Cassandra has moved. Ugo Bardi publishes now on a new site called "The Seneca Effect."

Thursday, January 22, 2015

Sandeels: another Seneca cliff




Once you start looking for "Seneca Cliffs" in the exploitation of natural resources, you find them all over the scientific literature. This is my latest find of a production curve where decline is much more rapid than growth: the landings of sandeels. If you don't know what a sandeel is, here is one: 



In the report (2007), where I found the curve shown above, the authors discuss the causes for the collapse of the fishery, especially in view of climate change. They don't seem to arrive to any definitive conclusion and they don't use the dreaded term "overfishing". But from the fact that trawlers were used in this fishery, I think it is clear that the fish stock was being destroyed in a process similar to the one that led to the collapse of the whole UK fishing industry. The more resources were aggressively thrown at trying to maintain production, the more the fish stock was depleted. The end result was the rapid collapse observed.

So, as in several other cases, we have a classic example of the "Seneca Collapse", that is a production curve where decline is much more rapid than growth. Below, you can see the Seneca curve as shown in a simulation carried out by system dynamics that takes into account the increased capital expenditure in fishing equipment (the model is described here). 



As Seneca said, "the road to ruin is rapid", indeed.



Who

Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)