ICES Scientist Believes Climate Change Affecting Fish Stocks
Climate change acts directly on productivity of commercial fish species by altering growth, reproduction and other aspects of life history, either positively or negatively, renowned scientist Keith Brander said recently.
Brander, Project Coordinator, International Council for Exploration of the Seas, said the frequency and intensity of extreme climate events was likely to have a major impact on future fisheries production in both inland and marine systems.
‘The effects of fishing and of climate interact because fishing reduces the age, size and geographic diversity of populations and biodiversity of marine ecosystems, making both more sensitive to additional stresses such as climate change,’ he said in his keynote address at a seminar on impact of climate change on marine ecosystems and fisheries.
Brander pointed out that since the industrial revolution in the 19th century, increase in greenhouse gases has resulted in a sharp rise in global temperature, ‘whose effects on marine biota can be detected now.’ He said the rising Carbon dioxide level and consequent acidification of oceans was having an impact on metabolism and calcification in many organisms, with damage to vulnerable ecosystems like coral reefs.
‘We depend on the oceans and coastal seas for many ecosystem services – supporting, provisioning, regulating and cultural- and there is real cause for concern that these services will be damaged and degraded by climate change,’ he said. Most studies of long-term changes and climate impact to date have come from temperate parts of the Atlantic and Pacific. There was the need for matching information from tropical areas, particularly in the Indian Ocean.
Brander also said climate change is not the only pressure which humans impose on marine environment. Pointing out that there were many stresses on the marine systems, he said fishing, habitat degradation, pollution and introduction of new species also has many undesirable consequences and they also interact with each other. In coastal and inland waters, there are also effects of changes in land use, damming, flood control and alteration of waterways,he said.
He said the species are moving into cold water and that might be the reason why fishing activity is happening in deeper areas. Brander said the recent changes in distribution and productivity of a number of fish species could be ascribed to regional climate variability.