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Blog Action Day 2011: Freshwater ecosystems and sustainable food

October 13, 2011

Sunday 16th October is Blog Action Day, a global event where hundreds of blogs join forces to promote a unified message.  Last year we wrote about “Water – discussing the need for increased perception and understanding of freshwater ecosystem conservation.  This year, the theme is “Food”.

Freshwater ecosystems: a vital source of nutrition and food security

Global rivers, lakes and wetlands contribute significantly to global food supply.  The food system uses 70% of available global freshwaters (Aiking, 2011).A 2010 United Nations Environment Programme report by Patrick Dugan and colleagues showed that inland freshwater fisheries provide over 33% of the world’s small scale fish catch, providing valuable food security, improving rural livelihoods and employing over 60 million people.  Freshwater food systems also have the potential to promote gender equity and empower women: Dugan and colleagues suggest that over 55% of people employed by freshwater fisheries are female.

Fish is rich in protein, omega 3 and amino acids and often low in fat.  The supply of fish is as such globally important for human nutrition.  This is especially important in Africa – where around 100 million people regularly consume freshwater fish – and the Mekong Basin in Southeast Asia – where 60 million people get their main source of protein from freshwater fisheries. Importantly, Christophe Béné and colleagues at the Food and Agriculture Organisation published a report in 2007 suggesting that fish and other food produced by freshwater ecosystems often act as a ‘safety net’ for the poorest households when agricultural harvests fail.

Giant gourami, a species popular for aquaculture in Thailand. Image: Wikipedia

Aquatic Plants and other non-conventional freshwater food sources

Aquatic plants such as wild rice (Zizania palustris); Spirulina Algae; edible aroid – Araceae;  and taro – Colocasi,  contribute in some way in alleviating human hunger in some of the lesser developed regions of the world. In addition, a 1998 World Conservation Monitoring Centre report suggests that frogs, crustaceans, molluscs, crocodilians, waterfowl and even manatees provide protein to some cultures.

Freshwater fisheries as a provisioning service

Scientists and environmental managers are increasingly using an “ecosystem service” approach to demonstrate and explain how humans benefit from the multiple services provided by the natural environment.

Freshwater ecosystems not only provide food, but a range of other important services.  Put simply, these “services” can be categorised as:

Provisioning – e.g. food production, sources of medicine
Regulating –
e.g. pollination, climate and air quality regulation
Supporting –
e.g. nutrient cycling
Cultural –
e.g. providing recreation, ecotourism, education and spiritual values

Houseboat fishfarms in the Mekong Delta, Vietnam. Image: Bill Bradley

How can we sustainably harvest freshwater ecosystems for food?

However, not all freshwater food production is sustainable.  Freshwater food webs are generally less productive and more fragile than their marine counterparts, which themselves are showing global collapes.  Fish farming and other forms of aquaculture have spread globally in recent decades, providing incredible levels of productivity and so are often seen as a valuable tool for improving human livelihoods.  However, this productivity often comes at a cost (see the ECASA website for a range of literature and resources on this topic), where inputs such as food and chemicals are leached out into the wider ecosystem along with waste faeces.  In salmon farms across northern Europe, there is also the growing problem of escaped sterile, farmed fish negatively affecting the spawning success of wild fish.  However, efforts are being made to research new sustainable forms of freshwater fish farming.

As the UNEP and FAO reports show, for many people across the world, harvesting wild freshwater fish provides valuable sustenance.  However, as we’ve discussed before, taking even a small number of wild freshwater fish for food from a small ecosystem may have large, cascading effects on the health of the rest of the ecosystem.  This creates potential problems as it reduces how effectively the ecosystem can respond to external threats such as pollution (a concept known as resilience).

The European eel, a prized freshwater food fish. A recent Zoological Society of London study suggested that eel populations in the English River Thames have dropped 98% in the last 5 years, partly due to overfishing. Image: Wikipedia

Freshwater ecosystems and food sustainability

With all this in mind, how can we sustainably use the food provided by our freshwater ecosystems?  Given the potential problem of overfishing wild populations coupled with the negative environmental effects of some aquaculture programs it’s clear a balance must be struck between food production and sustaining healthy freshwater ecosystems.  Our rivers and lakes are dynamic, interconnected, living systems rather than an inert resource base to be exploited.  We need to think about the impact of taking resources from freshwater ecosystems on the health of the wider ecosystem.

A such, we suggest that we need for an ecosystem approach to managing our lakes and rivers.  Taking this approach, where the production of food is seen as an output dependent on the health of the wider ecosystem,  we can look forward to more sustainable freshwater food systems.   Freshwaters provide essential resources such as food for us, but we must value them as more than simple resource bases.  The sustainable provision of food from our freshwaters depends on ecosystem health, integrity and diversity, all things we at BioFresh see as vital to conserve.

What you can do:

  • Follow Blog Action Day on Twitter (@blogactionday11) and post using the hashtag #BAD11
  • Read the variety of blog posts from writers around the world through the Blog Action Day website
  • Publish your own blog on the subject and submit it to the Blog Action Day site
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