Selected tags: Climate change

Closed areas can decrease uncertainty in effects of climate change on New England Fisheries

Gulf of Maine Map

Photo Credit: New England Coastal Wildlife Alliance

As fishermen around New England will be the first to point out, this summer, much like last year, has been abnormal. The ocean waters were warmer and cod, haddock, and flounders—the mainstay of our fishing industry for centuries—are increasingly elusive. There’s plenty of blame to go around, including decades of mismanagement and overfishing, inexact science and a mismatch in abundance of certain predatory species. Looking beyond these factors, the impact of climate change on fisheries is another factor driving fish abundance that’s worth a hard look.

The level of carbon dioxide in the Earth’s atmosphere has now exceeded 400 parts per million, contributing to rising ocean temperatures. Some of the fastest increases in the last few decades have occurred in the Northwest Atlantic, and 2012 registered the largest annual increase in mean sea surface temperature for the Northwest Atlantic in the last 30 years.  

It is clear that climate change is disrupting New England’s fisheries right now; it is no longer an abstract, future scenario.

In the face of this evidence, fisheries managers need to factor in climate change alongside fishing effort and other elements when determining how to manage and rebuild fish stocks. The impacts of climate change can prevent fisheries management inactions from rebuilding fish populations, and conversely, excess fishing pressure can hinder the ability of a fish population to adapt to changes in climate. As I have written recently, a network of well-designed closed areas represents a promising management strategy to address the effect of climate change on fisheries. Read More »

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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. Read More »

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Newsflash! Warming oceans=changes in fish populations and ecosystems

A number of scientific studies indicate that warming waters are affecting fish populations globally—and often in unpredictable ways. This finding is significant for fisheries management because as fish populations shift, whole ecosystems are changed. A recent study covering 40 years of data illuminates these changes in fish distributions and a Huffington Post article examines the research conducted to date and highlights the uncertain implications of this knowledge. The article extensively quotes our own scientist and Director of Spatial Initiatives, Jake Kritzer. Jake comments on the difficulty of making management predications without a complete understanding of how complex underwater ecosystems are shifting:

“It's an immensely complicated situation. You have climate change overlaying everything, and it seems to be changing the way everything works, which means we have a lot of problems. It's getting harder and harder to assess the stocks, to model them and understand their dynamics and predict what's going to happen. Because those models are based on years and years of experience reading fish stocks and studying them, they have been tested over a long time and they rely on a certain set of assumptions and conditions that now seem to be rapidly changing. Tools that have been fairly well established and worked well in the past just don't seem to be working as well anymore."

Read the full Huffington Post article: http://www.huffingtonpost.com/2013/05/17/ocean-climate-change-fishing-industry_n_3275505.html

Access the recent study published in Nature from researchers in British Columbia: http://www.nature.com/nature/journal/v497/n7449/full/497320a.html

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Building Resilient New England Fisheries in the Face of Climate Change

Photo Credit: Natacha Hardy.
Alex Koeberle and Scituate Fisherman Frank Mirarchi

By: Alex Koeberle and Jake Kritzer

Following the hottest summer ever on record, the Atlantic coast was rocked recently by super storm Sandy, both stark reminders that climate change is increasing the frequency and severity of extreme weather events.  This year had already seen effects of climate change take on a more prominent place in marine conservation debates.  In July, renowned Australian ecologist Dr. Roger Bradbury argued that the fate of coral reefs is essentially sealed due to warming waters, rising seas, acidification and extreme weather (although other prominent voices were quick to counter such doomsday predictions).  Closer to home, an effort to restore Atlantic salmon to the Connecticut River was ended after nearly a half-century, in part because changing ocean currents, temperature regimes and plankton production might be impairing the ability of salmon to survive at sea and migrate back to spawn.

It is not only salmon that are contending with effects of climate change in New England.  The region is seeing sea levels rising faster than many other places around the globe, which threatens to drown salt marshes already struggling with excessive nutrient loads.  Marshes help buffer coastal areas against storm surge, and provide vital nursery and feeding grounds for many important fish species.  Ocean waters are not only rising but warming as well, one consequence of which has been a dramatic shift in the distribution of cod north of the primary fishing grounds in the western Gulf of Maine.  Also, rainfall patterns are becoming increasingly erratic, altering salinity profiles and plankton production, which hampers productivity of species throughout the food web. Read More »

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Disaster Funds and Cod Problems: Setting the Record Straight about Fisheries in New England

Cod

Photo from NOAA

New England has received a lot of media attention recently about the fisheries disaster declared by President Barack Obama. The precipitous decline in groundfish in New England waters has created an imminent need to help fishermen and fishing communities that depend on stable healthy fish populations.

It is important to dispense with false rumors and to set the record straight.  There is an effort on the part of some to claim that catch shares are somehow responsible for the New England groundfish population declines. To claim this is to suggest that fishermen have exceeded their catch limits and are not following the rules. This is simply not true. In fact, sector fishermen have been working hard to stay under their catch limits, and in some cases remain well below these limits.

In reality, the disaster declaration was based on the fact that there are changes happening in the ecosystem that are impeding the rebuilding of fish populations.  We are forced to confront the frightening reality that fishing is changing in part because our oceans are changing.  We are dealing with a resource problem, not a management problem. Read More »

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Climate Change Threatens Chemical Composition of the Oceans

Rod FujitaThe recent U.N. Climate Change conference in Copenhagen highlighted the range of challenges associated with fighting climate change, from cutting energy use to financing clean technology in developing countries.  Why the global sense of urgency and focus?  Because the impacts of climate change are already being felt.  Most of our discussions center on the dangers of sea level rise, which is already inundating low-lying islands and valuable wetlands; on changes in precipitation and air temperature, which will affect everything from agriculture to asthma; and on the shift in seasons and habitat that will make life difficult for trees, butterflies, and the other wildlife we are familiar with.

Enormous threats indeed.  And it is perhaps inevitable that we are focused on the land and our fellow terrestrial inhabitants.  But let us not forget the fact that we are changing the ocean profoundly in many ways.  A recent study suggests that over a third of the entire ocean is heavily impacted by human activities, and that there is no longer a single patch of seawater anywhere that can be said to be pristine.  And incredibly, we are not just affecting patches of the ocean here or there – we are changing the very chemistry of the seas, chemistry that has remained stable for millennia and which defines the parameters for life in the sea and also for the habitability of the planet for us.

All living systems are buffered from extreme change by their chemistry.  If not for the carbonate/bicarbonate and other buffering chemicals in our blood, the pH (a measure of acidity) would fluctuate wildly and none of the myriad proteins or enzymes essential for life would function.  Because pH is a logarithmic scale, very small changes in pH can be disastrous for life – for example, a change of less than one pH unit is lethal to humans. Oceans along coast

The ocean is a gigantic living system, and is perhaps one of the best-buffered systems on the planet.  Enormous quantities of buffering chemicals have been entering the ocean each year for billions of years.  Remarkably, though, even the ocean is not impervious to the impacts of fossil fuel combustion and carbon dioxide emissions. 

As atmospheric carbon dioxide concentrations have risen, the ocean has steadfastly taken up about 2 billion tons of it every year, protecting us from an even more serious climate crisis than we have already.  However, carbon dioxide reacts with seawater to create carbonic acid.  As a result, while the pH of the ocean varies widely in response to local conditions, scientists have detected a noticeable drop in pH (an increase in average acidity) over the last 20 years and project a decrease in pH by 0.3-0.4 units – a huge change -  by 2100 if nothing is done to reduce carbon dioxide emissions. 

Read More »

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