Monday, February 20, 2017

Fishers' stories: not lies but useful tools

Commonly in Brazil people say “It is a fishers’ story”, when they refer to someone who is telling something that possibly is not true or that has been overstated. Well, surprisingly the information revealed by fishers are increasingly become an issue of interest to fishery scientists, managers and policy makers. Fishers have been turned in good suppliers of reliable facts. Let me explain it!

The majority of small-scale fisheries in developing countries usually have no data available to assess the stock status of target populations. Consequentely, to fulfill this gap, fishers have been called to tell what they know about it. This fact was recently showed in a paper about the small-scale fishery developed in one of the main hydroelectric reservoir in Brazil: the Itaipu reservoir (Fig 1). 

Fig.1: the Itaipu reservoir 

This reservoir produces the 25% of energy consumed in Brazil and borders Brazil, Argentina and Paraguay (Fig 2). During this research, we looked for the most experienced fishers in Itaipu reservoir. They were all willing to tell us about what they have perceived regarding to the fishery they practiced and the species they harvested through the years, including before and during the fishery monitoring carried out by researches of Maringá University.

Fig.2: the Itaipu reservoir boundaries

Results were promising and astonishing: fishers described with accuracy changes in species composition of the catches; they showed good knowledge about the ecology of some species; and all fishers deeply understand how the impoundment affected local fish species.
As a matter of fact, listening to them was like to be reading a scientific paper about the topic! Fishers were able to recognized the role of the river impoundment as the driver of changes in species richness and composition, as well as in the yield of large migratory and high-priced species, similar to what has been discussed in the literature. It is worth to say, they are predominately illiterate and clearly do not had access to scientific information published!

As life is not a bed of roses, histories diverged from local data collected systematically when absolute values are involved, such as when fishers were asked to recall their largest catch. Fishers tend to exaggerate when recalling their largest catch in a day. Apparently this shows that lack of memory is not the same of lack of truthfulness. Even though, fishers of Itaiou reservoir were homogeneous in their reports, indicating that instead of individual opinions, they revealed knowledge resulting from their everyday observation and fishery experience. They were also able to acknowledge some causes of catches decreasing, pointing out factors directly related with management: lack of enforcement of fishing regulations, capture of juveniles due to small mesh size used, higher number of professional fishers and increased number of recreational fishers. This is a factual proof that fishers are aware of the role of management and of their own commitment to develop a sustainable fishery in the reservoir.

Our study was able to identify that information supplied by fishers was similar to the data recorded by a local monitoring program, but not for absolute values of large catches and largest fish caught. The findings reinforce that fishers have a high ability to retain long-term information on fisheries, as it has been previous found in other studies. Fishers can be a reliable source of information for detecting changes in catches over time, especially when large-scale habitat changes have occurred within the time scale of a fisher career. Fishers may be key partners to be considered by managers in information gathering for effective management. This is the new story to be told!

By Juliana Strieder Philippsen

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