Seafood prices reveal impacts of a major ecological disturbance / by Francisco Blaha

While the bulk of my interest is in Oceanic fisheries, I’m always happy to learn novel approaches to the general fisheries conondrum. Obviously the traditional approaches have a mixed record at best, since we keep having some of the same problems for years, yet to be fair, that has to do more with our behaviour than to the methods we use to prove that we keep doing the wrong thing.

A recent paper I read, researched causal inference for coupled human-natural systems. Although establishing causality with observational data is always challenging, feedbacks across the human and natural systems amplify these challenges and explain why linking hypoxia to fishery losses has been elusive. They offer an alternative approach using a market counterfactual that is immune to contamination from feedbacks in the coupled system. Natural resource prices can thus be a means to assess the significance of an ecological disturbance.

If I had a few clones of my self and lot of money available, among the many thousands of other things I’ll love to do, one of them would be see if this approach (not with hypoxia obviouslly, but with another indicator) could be used in oceanic areas.

Below is the abstract of the paper:

Coastal hypoxia (dissolved oxygen ≤ 2 mg/L) is a growing problem worldwide that threatens marine ecosystem services, but little is known about economic effects on fisheries. Here, we provide evidence that hypoxia causes economic impacts on a major fishery. Ecological studies of hypoxia and marine fauna suggest multiple mechanisms through which hypoxia can skew a population’s size distribution toward smaller individuals.

These mechanisms produce sharp predictions about changes in seafood markets.

Hypoxia is hypothesized to decrease the quantity of large shrimp relative to small shrimp and increase the price of large shrimp relative to small shrimp. We test these hypotheses using time series of size-based prices. Naive quantity-based models using treatment/control comparisons in hypoxic and nonhypoxic areas produce null results, but we find strong evidence of the hypothesized effects in the relative prices: Hypoxia increases the relative price of large shrimp compared with small shrimp.

The effects of fuel prices provide supporting evidence. Empirical models of fishing effort and bioeconomic simulations explain why quantifying effects of hypoxia on fisheries using quantity data has been inconclusive. Specifically, spatial-dynamic feedbacks across the natural system (the fish stock) and human system (the mobile fishing fleet) confound “treated” and “control” areas.

Consequently, analyses of price data, which rely on a market counterfactual, are able to reveal effects of the ecological disturbance that are obscured in quantity data.