EDFish

Selected tag(s): Ecosystems

New research quantifies growing threat plastics pose to coral reefs

Alamy Richard Whitcombe

Plastic waste in the ocean poses a wholly unexpected and serious threat to coral reefs.  The results from new research published in Science are sobering, but there is hope if we act now to mitigate the most significant threats facing corals and the vulnerable communities who depend on healthy coastal ecosystems for food and livelihoods.

As one of the co-authors, I was greatly surprised at the elevated risk of disease to corals caused by plastic: from 4% in corals without plastic, to 89% in corals with plastic.  Given that the study estimated that there are already more than 11 billion plastic items on reefs across the Asia-Pacific region, and that plastic loads in the ocean are expected to grow radically, this is bad news indeed. Read More »

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Mexico is making strides to improve fisheries management and conservation

Photo credit: Carlos Aguilar

Photo credit: Carlos Aguilar

2015 looks to be the year Mexico takes significant action to improve the sustainability of its fisheries.

Mexico is the world’s 16th largest fishing nation and one of the globe’s richest in marine biodiversity. The productive waters of both of Mexico's coastlines teem with a wide array of species that sustain commercially important fisheries.  These include hundreds of commercially valuable species of finfish, clams, squid, sardines, and tuna that share the waters of the Pacific, Gulf of Mexico and Caribbean with wildlife such as whales, dolphins, seabirds, and turtles.

This year, Mexico's Federal Fisheries Commission (CONAPESCA) and Federal Fisheries Institute (INAPESCA), are working together with fishing communities and state authorities to implement stronger measures to protect marine biodiversity and ensure sustainable fishing livelihoods.  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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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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Ocean Conservation Should not be a Partisan Issue

Stetson Bank Coral and Sponges

Stetson Bank Coral and Sponges. Photo credit: Frank and Joyce Burek

No matter what happens at the polls today, the ocean and the fish that live in it will still require our attention and conservation efforts. With all the politics and rhetoric circulating throughout the media, the fact that oceans and other vital ecosystems provide invaluable resources and benefits to the billions of people on this planet tends to go unnoticed. Even worse, there is a tendency to paint the environment as a partisan issue, when regardless of your political beliefs—ensuring we have a healthy natural world is essential to your survival and happiness for the future.

The oceans cover 71% of the Earth’s surface and contain 97% of the world’s water. An estimated 20,000 species of marine fish swim beneath the largely unexplored waters, along with complex plant and animal life including coral reefs, sea grasses, whales and sharks. Billions of people globally depend on fish as their primary source of protein, and the economic value of fishing for their livelihood. Many of these people live in poor, undeveloped countries and will rely more heavily on the ocean as populations increase and global warming impacts their ability to cultivate food on land. The reality of our global dependence on the ecosystem services that the ocean provides becomes more evident with studies such one which recently came out in Science, citing that 80% of the world’s un-assessed fisheries are in worse shape than previously thought. But there is hope if we act now to align the right incentives and increase the economic value of fisheries, while putting fishermen at the forefront of conservation.  Ensuring that the world’s fish stocks are replenished is a human imperative, not a political talking point. Read More »

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“Red Herrings” in the Gulf of Mexico – Part 4: Persistent Effects?

This is the last post in a four part series discussing the ongoing – and "cascading" – effects in the Gulf, not from "oil," but rather its toxic components and their impacts on sensitive ecosystems. Read the rest of the series.

Once the more easily processed materials and their breakdown products have completed their complicated journeys through the Gulf ecosystems, that still leaves the toxins that don’t break down easily, both the polycyclic aromatic hydrocarbons (PAHs) and metals like arsenic that are associated with drilling accidents. By some estimates, as much as a quarter of the total volume of these toxins might end up back on the sea floor, and subjected to processing – and reprocessing – by sediment-eating "infaunal" invertebrates (worms and such), which are prey for bottom-feeding fishes and crustaceans. The same applies to marshes and beaches — foraging grounds for many sought-after fishes — as well as protected species, like migrating shorebirds.


These relationships provide re-entry points for toxins back into food webs that sustain seafood production.

It could be many years before those chemicals wend their way – much more slowly, and through different pathways – through both the ecological systems of the Gulf and their human counterparts.

The pathways for many of these longer-lived toxins will also be altered as human uses resume. Shrimp trawling, for instance, will stir up sediments, potentially exacerbating the impacts of both toxicants and oxygen-demanding substances.

Again and in conclusion, some elements of the complex ecology of the Gulf of Mexico may well get off scot-free from the disaster. But many others will be heavily impaired, at least for some time. Taken together, there will be a significant total effect on the ecological systems and on the productivity and safety of seafood from the Gulf, significant human population impacts are expected, and those impacts must be remediated.

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