(CNN) -- The world's appetite for fish is now at an all time high according to the United Nations.
Figures from the U.N.'s Food and Agriculture Organization (FAO) state fish is currently the most-traded food commodity, worth around $102 billion in 2008.
But as our appetite for fish increases, the world's fish stocks are becoming increasingly overexploited and depleted, which "gives cause for concern" the U.N.'s 2010 State of World Fisheries and Aquaculture report has stated.
Put simply, we are eating too much, says Dr Daniel Pauly, marine biologist and professor at the University of British Colombia.
"The pressure we are imposing on the world's fisheries is excessive. Either we are eating too much or we are too many," he said.
But he added: "Fishery science is very much divided in this debate."
"Three or four years ago there was wide consensus that fisheries were doing very badly, now again it has become a contentious issue, much like talk on global warming," he continued.
Much of the debate is focused around annual figures of global fish catches, which reached a peak of 86.3 million tons per year in 1996. Since then there has been a decline, with 2008's annual fish catch dropping to around 79.5 million tons.
While some scientists suggest the downward trend shows a move away from over-fishing and a replenishing of fish stocks, others believe the data proves fish stocks are already overexploited or depleted.
Pauly believes the change in fish catches and a spike in fish consumption can be explained, in part, by the expansion of fishing operations into new waters over the last 50 years.
"Europe like the U.S. and Japan now get most of their fish from the developing world," he said.
"As the European stock was depleted, Europe simply went south and expanded. We find the same sort of expansion in Japan and the U.S., so instead of being sustainable, we have just moved on. The logical end of this, and we have begun, is fishing krill in Antarctica. " he continued.
But he said: "This southward expansion seems to be at an end, because there are no more waters to be conquered.
While scientists disagree on the current state of fisheries worldwide, the FAO has made its conclusions clear, stating global fishing catches will not be able to increase "unless effective management plans are put in place to rebuild over-fished stocks."
As Pauly states: "The need to rebuild instead of expand is not rocket science. If we do not rebuild our fisheries, how will we ever produce a decent yield?"