Eiffel Over

Tag: OverFishing

  • Desertification versus dessertification

    Desertification = a real word that refers to the process where fertile land becomes desert, typically due to drought, deforestation, or poor land management. It can also be used more broadly to describe when a population of living things becomes so small that it struggles to sustain itself.

    Dessertification = a word I’ve just made up to describe an abundance of cake.

    Yesterday I talked about overfishing leaving fish populations so sparse that they can barely survive. When a population is reduced to such small numbers, it may become almost invisible. The creatures that remain may live in small, isolated pockets that are vulnerable to disease, and don’t benefit from much genetic variation. Such populations are on the brink of local extinction. 

    But populations in a desertified state can slowly come back into a state of thriving. One way to help them do this is by finding ways to connect together isolated pockets. Connecting to smaller populations creates a larger one with the potential for greater genetic variation, and the ability to move further should environmental conditions change. Both of these increase the resilience of the population. 

    Here I am going to leap from talking about fish to butterflies and people.

    When I first visited Hazel Hill Wood in 2008, it was to take part in a butterfly conservation activity. Our task was creating open corridors through the wood that would allow populations of butterflies living on either side of the wood to mix. As we were told, butterflies don’t like flying through dense, dark, cold woodland. So the wood was effectively a barrier between these two populations. But creating wide openings in the wood lets sunlight in and provides a pathway that the butterflies can follow. Connecting the populations builds their resilience, and today the wood is rich with a wide range of species of butterflies fluttering by. 

    Doing the work of conservation also brings people together. During Covid, the wood was a place where people come together, out of isolation, to form community and build resilience. 

    It is pleasing to think that this work of countering desertification, be that of butterflies or sense of community, is fuelled at tea time by an abundance of cake. Dessertification indeed.

  • No more fish in the sea

    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.