The collapse of some fisheries could be avoided through an early alert system. (Photo Credit: NOAA)
Alert system developed to predict fisheries collapse
Thursday, September 19, 2013, 03:20 (GMT + 9)
Minimal adjustments in harvesting practices could help detect threats from overfishing early enough to save fisheries and livelihoods, according to a new research made by the University of Minnesota’s College of Biological Sciences.
The research, which was published in the Early Edition of Proceedings of the National Academy of Sciences on 16 September, was conducted by Matt Burgess, graduate student in Ecology, Evolution and Behaviour (EEB) who relied on the advice given by Stephen Polasky (EEB and Applied Economics in the College of Food, Agricultural and Natural Resource Sciences) and David Tillman (EEB).
According to this research authors, overfishing threats and prospective extinction of multispecies fisheries can be detected decades before they happen.
Through the “Eventual Threat Index” (ETI), included in the study, the method uses minimal data to detect conditions that would cause a particular species to be overfished. The ETI determines that if the fate of any one species can be predicted, then the future of all species can also be predicted in a similar way because multispecies fisheries impact several species with the same effort.
There are a few pivotal managed or profitable species, easy to detect and whose long-term harvest rate makes them somewhat predictable due to their socio-economic importance.
"The data we collect includes estimates of the relative population sizes, catch rates and the growth rates of different fish populations," Burgess points out."
And he adds: "This index uses what we know about what tends to happen to economically important fish to predict the fate of other species caught along with them."
This method was tested on several billfish and Pacific tuna populations. Four of these species have already been threatened with overfishing. This situation could have been detected as early as the 1950s if the ETI would have been used. The results show this capture practices much earlier.
Burgess says the index is easy and inexpensive to use and hopes fisheries will adopt it soon.
"In many fisheries, managers could calculate this index tomorrow using the description in the paper and data they have already collected," he added.
The research is revolutionary because although it is based on marine fisheries, it could be applied to multispecies fisheries in large bodies of water such as rivers.
By Gabriela Raffaele