Global food supply threat from overfishing, study finds
Food supply threat from overfishing, study finds
WASHINGTON: Fewer big predatory fish are swimming in the oceans because of overfishing, leaving smaller species to thrive and double in force over the past 100 years, scientists say.
Kerry SheridanFebruary 20, 2011
Big fish such as cod, tuna, and grouper have declined worldwide by two-thirds while numbers of anchovies, sardines and capelin have surged in their absence, University of British Columbia researchers said.
People around the world are fishing more and coming up with the same or fewer numbers in their catch, indicating that humans may have reached the limit of the oceans' capacity to provide food.
''Overfishing has absolutely had a 'when cats are away, the mice will play' effect on our oceans,'' said Villy Christensen, a professor in the university's fisheries centre.
''By removing the large, predatory species from the ocean, small forage fish have been left to thrive.''
The researchers found 54 per cent of the decline in the predatory fish population had taken place over the past 40 years.
The researchers said despite the spike in small fish populations, the total supply of fish was not increasing to meet human demand.
''We may in fact have hit peak fish at the same time we are hitting peak oil,'' said Reg Watson, a scientist at the university.
Seafood makes up a large part of the global human diet, according to research fellow Siwa Msangi of the International Food Policy Research Institute, who said the rise in demand was largely being driven by China.
Jacqueline Alder from the United Nations Environment Program suggested the world needed a swift cut in the numbers of fishing boats and fishing days.
''If we can do this immediately, we will see a decline in fish catches. However, that will give an opportunity for the fish stocks to rebuild and expand their populations.''