I happened upon this article and found it interesting on a number of grounds. The one I'll emphasize here is Pitcher's exposition of "Three Ratchets":
In fisheries, three ratchet-like processes continue to contribute to this erosion of biodiversity and ecosystem integrity.Fishing acts as a selective force on ecosystems by removing long-lived, slow-growing fish in favor of those with higher turnover rates. This process operates both within and among species. When species (or genotypes) become extinct, the past becomes hard to restore, like a ratchet. I term this "Odum's ratchet", recognizing Eugene P. Odum's concerns with human-caused extinctions... local extinctions are in fact the critical process in compromising biodiversity, shifting trophic pathways, and altering habitat for other species...
The second mechanism, termed "Pauly's ratchet", refers to the psychological tendency for us to relate changes in the system to what things were like at the time of our professional debut: accounts of former great abundance are discounted as anecdotal, methodologically naïve, or are simply forgotten. Sustainability as a policy objective, therefore, tends to be applied to a ratchet-like baseline...
"Ludwig's ratchet" is the third mechanism, and refers to the generation of additional fishing power through loans that can be repaid only by sustained catches that, on account of stock depletion, can be generated only by further investment in fleet technology. Ludwig's ratchet leads to overcapacity, the single biggest economic problem in fisheries. Much of the problem has been caused by government subsidies... The catching power of the world fishing fleet continues to expand... (pp605-606)