Fisheries' Production Fast Depleting

Some of the impacts are already being felt as reflected by changes in the distribution of fish species in oceans. While the stocks of warmer water species are expanding, those of the colder ones are contracting.

Besides, the rising acidity (salinity) levels in the seas as a result of the climate change are believed to have negative effect on many coral reefs and calcium-bearing organisms.

This has been stated by the United Nations Food and Agriculture Organisation (FAO) in a recent scientific symposium on climate change and marine fisheries held at its headquarters in Rome. The event was aimed at discussing the challenges that climate change posed to the marine fisheries and the millions of people who depended on it for food and income.

The global food body has pointed out that the wild capture fisheries are fundamentally different from other food production systems in its linkages and responses to climate change and in the food security outcomes that result from them, reports Business Standard.

Unlike most terrestrial animals that constitute the livestock sector, aquatic animal species used for human consumption are ‘poikilothermic’, meaning their body temperatures vary according to ambient temperatures.

Any change in habitat temperatures (warming or cooling of sea waters in which they live) significantly influence their metabolism, growth rate, productivity, seasonal reproduction, and susceptibility to diseases and toxins, the report points out.

With global warming, the waters of oceans are also warming up though there are considerable variations in different geographical regions and at different times. Warming has been more intense in surface waters but is not exclusive to these. The Atlantic Ocean has shown particularly clear signs of deep warming. This is causing changes in the distribution of the fish species.

“This is likely to also result in significant changes in fisheries’ production in different seas. The impact would, of course, vary in different regions. For communities that heavily rely on fisheries, any decrease in the local availability or quality of fish for food or increase in their livelihoods’ instability will pose even more serious problems,” the FAO has cautioned. The countries with limited ability to adapt to the changes, even if located in low-risk areas, are equally vulnerable, it adds.

Fisheries and aquaculture play an important role in providing food and generating income. About 42 million people work directly in the fisheries sector, majority of them being in the developing countries. Besides, millions of others work in the associated processing, marketing, distribution and supply industries.

Aquatic foods have high nutritional quality, contributing 20 per cent or more of average per capita animal protein intake for more than 2.8 billion people, mostly in the developing countries. Fish is also the world’s most widely-traded foodstuff and a key source of export earnings for many poor countries. The sector has particular significance for small island states.

This apart, the changes in the ocean salinity have already been observed to occur, which would affect other forms of aquatic life, notably the coral reefs. While the water salinity is on the rise in the near-surface waters in the more evaporative regions of the world, it is decreasing in the high latitudes due to greater precipitation, higher run-off, ice-melting and other atmospheric processes related to the climate change, the FAO says.

“The oceans are generally becoming more acidic, with probable negative consequences to many coral reefs and calcium-bearing organisms”, it adds.