I wonder if the editors at Science Daily understand just how priceless their seemingly innocuous reprint Oysters Could Rebound More Quickly With Limited Fishing and Improved Habitat truly is. Even if they don't, you will understand it in a few moments. We're dealing with the dwindling oyster populations of Chesapeake Bay.
June 13, 2013 — A new study shows that combining improved oyster restoration methods with limits on fishing in the upper Chesapeake could bring the oyster population back to the Bay in a much shorter period of time. The study led by Michael Wilberg of the University of Maryland Center for Environmental Science's Chesapeake Biological Laboratory assessed a range of management and restoration options to see which ones would have the most likelihood success.
"This new model we developed suggests that oysters should be able to come back if we help them out by reducing fishing pressure and improving their habitat," said Wilberg.
Eastern oysters in the Chesapeake Bay have undergone a drastic decrease in abundance over the past century due to overfishing and disease.
The population is currently estimated to be less than one percent of its historic high, making substantial restoration efforts necessary if the population is to recover.
The team's study shows that if oysters were allowed to reproduce naturally and fishing were halted, it would take between 50 to 100 years for oyster abundance to reach as high a level as could be supported by the Bay. If fishing were reduced to about half its current level, it would take as many as 200 to 500 years to see a healthy population restored to the Bay.
The current oyster population is less than 1% of the original stock. Here we have established the time frame for full restoration of oyster populations in Chesapeake Bay—50 to 100 years if fishing is halted, and 200-500 years if oystering continues at half its current rate.
"The fishery as it has been practiced hasn't been sustainable, and our model helps explain why," said Wilberg. "Oysters just can't replace the shell that has been removed fast enough to keep up."
Oysters are called ecosystem engineers because they build habitat for themselves and other creatures. Oyster harvesting methods, such as dredging and tonging, chip away at the oyster reef and knock it down, spreading the shells over the bottom and making the remaining oysters prone to being covered by silt or moving them to a soft surface where oysters cannot grow.
Since reefs are the place where oysters are born and reproduce, fishing not only removes adults from the population, but also removes habitat essential to their survival.
Here is the quote which makes this article priceless.
"Oysters should be able to rebuild their reefs if we leave them alone," said Wilberg.
"It's an experiment that hasn't been tried yet."
In yesterday's post, we saw that the costs of coping with climate change are going up as the Earth warms. Over the longer term, those mounting costs are bound to negatively affect economic growth, which will affect the amount of CO2 which goes into the atmosphere. For example, the IEA recently reported that "global emissions of carbon dioxide from energy use rose 1.4 percent to 31.6 gigatons in 2012, setting a record..." What the IEA did not emphasize was that the growth rate of CO2 emissions in 2012 was much smaller than it had been in prior years, which indicates that the growth rate of the global economy slowed considerably last year.
This was not due to the costs of coping with global warming—at least, not yet. In fact, building infrastructure to cope with climate change will initially increase nominal economic growth! Jobs will be created, resources brought to bear, and so on.
Let us now consider the lowly oyster of Chesapeake Bay. If we were to leave the oysters alone, the population would rebound to historic levels in 50 to 100 years. But that experiment hasn't been tried yet, presumably because the cost (to some) is considered too high. If there were no cost associated with leaving the oysters alone, then presumably we would do so, for isn't it better to have a thriving ecosystem in Chesapeake Bay than to have the infertile wasteland we have created?
Now let us extend that thought to the oceans generally. I often write about the overfishing and destruction of marine ecosystems, a trend which is truly global in scale. If we were to leave the oceans alone, the health of those ecosystems might be restored to a state last seen 500 years ago (to pick a date) in something like the time frame the oysters of Chesapeake Bay require.
Now let us consider the costs of leaving the oceans alone. On a grander scale, this is the experiment that hasn't been tried. The costs would be mind-bogglingly large. The direct cost of leaving the oceans alone is zero because doing nothing costs nothing.
But the opportunity costs and the general human costs—the indirect costs, the consequences—are literally unthinkable to humans, and therefore far beyond prohibitive as far as they're concerned. The world's fishing industries would be shut down. That's about 150-200 million people. How would all those people stay alive? What about the one billion people whose main source of protein is fish, crustaceans and mollusks?
Now we see why the experiment that hasn't been tried yet has not only not been tried, it will never be tried. If humans can't even leave the oysters of Chesapeake Bay alone, they are certainly not going to be able to leave the world's marine ecosystems alone. Humans have locked themselves in. These terrible dependencies only become stronger as human populations, consumption and wealth grow.
As you think about how the human future will go, carefully consider what I have said here.