If current global trends continue, the loss of fish and seafood will threaten food supplies and the environment, according to the most exhaustive study to date on the subject, published in yesterday’s issue of the US journal Science.
“Our analyses suggest that business as usual would foreshadow serious threats to global food security, coastal water quality, and ecosystem stability, affecting current and future generations,” the international team of ecologists and economists wrote in Impact of Biodiversity Loss on Ocean Ecosystem Services.
The four-year analysis was the first to study all existing data on ocean species and ecosystems and synthesise them to understand the importance of biodiversity at the global scale.
“Whether we looked at tide pools or studies over the world’s oceans, we saw the same picture emerging,” lead author Boris Worm of Dalhousie University, in Canada, said in a statement.
Dr Worm said the disappearance of species from ocean ecosystems had been accelerating.
“Now we begin to see some of the consequences. For example, if the long-term trend continues, all fish and seafood species are projected to collapse within my lifetime — by 2048,” Dr Worm said.
“In losing species, we lose the productivity and stability of entire ecosystems. I was shocked and disturbed by how consistent these trends are — beyond anything we expected.”
Twenty-nine fished species were considered “collapsed” in 2003, that is their catches have declined by 90% or more, he said.
“It is a very clear trend and it is accelerating,” he added.
The study revealed that the loss of marine biodiversity hurt so-called ecosystems services — the goods and functions essential for a growing human population.
It also showed that the loss of one species accelerates the unravelling of the overall ecosystem, while, conversely, every species recovered adds significantly to its productivity, stability and ability to withstand stresses.
The researchers determined that the problem is far greater than losing a key source of food. The effects of damage to the oceans included a decline in water quality by biological filtering and the protection of shorelines by marine species.
The loss of marine diversity also appeared to increase the risks of coastal flooding, harmful algal blooms, oxygen depletion and fish kills.
“Through this research, it became clear to me that we hardly appreciate living on a blue planet,” Dr Worm said. “The oceans define our planet and their fate may to a large extent determine our fate.”
The researchers collated data covering 1,000 years of marine history across 12 coastal regions in North America, Europe and Australia, as well as the results of 32 marine experiments that manipulated species diversity on small, local scales.
“The data showed us it’s not too late,” said Dr Worm. “We can turn this around. But less than 1% of the global ocean is effectively protected right now.”
The authors concluded that an ecosystem-based management approach towards restoring marine biodiversity — including integrated fisheries management, pollution control and creation of marine reserves — was essential to avoid serious threats to the global ecosystem.
A STUDY published by Dalhousie University in Halifax, Canada, has announced that if current international fishing levels continue, the world will “end up with no seafood” in less than 50 years.
The estimated date at which stocks of commercial fishing species will collapse due to overfishing.
“Biodiversity is a finite resource,” says Dr Boris Worm, who led the Dalhousie study.
“We can predict when we are going to run out of species.”
The percentage of seafood species that have collapsed (ie their catch has declined by 90% or more) in the past 50 years.
The percentage decline in global fishing yields since 1994.
The annual per capita consumption (in lbs) of fish and shellfish in Japan, the world’s biggest fish-eating nation.
The average per capita consumption in the US is 16.6 lbs.
The weight of fish, in metric tonnes, caught each year by Chinese fishermen.
The number of marine areas worldwide that are officially protected to prevent overfishing.
These areas have, according to the Dalhousie report, seen “dramatic” improvements in biodiversity and regeneration of fish stocks.
The percentage increase in biodiversity witnessed in the protected areas above.
The percentage area of the world’s oceans that is currently protected against overfishing.
The annual worth, in dollars, of the worldwide fishing industry.
The number of people worldwide who are dependent on fishing for their livelihood.
The number of people worldwide for whom fish is the main source of protein.
The number of Large Marine Ecosystems (LMEs) in the world.
LMEs are regions of ocean around the coastlines of the world’s continents. They account for more than 90% of the world’s fish catch.
The weight, in lbs, of the largest tuna ever caught — a bluefin tuna caught off Nova Scotia in 1979.