Adaptation - Economic Mechanisms

Last time we looked at how ecosystems can be configured or even engineered so as to limit the vulnerability posed by climate change effects to fisheries and coastal communities. This is a typical adaptation response - the approach looks at how to bolster resilience in the face of climate change. Today we will examine another adaptation strategy.

One branch of mitigating fisheries decline is through implementing economic mechanisms to make sustainable business a more financially viable course of action for those who exploit fish stocks. An IFAD report (2014) suggests that promoting certification schemes can act to limit exploitation of stocks. The idea behind this is that sustainably managed fisheries are rewarded for their adaptation efforts by receiving certification which they can stamp on their products. If certification is sufficiently promoted, it can become a gold-standard for goods and products in a particular sector. In order to entice buyers, producers are then incentivised to take relevant sustainability and adaptation measures. No doubt, you're familiar with the Forest Stewardship Council (FSC) logo present on all certified goods, and marine fisheries have their own certification in the form of the Marine Stewardship Council (MSC) certification. Formed by a partnership between the WWF and Unilever in 1996, the MSC gained became an independent organisation when it ceased to receive funding from the aforementioned and sought investment from other sources from June 1998 onwards. As Gulbrandsen (2009) points out, the certification scheme has been a success in that it has encouraged co-management of fisheries by scientists, governments and fishers. However, many fishers who share their resource with others are unable to gain certification due to the actions of others, beyond their control. As such, a fisher could comply fully with MSC regulations and not receive certification due to unsustainable practice by others. Precisely because of this, by 2009 certification had been awarded to only three developing countries, where fishing takes the form outlined above.

Additionally, insurance services are an option to encourage adaptation measures. Quite simply, insurance products designed for fishers and fish farmers greatly improve their resilience by providing a safety net and financial stability in times of disaster, such as extreme weather events likely to result from climate change. Furthermore, clauses can be included in the insurance contract which ensures the adoption of best management practices, or BMPs (IFAD 2014). Index-based insurance policies have been offered to coastal communities in Peru, providing fishers some level of stability in the face of unpredictable climate features such as El Niño (FAO 2014).

Adaptation - Ecosystem Approaches

So far we've looked at how the world's fisheries are likely to be affected by climate change. Today we will look at adaptation measures that can be taken. Adaptation measures involve accepting as inevitable the changes that will result from global warming and subsequently adjusting practices in order to limit the threats that these changes will pose to social and environmental systems.

A report by the Food and Agriculture Organisation of the United Nations (FAO 2014) identifies two forms of adaptation approaches. Autonomous approaches involve the 'spontaneous reaction to environmental change'. This would include the local-scale shift by fishermen from one time or location to another in with movement of species. By contrast, planned adaptation approaches involve taking 'planned action based on climate induced changes'. An example of this would be funding research to identify species that are resistant to salinity and temperature fluxes and adopting them in aquaculture schemes.

Clearly, what we see here is a distinction between 'local' environmental knowledge in the form of autonomous approaches and international-scale science as implemented by planned adaptation. As we will see later, perhaps a synthesis of the two is an option to consider in the future.

As we've seen in previous posts, one problem associated with global warming is the potential for extreme weather events (BBC 2014) which can have disruptive implications for coastal fisheries and aquaculture activities. A report by the International Fund for Agricultural Development (IFAD 2014) proposes disaster risk management as a way of limiting the vulnerability of local communities and ecosystems to the effects of climate change. Traditionally this has been done through 'hard' engineering techniques, such as the construction of concrete revetments to protect coastal zones. Increasingly in recent years, however, there has been a shift to an 'ecosystems approach' to risk reduction. At the core of this is improving resilience by strengthening ecosystem stability and functioning, whilst simultaneously encouraging sustainable human activity that can maintain this ecosystem stability. This is very much a developing area of adaptation, and for more information you can enroll on this free online course run by UNEP on disasters and ecosystems which will run from January.

The FAO report (2014: 25-26) points to the Gulf of Mexico as an example of ecosystem risk management. Mexican authorities have utilised coastal restoration and wetland conservation in their ambition to bolster ecosystem functioning and thereby augment local resilience.

 

Figure 1 - Mexico's rich coastal mangrove ecosystems

Next time we'll be looking at the use of financial mechanisms and instruments in mitigation strategies.

South African Marine Reserves

In the latest installment in their series of articles on global food supply, National Geographic have included an assessment of South African marine reserve efforts, designed to limit human exploitation of fish stocks. I recommend you take a look at this informative piece, as in the coming posts I will be looking at adaptation and mitigation measures that can be taken to help alleviate the pressures imposed by climate change on fisheries.

Tracking the world's fisheries

There's been quite an important development in the analysis of fisheries in the last few days. A collaboration between Oceana, Google and SkyTruth has led to the release of a prototype platform called Global Fishing Watch (more on this here). The software uses satellite data to track global commercial fisheries activity, and once the public version is released it will allow ordinary citizens the opportunity to track and view global fisheries dynamics as well as the ability to update and contribute with their own information.

We've seen in previous posts that at present, fisheries are considerably lacking in assessment and analysis. This lack of information has led to much of the uncertainty. Pereira et al. 2010 highlight that not only is this absence of information detrimental for understanding of present phenomena, it severely limits the quality of modelling that scientists construct in an effort to predict future changes.

While it is too early to say for certain, this new development might be able to remedy some of these problems. Satellite data will be able to provide large-scale views of fish migrations and stocks, and local data contributed by citizens may be able to provide more detailed, specific information. It's also a great idea to involve 'normal people' in this project, as the workload is too vast for a single governing body to do on its own. Furthermore, by getting involved local people could take an interest in issues and perhaps shift to more sustainable practices. They might also have superior knowledge and understanding of the local geography and fisheries dynamics.

I think this project is definitely something to keep an eye on and hopefully it will provide much needed data once the public version has been released.

Aquaculture

When you think about it, the global fish industry is peculiar in one aspect. Whereas the majority of food production has progressed to human controlled cultivation, or farms, over the last several thousand years, it would seem that fish catch is the last remaining example of mass-scale hunter gathering. After all, the mobile nature of fish means that the logical action is to gear up your boat, set sail and hope for a good catch. Increasingly however this seems to be changing.

Recent decades have seen expansion in aquaculture, an attempt to replicate terrestrial agricultural practice in the form of 'fish farms'. Typically, this is achieved through setting up nets in the sea not too far from the coast, populating them with a particular fish species and then providing required conditions and nutrients to raise them in much the way pastoral farmers have farmed livestock for millennia.

The figure below shows that at present, over half of seafood is still wild caught while 45% is sourced from farms. It is predicted that by 2030, aquaculture will dominate production with a 62% share. Many have hailed aquaculture as the solution to many existing problems with global fish harvesting, including overexploitation by humans.

Figure 1 - Global seafood consumption (Source: World Bank).

The extent to which aquaculture can be seen as the long desired fix to fisheries problems is highly contestable. One thing that is quite certain however is that aquacultural practices are likely to be affected by climate change.

A recent IPCC report (2014) pointed out that despite their seeming independence from the larger ocean ecosystem, fish farms will still experience difficulties. The food stocks for many farmed fish species are anchoveta. Declines in this pelagic fish stock will have the result of a reduced food source for aquaculture, leading to declines in output and possible price spikes.

However, unlike many advanced aquaculture technologies found in the global north, many poorer regions of the planet are reliant on ecosystem services to raise their stock. So any changes to the ecosystem at large, which have been mentioned in previous posts, will have an impact on their farms (IFAD).

Additionally, extreme weather events resulting from climate change are likely to inflict damage on coastal aquaculture projects, making it an increasingly infeasible business endeavour fraught with uncertainty and instability.

There have been attempts in recent years to carry out fish farming on land with the aid of vast tanks. However, in many cases this has proved to be too costly and the resulting waste can lead to severe eutrophication in nearby freshwater systems if disposed off improperly.

If you've been following the blog regularly, it might seem like quite a bleak forecast so far. Predictions of so many large scale disruptions in the future can seem a bit overwhelming, but from next week we'll be looking at what measures and actions can be taken to reverse or minimise climate impacts. So cheer up!

Cry me a river - Part Two

Last week we saw how climate can impact the hydrological cycle, and how this can in turn have disruptive implications for freshwater fisheries. Today we will see how climate change can directly affect ecosystems by influencing nutrient dynamics.

Eutrophication is the process by which a lake or fluvial ecosystem is overwhelmed by an unprecedented influx of nutrients. This can lead to the formation of dense algal blooms on the surface of the water which prevent photosynthesis from occurring in the deeper strata of the water column. In turn, there fewer bottom-dwelling plants can grown, leading to a shortage of food supply for smaller fish, and the effect cascades through the food web right the way to the top predator, often leading to disastrous fish kills.

 Additionally, dense algal blooms can deplete the dissolved oxygen in the water. This can lead to an environment that is unsuitable for fish species, both large and small, that previously populated the ecosystem.

The main cause of eutrophication is the massive influx of nutrients due to human activity. The widespread use of fertilisers and the discharge of industrial and domestic waste in watercourses can lead to increased inputs of nitrates and phosphates. However, scientists are beginning to examine how, if at all, climate change will impact eutrophication processes in terrestrial freshwater environments.

Figure 1 - Potomac River, USA, with dense green cyanobacterial bloom typical of eutrophication

A paper by Ficke et al. (2007) suggests a possible mechanism by which increased global temperatures could augment the process of eutrophication. Warmer temperatures have the potential to increase algal growth and bacterial metabolism. Enhanced growth and metabolic rates provide an opportunity for algal and bacterial populations to explode, leading to scenes like the one above.

Heino et al. (2009) draws attention to the fact that temperature increase will intensify precipitation events (discussed in the last post), which leads to a more intense process of nutrient leeching from fertilised soil and a greater input of nitrates and phosphates into lakes and rivers.

If these predictions are true the implications for freshwater fish stocks are quite severe, with a limited source of food for many established fish species and the increased likelihood of fish kills due to oxygen depletion.

However, the mechanisms are not yet fully understood, and there is much discussion as to whether climate change can actually ameliorate the disruptive process. Research by Schindler (1997) found that climate change coincided with declines in phosphorus levels in certain Canadian lakes. Ficke et al. (2007) suggest that the increased stratification of the water column in response to warmer temperatures could lead to a sequestration of nutrients in the hypolimnion, where they are inaccessible to algae and bacteria that may try to grow on the surface of the water.

Now while this might seem inconclusive, present knowledge suggests that we really cannot give any definitive answers as to how climate change will impact eutrophication processes. The articles looked at in this post suggest that increased temperatures work alongside other factors to determine the outcome. So for the best results we'd best examine lakes and rivers on a case by case basis. Hopefully further research will shed more light on the topic, but the present lack of consensus is testament to the complexity of the matter at hand.

Cry me a river - Part One

So far we've focused on the implications of climate change on marine fisheries. In today's post we will look at the problems faced by freshwater environments, mainly rivers and lakes, and their ecological assemblage.

It's important to recognise that the effects of climate change on freshwater environments are not exactly the same as those acting on marine fisheries. As discussed in previous posts, changes in chemical dynamics are responsible for damage to coral reefs and fish stocks. Rivers and lakes on the other hand are susceptible to changes in the hydrological cycle. This is a very broad topic in itself, and there is a great blog you can visit to find out more if you're interested.

First of all, increased inland temperatures can have a direct effect on lakes and rivers. Obviously, it can intensify aridity and therefore lead to a higher dry season mortality of fish and other important species in ecosystem. Additionally, many species have a particular acceptable range of temperature (known as their temperature niche) and any change in temperature can drive fish species out of their habitats. Worse still, it can lead to the succession of more competitive invasive species, parasites and pathogens which threaten 'native' species.

Furthermore, increased temperatures can lead to changes in the mixing of lake water. Mixing regimes are highly important due to the internal circulation of nutrients. Lake Tanganyika, occupying territory in the Democratic Republic of Congo, Tanzania, Burundi and Zambia, has experienced a slowdown in the mixing of water strata. This has meant that nutrients are no longer resuspended as much, leading to a decline in plankton species assemblages and a 30% decrease in the yield of planktivorous fish.

Figure 1 - Lake Tanganyika

The complexity of the hydrological cycle means that it is quite difficult to predict with certainty how it will respond in the face of future temperature increases. A policy briefing by the WorldFish Center suggests that continued climate change is likely to lead to increased seasonal and annual variability in precipitation patterns. In turn, this is likely to unpredictable flood and drought extremes that can potentially have severe impacts on inland fisheries. These changes mean that Bangladesh, a country that relies on fisheries for 80% of its protein intake, is likely to see an increase of 23-39% of areas prone to flooding. Flooding is a particular issue as the high wet season discharge and low dry season flows can lead to a disruption of the spawning season of various species.

An extensive analysis of historical data of salmon ecology in the Thames, the Severn, the Wye, the Lune and the Dee suggests that the increase in frequency of summer droughts and winter floods due to climate change are likely to lead to lower survival rates and a diminished abundance of the species.

The importance of the climate on hydrological processes is therefore quite obvious.

Plenty more fish in the sea? - Part Two

Figure 1 - The Carbon Cycle (source: WBGU 2006)

As mentioned last week, ocean acidification is another problem faced by many of the world's fisheries. Central to understanding this phenomenon is the carbon cycle, represented here in the image. The numbers in bold represent carbon reservoirs in gigatonnes (Gt), while the other numbers represent carbon fluxes in gigatonnes per year. We can see that together, the intermediate/deep ocean and the surface layer lock up about 38,000 Gt and that the largest annual influx to the oceanic store comes from the atmosphere. The flux dynamic between the surface and ocean is driven by different partial pressures of CO2 between the atmosphere and seawater, leading to an annual uptake of 2 Gt of carbon by the ocean each year - a figure that amounts to about 30% of annual anthropogenic emissions.

When it has been exchanged and passed into the ocean, CO2 is able to react with other chemicals. The ocean establishes a reversible equilibrium reaction involving CO2:

Figure 2 - Carbon in the ocean

 Carbon dioxide reacts with carbonate ions and water in the ocean to form acidic bicarbonate ions. With a continuous influx of CO2 into the equation due to anthropogenic carbon emissions, the partial pressure of CO2 increases and the equation equilibrium shifts towards bicarbonate, producing more of the acidic ions

Now while slight changes in ocean pH would not have direct impacts on fish, it is important to consider the implications elsewhere in the ecosystem. Increased acidity is predicted to disrupt planktonic crustacean communities, which would have a knock-on effect on the juvenile fish and fish larvae that rely on them for food. Likewise, bivalve molluscs and echinoderms are forecast to decline in the face of changing acidity. They provide a source of food for a variety of adult fish species. With both juvenile and adult populations at risk, it's clear that ocean acidification puts significant pressure on fish populations. It is believed that to date acidity has gone from 8.2 to 8.1 - an increase of 30%.

Additionally, ocean acidification leads to problems with coral reefs too. The process of calcification, which is instrumental in the construction of coral skeletons, is impaired by the increased CO2 concentrations. This happens because higher CO2 concentrations shift the equilibrium in the above equation towards the right, in favour of bicarbonate and at the expense of carbonate. Consequently, coral reefs are less able to expand, and we know from the last post how important reefs are in marine ecology.

So far, we've looked primarily at the implications of climate change for marine fisheries. Next time we'll consider the impacts on fluvial fish stocks - that's salmon to look forward to.

Plenty more fish in the sea? - Part One

As I write this, the world's foremost climatologists, ecologists and earth scientists are meeting in Berlin to decide whether or not the 'Anthropocene' should become an actual epoch. Originally conceived by Eugene F. Stoermer in the 1980s, the specifics of this anthropocentric period are highly contested. William Ruddiman, who will be making his case at UCL this coming Tuesday, asserts that humans have impacted the environment for thousands of years longer than the couple of hundred years since the industrial revolution usually cited as the Anthropocene. Regardless of the timescale, one thing is certain - present environmental conditions are such that human agency is an increasingly important factor and we are already beginning to see the effects of anthropogenic climate change.

A report by the International Fund for Agricultural Development (IFAD) identifies temperature as one of the climate change impacts on fisheries. Fish and most marine non-mammals are poikilotherms - they have no internal mechanism for heat regulation and are reliant on their surrounding environment to maintain an optimal body temperature. Therefore as climate change proceeds to increase ocean temperatures, fish and other organisms will migrate north to cooler waters in order to secure their optimal temperatures. An analysis of 50 fish species in UK and Irish waters found that 70% responded to increasing temperatures by changing their distribution, with an increase in typically warm-water species and a marked decline in colder-water species. In this scenario there will be winners and losers with fish migrating to higher latitudes, providing a larger marine stock. By contrast, tropical and warmer latitudes will experience a decline potentially threatening the livelihood of some of the poorest coastal communities.

Rising sea surface temperatures also poses a threat to marine habitats, which in turn disturbs fish ecosystems. Coral reefs provide a habitat for a variety of fish species, particularly in the vital juvenile stage of the life cycle. However, as temperatures rise they become increasingly susceptible to the process of coral bleaching and fish species are severely limited in their choice of spawning ground. On top of the pressures of temperature rise, coral reefs are vulnerable to the threat of ocean acidification, which will be discussed in the next post.

Welcome! You've come to the right plaice...

The importance of marine ecosystems in global food supply today is undeniable. Marine fisheries are assessed as contributing 80 million tonnes of protein a year to human diet, and offer a livelihood for 8% of the world's population. Fish is particularly important in developing countries, acting as a vital source of protein for growth and development where meat is otherwise unavailable or expensive. But demand for this vital food source is not static - demand for fish is forecast to increase in line with the expanding population and improving levels of economic development.

Fisheries as a food source have the potential to achieve the resource sustainability in food supply that we desperately need. This diagram from National Geographic represents the quantity of feed mass required to produce a pound of body mass. At 1.1 pounds of feed, fish is clearly more efficient than chicken, pork or beef and seems a suitable candidate for a resource-stretched future. However, while a mass global dietary shift towards fish may be efficient, it is also difficult to attain under present circumstances. And let's face it - who wants to eat nothing but fish?

The pressures that climate change poses to fish stocks and global fish supply are still not fully understood, and will only make a bad situation worse. Fisheries are in quite dire straits due to human over-exploitation coupled with a limited understanding of marine ecosystem dynamics. Global marine catch peaked in 1996 and has been in decline ever since, and it is now thought that as many as 64% of global fisheries are in a state of over-exploitation.

It's clear therefore that if fish is to remain a staple source of protein and nutrients in the human diet it is important to understand the threats posed to global fish supply and the actions we can take to limit them. The purpose of this blog is not to offer a comprehensive solution to the problems facing fisheries - I can assure you that I'm hopelessly under-qualified for such an undertaking. Instead, over the coming weeks this blog will examine the science behind climate change and fisheries as well as exploring proposed and implemented management strategies. And of course, no geographical inquiry will be complete without a healthy dose of case studies, so you can look forward to (I use that phrase reluctantly) analyses of marine and fluvial ecology.

Please feel free to comment and contribute, and hopefully we can start insightful discussion regarding this crucial resource!