Issues Magazine

Aquatic Biodiversity and the Livelihoods of Fishers in Developing Countries

By Stephen Hall

An understanding of all levels of biodiversity is needed to address poverty and hunger in developing countries, including that of people who rely on fishing or fish farming to live.

In 1992, representatives from 172 govern­ments met in Rio de Janeiro for the United Nations Conference on Environment and Development (UNCED) – also known as the Earth Summit. At this meeting they agreed upon and opened for signature the Convention on Biological Diversity, one of our most significant, wide-ranging and far-reaching environmental conventions. Eighteen years later, as we celebrate the International Year of Biodiversity, it is a fitting time to reflect on how our understanding of biodiversity has developed and how important it is to our lives.

Biodiversity is a term used to describe variation in biological and ecological systems. The variation most of us probably think about when we hear the word is the difference in the number of species that can be found in different places. Most people appreciate, for example, that a hectare of coral reef or tropical rainforest contains many more species and is, therefore, more biodiverse than a hectare of arctic tundra. Animal and plant ecologists spend considerable effort estimating the number of species in different areas, and we continue to refine our picture of where the global hotspots in species diversity can be found.

But while the number of species in an area is an obvious and important focus for those interested in biodiversity, other components at different levels of biological organisation also demand attention. Geneticists, for example, can study the variability in the genetic make-up of different populations of the same species, while community ecologists often consider how many different types of systems (e.g. forests, meadows, lakes, rivers) a landscape supports.

Understanding and conserving biodiversity at all three of these levels – genetic, species and ecosystem – is vitally important for many reasons. For those of us involved in trying to help the poor of developing countries escape poverty and hunger, they all demand attention. Using examples of people who depend on fishing or fish farming for their food and livelihood, this article will illustrate why.

Species Biodiversity

First, let’s consider species biodiversity, taking an example from the distinctive ecology of tropical rainforest rivers in equatorial Africa that support high levels of fish and other biodiversity.

Nouhou Boro lives in a small village in the Lower Guinea rainforest in Cameroon. It is a hot, humid environment. When he was a child he used to catch fish from the streams for the elders in return for a little extra food and some pocket money. The water was clear and the colour of tea from the decaying leaves that fell from the trees above. But the trees are gone now. They were cut down as logging became a profitable business for some in Cameroon, though his village never saw the benefits. The streams and rivers filled with mud, the shade was lost, the temperature rose and his fish, deprived of enough oxygen, died and disappeared.

He’s grown up now but he’s still a fisher. He has joined a project that encourages the harvest and culture of small freshwater fish from the forest streams to sell as “ornamental” fish for the aquarium trade. There is strong demand from Europe, America and Asia for these fish, but they have been in short supply due to the difficulty involved in their capture, confinement and transport, and the difficulty that overseas commercial breeders have had with their reproduction in captivity.

But let him continue the story in his own words:

This did not use to be a very profitable business as most of the fish died when taken to the market and the price we received per fish was tiny, only 5% of the final sale price paid to the buyers, I’ve heard. But now things are very different. We’ve learnt to create holding ponds where we can store the fish we catch and keep them healthy until the buyer arrives. We’ve learnt how to breed some species so that we don’t have to hunt for them in the forest streams and deplete our natural resources. We’ve set up a community of fishers so that we can negotiate better prices with the merchants. Our small fish now make good money. But we can only depend on this income if our supply, in the forest, remains in good condition. So, as a community group, we lobby the local government to prevent the loss of our forest so our livelihoods remain protected.

As the financial value of the natural resource – the biodiversity of the natural fish stock – becomes clear, an incentive is created for appropriate management of the riverine ecosystem to maintain the unique environmental characteristics that permit these species to survive, to reduce pollution from pesticides and insecticides, and to reduce silting from logging and development. Empowering those in favour of the sustainable use of natural resources has been a major contributor to increased local interest in conservation of rainforest rivers in Africa.

Genetic Biodiversity

Now let’s turn to genetic biodiversity.

Nabulungi Jakande is a farmer in Uganda. One of the species she farms in her aquaculture pond is Nile tilapia – an important food fish for her family’s domestic consumption. She and millions like her could produce many more fish if the quality of the fingerlings (baby fish) she needs was improved. Fortunately, although one tilapia might look just like the next, they are as different genetically as you are from your neighbour. It is this genetic variation that allows populations to evolve over time and adapt to environmental changes.

If temperature or salinity increases, for example, individuals that have temperature- or salt-tolerant genes will be able to grow and reproduce more easily and leave more offspring than those who do not have the beneficial genes. If environmental conditions do not change again, over many generations the proportion of individuals in the population with these beneficial genes will increase and constitute the majority. This is the basic process of evolution by natural selection – it depends critically on the genetic variation in the population.

Fortunately, we can use this variation to breed fish selectively to increase the prevalence of desirable genes in the farmed fish population. Building on decades of lessons learned from selective breeding in plants and terrestrial animals, we can use such genetic improvement programs to develop fish with features such as, for example, faster growth, enhanced immunity or improved flesh texture. Such programs have been tremendously successful.

For example, genetically improved farmed tilapia show a gain in live weight of at least 64% compared to the founder population without any deterioration in its survival rate. It is work like this that promises a better future for Nabulungi Jakande and her family and millions of other fish-farming communities.

Although the results of breeding programs can be spectacular, without careful management it is easy to run into problems. This is particularly so when breeding with a small population of fish, where interbreeding over many generations weeds out many genes that may be useful later on if conditions change. To maintain the success of these programs, it is therefore vital that we look after wild fish species populations in as many different locations as possible so that we continue to have access to the full range of genetic variation that nature can offer.

Ecosystem Biodiversity

Finally, let’s consider diversity at the ecosystem level, a subject of study that is now revealing how vitally important it is to preserve the great variety of habitats we find on Earth. Ecologists now realise that ecosystems provide many essential services that we depend upon.

For the people of the Solomon Islands, the services provided by mangrove forests and coral reefs are especially important. Not only do they provide vital products like fish, wood and sources for several medicines but also they play a key role in protecting the coasts from storms. Mangrove forests also serve as filters for fresh water that runs into the sea, keeping coastal oceans healthy, and as a sink for carbon to help combat climate change.

In fact, this role as a carbon sink is now turning into a money-making opportunity for poor people in the Solomon Islands, allowing them to earn an income that they may invest in education, health and conservation. Like all plants, mangroves take up carbon dioxide from the atmosphere and store, or sequester, the carbon in their tissues. Mangrove forests sequester large quantities.

Conserving and replanting these forests may therefore help to mitigate climate change by absorbing and removing one important greenhouse gas. This means that we can use forests in the global market for carbon offset credits. Buyers offset their own carbon emissions by rewarding owners of forested land for keeping their forests intact and providing this important ecosystem service.

Research projects, such as one in the Solomon Islands funded by the Australian Agency for International Development sit at the nexus of research on climate change, biodiversity conservation, payments for environmental services and poverty alleviation. As the first project to explore opportunities for obtaining carbon credits for mangrove protection and rural livelihood diversification in the Solomon Islands, it promises to serve as a practical blueprint for protecting the estimated 50,572 hectares of mangroves nationwide. The direct economic stake that local communities may acquire will provide an incentive for the sustainable use and conservation of mangroves. With the other benefits provided by this ecosystem, local communities should also become less vulnerable to poverty and more resilient to future changes in their environment, including those arising from climate change.

These examples illustrate just a few ways in which nature acts as the great provider and the great recycler, and show why understanding and protecting biodiversity is so vital. We all depend on biodiversity in a myriad of ways for our well-being. It is not only well-being from the products and services biodiversity provides that matters. We must also consider the cultural and spiritual significance that biodiversity has for many people, and recognise the moral and ethical argument for preserving other organisms.

We, as the species that currently alters the environment the most at the expense of others, should take more regard of our activities and realign our priorities to take other species into account, especially those that we have put in danger of extinction. We need to continue to make use of biodiversity at all its levels, but in a responsible and sustainable manner so that future generations can enjoy its benefits.

The WorldFish Center is an international organisation with a mission to reduce poverty and hunger by improving fisheries and aquaculture. We are one of 15 centres of the Consortium of CGIAR (Consultative Group on International Agricultural Research) Centers, carrying out research-for-development in partnership with a wide range of government and non-governmental agencies in developing countries. Our 250 staff are working in more than 25 countries.

Because our mission is predicated on maintaining ecosystem health and the natural resource base through sustainable use and conservation of biodiversity, many of our projects contribute to achieving the goals of the Convention on Biological Diversity.

For more information on the WorldFish Center visit