I’m not talking computer networks, either, but the far more difficult to evaluate biological, or ecological networks. How are they best evaluated? Consider this comment on a fishery:
Sustainability also often fails to take into account wider ecological factors. The langoustine fishery in the Firth of Forth in Scotland, for example, is sustainable, but only because so many other species have been fished to extinction and the langoustines no longer have any natural predators, says [Daniel Pauly at the University of British Columbia in Vancouver]. [“Is there any type of fish you can actually eat sustainably?” Graham Lawton, NewScientist (13 February 2021, paywall)]
This strikes me as an example of mistaken metrics. Sure, the one fishery is doing great – at the expense of all the rest. Omit that latter information, though, and the advocate for higher fish limits may win his goal, but at the expense of critical intellectual honesty.
Pauly illuminates another problem, this having to do with proxies:
You also have to consider that fishing vessels are more powerful than they once were, says Pauly. “Even though the biomass has declined, they are able to compensate by finding the few fish that remain, and being able to operate where old trawlers would not be able to,” he says. “The fact that our trawlers maintain catches is not an indication that abundance has remained the same.”
In this case, the proxy is the size of the catch indicating the size, or health, of the population. It’s flawed because the operationality of gathering that data has changed. Again, those trying to make a point in an argument that omits this key information are committing a type of intellectual fraud, if they do so deliberately.
My current preference for a measurement of the health of the oceanic network is biomass as it changes over time, along with some sort of measure of diversity, undefined. This, of course, is damn near impossible to measure:
“Many countries do not have research ships to go to sea and monitor the stocks,” says Manuel Barange, director of the FAO’s Fisheries and Aquaculture Policy and Resources Division. Even when they do, the science is challenging. It requires an estimate of the total biomass of a species within a huge geographical area, and then an assessment of whether that is enough to support the maximum sustainable yield. The margin for error is so large that a stock is considered sustainable even if it is 20 per cent lower than needed for the maximum sustainable yield.
Competition and evolution mean, of course, that fisheries will go up and down and extinct without human interference. These facts make the jobs of ecologist and environmentalist a little more tricky, as the argument cannot be “Oh it’s way down;” the argument must be formulated in terms of long-term human impact of the diminution of a fishery.
Regardless, we rarely eat fish here, with just an occasional visit to the fish ‘n chips joint down the street. As their chips are quite average at best, we have to be in the mood for the battered, deep-fried fish in order to go. I’m fortunate in that I generally don’t like fish at all, so I’m not tempted to indulge; my Arts Editor likes the occasional bit of salmon. Oh, and there’s that dratted fish oil pill that, upon digestion, issues minty-fresh burps. Repulsive.
