The world has grown more dependent on fish for food. But the U.N. Food and Agriculture Organization says climate change is putting fisheries and fish farms at risk.
Fisheries are defined as areas where fish are caught, processed and sold. Ninety percent of the world’s inland fisheries are located in Africa and Asia and help to ensure food security in poor countries.
Dr. Tim Daw is co-author of the new FAO report called Climate Change Implications for Fisheries and Aquaculture. He’s also a lecturer at the School of international Development at the University of East Anglia in Britain.
“Fisheries are hugely important, particularly in developing countries. And estimates are half a billion people rely on fisheries for their livelihoods. So they are important as a source of food and they provide us with very high protein,” he says.
Most fisheries are commercial to a certain extent.
“They (fisheries) are often available in places where other forms of development are not available. So often in remote coastal areas you’ll see fisheries being their economic engine behind driving development and growth,’ he says.
Africa and Asia
“Inland fisheries are particularly important from a food security perspective,” he says, “Often those fisheries are available in lakes or rivers or remote rural areas.”
The fisheries, however, are very sensitive to temperature changes for many reasons.
“So if you were to talk about inland fisheries, certainly what is projected by the climate models is a change in the distribution of rainfall and change in the extent of glacial melt water. So very large changes in the way in which rivers and lakes flow around the continents and fluctuations in lake levels,” he says.
For example, if the level of a lake drops sharply during the dry season, fisheries may be forced to shut down.
“With increased fluctuation in rainfall levels, increased frequency of droughts or extreme wet weather events, we may see further disruption of these systems,” he says.
Fish feel the effects
“Fish are themselves sensitive to temperature changes,” he says, “There are various pathways to do with how much oxygen is dissolved in the water, the thermal tolerance of different species and also the thermal tolerance of the ecosystems on which they rely.”
That could disrupt the food chain for fish and in turn affect the size of the catch.
What’s the rush?
While many urgent warnings about climate change are being made now, the effects are not always immediately seen. The FAO report says, “Significant negative impacts will be felt across 25 percent of Africa’s inland aquatic ecosystems by 2100.”
Daw says, “There’s a big delay in the systems, so we have to be very aware of what we do now. How that will have impacts in the future and on future generations,’ he says.
Nevertheless, Daw says the signs of climate change are here now.
“If we don’t take action now it will be too late in the future when the effects start to happen. But we are already seeing impacts,” he says.
Climate can fluctuate from year to year, so it may be difficult to blame climate change for any particular weather-related event. But…
“What we can say is that the models predict that these extreme events will become more frequent. And a great example was the very strong El Nino event, which happened in 1998,” he says.
It was blamed for extensive coral bleaching and death of coral reefs in the Indian and Pacific Oceans and the Caribbean.
“That was a quite devastating, worldwide measureable impact of high sea surface temperatures on a marine ecosystem. And in many nations in the developing world there are marine fisheries based on coral reef ecosystems,” he says.