Changes in sea temperatures brought in as a result of warming also alters the body temperatures of aquatic species thereby affecting their metabolism, growth rate, reproduction and susceptibility to diseases and toxins, the UN Food and Agricultural Organisation (FAO) said.

Increase in frequency and intensity of extreme weather events such as the El Nino phenomenon in the South Pacific, the warming of oceans and movement of warmer-water species towards the North and South Poles are some of the visible effects of climate change, the FAO said, expressing concern for the fishery industry during a seminar on climate change and marine fisheries in Rome.

There has also been an increase in salinity in near-surface waters in warmer regions, while increased precipitation and melting of ice in cooler areas facilitate the opposite. In addition, the oceans are becoming more acidic with probable negative consequences for coral reef and other calcium-bearing organisms, FAO said.

Fishing communities in higher altitudes, as well as those relying on coral reef systems, will be most exposed to the impact of climate change, the UN food agency said, adding that fisheries in deltas and ice-dominated coasts will be more vulnerable to flooding and erosion due to rise in sea level.

According to statistics available with FAO, some 42 million people work directly in the fishing sector, the great majority of them in developing countries.