Somehow the topics of my posts have returned to the subject of the sea. It is apparently a rich subject to trawl. Sorry, I couldn’t resist the pun, but it is exactly to trawling that I am heading.
Yesterday I used Donella Meadows’s fish stocks example to show how humans can harvest a living resource while enabling it to thrive. A key to enabling this system to work is the balancing feedback loop between supply and the people doing the harvest. When the catch gets too low, the boats go home, and the fish can restore their population.
But what happens when that balancing feedback loop is broken?
Let us imagine an entrepreneurial fisher who, noticing that their catch was diminishing, decides to invest in a much bigger net. Now their catch goes up and it is worthwhile for them to stay at sea for longer. Other boat captains do the same, and the fleet stays out much longer.
Now, rather than the fish population having time to replenish itself, it is further depleted. When the fish are further apart, their rate of reproduction diminishes.
Here, trawling is breaking the balancing feedback loop between supply and harvesters. So, instead of stopping, fishing continues and the population becomes so low that it is not able to grow back. It has become what is known as a ‘desertified state’, a vulnerable situation in which a living system can no longer thrive.
Clearly, this is a simplified version of a much more complex system. But hopefully it serves to illustrate that in thinking about how we scale up options, we need to think about how we might inadvertently be breaking the feedback loops that enable our activities to operate within the living system’s limits.