systems with many elements that affect each other in many ways, coral reefs don’t always change in a simple, linear way when one of the elements is altered.  Similarly, your car will run, albeit a little roughly, if a single spark plug isn’t working.  But if the starter doesn’t work, it won’t run at all.  Coral reefs can exist in many different states, ranging from one in which live coral dominates, supporting a highly diverse mix of species and generating high levels of multiple ecosystem services to a state in which most of the coral is dead, species diversity is low, and the reef is no longer producing valued ecosystem services.

Photo Credits: Left, Kendra Karr. Right, blog.soleilorganique.com

Photo Credits: Left, Kendra Karr. Right, blog.soleilorganique.com

Some changes in coral reefs are gradual, but some are not.  A tipping point occurs when small changes in human use or environmental conditions result in large, and sometimes abrupt, impacts to marine ecosystems.  Certain factors can push coral reefs over an ecological tipping point, so that they change dramatically from one state to another.

Because fish are such important regulators of the processes that maintain coral reefs in these different states, fishing can act as a driver, pushing the reef toward a tipping point.  Once a tipping point is crossed, changes to the reef occur rapidly.  In the figure below, the levels of various drivers of change are at levels which enable the reef to exist in a healthy state (position 1) – the width of the basin in which it rests and the height of the ridge that defines the basin depend on how many species are present, how many are playing redundant roles, how high productivity is, and many other factors that contribute to the resilience of the reef.

EDF 2012

EDF 2012

However, if the system’s resilience is reduced and/or a driver becomes strong enough, the reef can transition (position 2) to a new, less desirable state (position 3).

Our analysis of coral reef health metrics and fish abundance (collected over 20 years, from 1994 to 2011, across 19 countries throughout the Caribbean) shows that coral reef metrics shift in response to changes in fish density, a measure of abundance.  Moreover, just as theory predicts, some changes are abrupt and nonlinear.

Macroalgal cover increases as fish density decreases to about 90% of the maximum levels in the data set (which we take to be a proxy for unfished levels), and variance becomes very high.  This may be related to the tendency for complex, regulated systems to exhibit higher variability as regulation (in this case, by fish) is reduced.  For example, if the thermostat in your house is partially broken, the temperature in your house may fluctuate between 60 and 70 degrees, instead of being held within a narrow range of temperatures by a well-functioning thermostat.

A number of metrics — including the proportion of invertivore fishes, the number of fish species, and urchin density – change dramatically when fish densities fall to between 50 and 60% of unfished densities.

When fish densities reach 30% of unfished densities, the ratio of macroalgae to coral increases, the proportion of herbivorous fish in the fish community decreases, and coral cover drops markedly – the fact that the reef is in a different state becomes obvious.

EDF will continue to refine the use of coral reef ecosystem thresholds and advocate their use in setting aggregate catch limits in order to keep healthy reefs healthy and to restore reefs that are in transition or in less desirable states.

 

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Climate Change is Changing Fisheries

Recently, the impacts of climate change on fisheries have been in the news.  The emphasis has been on the inability of scientists to explain how climate change is affecting fisheries or to fix the problems it seems to be causing.  These include shifting distribution and abundance patterns of commercially valuable fish stocks – shifts that may leave fishermen stranded with very restrictive catch limits, even when they have been doing everything possible to protect and restore their stocks.  These problems are being felt acutely in New England, where catch of some valuable stocks has been highly restricted to rebuild stocks depleted by overfishing – but they face even more restrictions as scientists find less fish in the water, possibly due to migrations induced by climate change.

A better scientific understanding of how climate change influences the distribution and abundance of fish is certainly needed, but that may be less important than the need for more flexible human institutions that can rapidly adjust to those changes.

The fact that we’ve allowed greenhouse gases to accumulate in the atmosphere means that the ocean has warmed too.  The ocean is even more resistant to remediation efforts than the atmosphere due to its enormous thermal inertia.  The ocean will hang on to that heat for decades, resulting in changing temperatures at sea.  Because fish favor certain ranges of temperatures over others, this should cause fish stocks to migrate in pursuit of their favorite temperatures. A new study shows that catch composition has been changing over the last several decades in ways that support this hypothesis: warmer water species are being caught in areas where catch used to be dominated by cold water species.  This state of affairs demands institutions that are flexible and can adjust rapidly to changing conditions.

Most fishery institutions, on the other hand, seem inflexible and incapable of rapid adjustment to a changing world. For example, the Pacific Salmon Treaty of 1985 allocated harvest of shared stocks of salmon to the United States and Canada based on average distributions.  But then, changes in the distribution and abundance of salmon (which are prone to such changes, being migratory) resulted in a fish war between these two strong allies.  In many other fisheries, too, declines in fish stocks have led to declines in  allowable catch limits, leaving  fisherman who invested in boats and gear during boom times saddled with debt.

Catch share programs, in which shares of allowable catch are allocated to individuals or groups, are much more suitable to a world in which the climate is changing. Shareholders can buy or sell shares, allowing the fishery to contract or expand depending on how many fish are around.  For example, fishing capacity had built up to high levels in the Pacific groundfish fishery, resulting in a federal buyout of about half of the capacity.  However, the fishery was still constrained by very low catch limits for species depleted by decades of overfishing.  Catch shares have allowed the fleet to adjust to these new catch limits by incentivizing fishermen to extract more value from their catch and engage in creative strategies to avoid catching the overfished species. Read More »

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The Business of Marine Reserves: Achieving Financially Sustainable Ocean Conservation

photo credit: Phil's 1stPix via photopin cc

Ocean conservationists have been arguing for a long time that marine reserves are a good investment, because they help sustain many ecosystem services, including fisheries and tourism.  Various studies have helped to quantify the value generated by marine reserves, but a new study puts it all together and presents a convincing value proposition for marine reserves.  Now all we need are investors who can appreciate that value proposition and make it work economically, and the right combination of rules and governance that will make these new kinds of markets – ecomarkets – viable.

The benefits of marine reserves often outweigh the costs of establishing and maintaining them. You would think that there would be great demand for them, but instead the pace of marine reserve establishment has been slow and conflict-ridden.  Why? Because many groups of people benefit from the status quo, and would suffer short-term economic harm from marine reserves.  Also, the benefits of marine reserves take several years to accrue, while the costs are immediate.  And while some of the benefits are fairly concrete and flow to discrete user groups – like lower fishing costs and higher fishery yields near the borders – others are less concrete (e.g., biodiversity and aesthetics) and flow to many user groups (e.g. tourists and people who like natural environments), including some (e.g., future generations) that don’t have much say in present day decisions.

So theoretically, marine reserves can pay for themselves and then some.  But right now, few people want to invest in them.  How do we change that?

Investors need to know what the return is likely to be on their investment, and they need to capture that return directly.  They need to know that the risks of losing their money or not making the expected return are fairly well characterized and manageable. And the return must be commensurate with the risks. User groups which would suffer short term costs need assurance that they will benefit over the longer term and may need alternative ways to make money and feed their families while the benefits of marine reserves accrue.

This recent study represents one of the best available estimates of the potential return on investments in marine reserves (see our study for ideas on how to use actual markets to capture economic benefits of keeping ocean ecosystems healthy and intact).  But a business case must address these other factors if it is to attract investors.  And because marine reserves protect public trust resources in the ocean, where rights and responsibilities are unclear, certain enabling conditions must be in place for a marine reserve business case to be viable.

Read More »

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Fisheries Catch Data: A Tale of Two Approaches

photo credit: wanderlasss via photopin cc

To paraphrase F. Scott Fitzgerald, the test of a first rate intelligence is the ability to entertain two opposed ideas at the same time and still function.

Two views on the importance of catch data for estimating the abundance of fish populations are portrayed as opposing ideas in recent articles, but both of the “antagonists” display first rate intelligence by coming to the same conclusion: catch data send an important signal about the status of a fish population, but other kinds of information must be applied to avoid being confounded by all the other things that affect catch and come to a reasonably accurate estimate of fish abundance.

This argument over methodology may seem arcane, but the stakes are high: estimates of the status of global fisheries based on catch data, which are available for most fisheries, suggest they are in pretty poor shape, because catches have declined sharply in many of them.  But when one looks at stocks that have been assessed by scientists who take into account fishery-independent measures of abundance, the situation looks far less dire, because decreases in catch can result not only from decreased abundance, but also from changes in markets, environmental conditions, regulations, and even in what fish are called – Hilborn and Branch point out that in the 50’s, all sharks were put into only 7 categories, but now there are 36 groups for which catch data are collected, so that reduced catch in some of the earlier categories may merely be the result of re-classification.

So catch data provide a satellite-eye view of the whole world that is out of focus, while stock assessments provide really sharp images of your town.  Which is the more accurate depiction of reality?  Neither, of course.  These two perspectives must be intelligently synthesized to find reality. Read More »

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Social Entrepreneurs Saving the Ocean

 

Plastic trash on the beach

Photo credit: jschneid via photopin cc

*Re-Posted from Huffington Post Blog  

Social change requires the harnessing of social forces, and the more powerful the force, the more fundamental the change.  Moral outrage, a yearning for justice, and the desire for connection are all forces that have propelled social change movements throughout history.  They will continue to fuel social change now and in the future. 

But there is a very powerful force shaping the world we live in today that is not yet aligned fully with the environmental values that many of us hold, and that is the search for profit and well being through the investment of capital and labor — the profit motive.  Indeed, the profit motive has prevailed time and again over countervailing forces like ethical commitments to environmental stewardship, the desire for long-term economic well being, and even over the force of government regulation.

In a previous blogpost, I summarized a recent publication that lays out a strategy for aligning the profit motive with the conservation of coastal ecosystem services like carbon sequestration, storm surge protection, and recreational value — services that are usually unpriced by conventional markets, and so become subject to degradation.  The goal is to reverse alarming trends in mangrove deforestation, salt marsh dredging, and nearshore pollution by shaping markets that value these services, allowing people to do well by doing good. Read More »

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Managing for a Resilient Ocean

Good science should always guide policy.  In the ocean, policy reflects decades of scientific work on single species and on single endpoints, like water quality.  However, it is now clear that ocean ecosystems are more than the sum of their parts, and policy needs to catch up to this new scientific understanding.

Of course, we must continue to protect the aspects of ocean ecosystems that we value the most.  Fisheries need catch limits to keep stocks at sustainable levels.  Pollutants need caps to keep waters fishable and swimmable.  Forestry and farming need best practices and standards to keep estuaries healthy.  But it turns out that ocean ecosystems have tipping points – ecological thresholds beyond which they undergo dramatic changes.

Healthy and resilient ocean ecosystems function similar to the United States government’s system of checks and balances—different species do similar things but in slightly different ways, which help keep these systems both interconnected and even-keeled. However, when we reduce species populations so much they can no longer do their part, we alter the natural balance of the system, which can have grave effects.

Luxuriant kelp forests that support marine mammals and a myriad of other species provide us with various ecosystem services like seafood, agar (sugar made from kelp), recreation, and sheltering the coastline from waves. However, these habitats can turn to rocky barrens very rapidly when they reach their tipping points. We witnessed this in the 1800s when fur hunting became prevalent—decreasing the sea otter population. With fewer sea otter to consume urchins, urchins became overabundant, overgrazing the kelp and causing forests to disappear.

Fortunately, science is providing insights into the factors that make ocean ecosystems more capable of resisting these kinds of changes, and more able to bounce back when they are damaged; in other words, the attributes that make some systems more resilient than others.  Having lots of species with different ecological jobs (biodiversity and niches) is very important, as is having several species doing the same job but in slightly different ways (functional redundancy).  Lots of genetic diversity within species and populations is important as well.  It's a little like rocket science: rockets are complex systems that are made more robust and resilient (i.e., less likely to blow up) by building in redundant subsystems.  Nature has done that one better by building in even more diversity, allowing coral reefs for example to recover from hurricanes and even volcanic eruptions that devastate human communities.

In an ocean in which the temperature, pH, currents, weather, and human uses are changing, it makes much more sense to manage for resilient ecosystems than manage for maximum sustainable yield of one species or another.  Who knows what the next big impact to the ocean will be?  We need to increase resiliency so that no matter what, ocean ecosystems can persist and continue to provide the many valuable ecosystem services upon which we depend.  Our new paper draws on the science of ecosystem resilience and lays out a policy framework for achieving this goal.

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Ecomarkets: Scaling Up Marine Conservation

Originally published in the Huffington Post Green Blog: 12/30/12

The ocean is enormous, supporting a vast array of life while providing food, fuel, recreation, and spiritual rejuvenation.  But efforts to conserve the ocean, though valiant, are meager compared to the scale of the threats to the ocean.  Ocean conservation advocates have achieved many notable successes, such as dramatic reductions in certain kinds of pollution, the establishment of Marine Protected Areas (MPAs), and major improvements in fishery management in some areas of the world.  However, a recent analysis that EDF participated in suggests that 40% of the ocean is still strongly impacted by a range of threats, including shipping, the modification of rivers and estuaries, coastal development, pollution, and overfishing.  How can we scale conservation efforts up to match the ocean's vastness and the severity of these threats?

To answer this question, we must first accurately diagnose the problem. Conventional markets, which drive so much of mass human behavior, only value a few of the many goods and services that the ocean provides, like fish and oil.  The critically important ocean processes that produce fish, regulate the climate, assimilate wastes, and provide all of the other goods and services on which the diversity of ocean life and we humans depend are generally not valued by markets.  Because markets see value only in parts of the ocean, and not in the whole, the valuable pieces are extracted and the rest is degraded.

Conservation has been pushing back against market forces, among the most powerful forces in the world, in the form of regulation.  While regulations like water quality standards and MPAs can be very effective, they often depend on high levels of enforcement because they are working against market forces and the incentives to exploit valuable resources without stewarding the ecosystems that support them.  Regulations in this context are often perceived as threats to livelihood and human welfare, resulting in opposition and conflict.  It is not surprising that it typically takes many years and sometimes decades to get ocean conservation measures in place. Read More »

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Finding the Ecological Cliff and Staying Away from It: Thresholds for Sustainability

In “The Tipping Point: How Little Things Can Make a Big Difference,” author and journalist, Malcolm Gladwell explains how sociological changes often happen very quickly and unexpectedly.   He describes a tipping point as “the moment of critical mass, the threshold, the boiling point.”

It turns out that many natural ecosystems have tipping points too, called ecological thresholds.  Healthy ocean ecosystems can resist change, exist in alternative states and recover from storms, earthquakes, volcanic eruptions – and even from human activities like pollution and fishing.  Having more than one species that do similar things but in slightly different ways helps ecosystems stay healthy; i.e., makes them resilient.  But when we reduce species so much that they can't play their ecological roles or when we stress the system too much, these ecosystems can reach a tipping point and change rapidly from beautiful, productive systems to damaged systems that are incapable of creating the wonders and benefits they once produced. Read More »

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