[Unarticlede[UnarticledeThe Conversation écrit par
Marguerite Taiarui – Doctorante au Criobe, Centre de ressources
pour les rahui, UMR241 Secopol, École pratique des hautes études
(EPHE)]
Night has long fallen on the barrier reef of Mo’orea. I am in the water, lamp off, guided only by the silhouettes of two fishermen and an anthropologist colleague. We are here to observe a fishing technique that until now I only knew through stories, and which is often described as devastating: the get help.
Earlier in the day, fishermen spent several hours arranging nets, forming a heart and leading to a cage. At the precise location where they installed this device, they know that the fish will start moving and rush into it.
The signal is given. We light our lamps and wave them in the water. We advance in line, without really understanding what we are doing, until we distinguish, in the dim light, the silvery reflections of a cage full of tortoise (soldier fish). What strikes me is not so much the quantity of fish as the finesse of the maneuver: everything is based on an understanding of the lagoon that these fishermen received from their elders but also built through observation, experience and the sharpening of their practices.
This nocturnal expedition says a lot about reef-lagoon fishing in French Polynesia: a practice that is ancient, complex and demanding. Essential to the life of communities, it feeds families, supports a local economy and has a strong cultural dimension. However, fishermen, scientists and residents are now observing worrying changes: reduction in the abundance and sizes of certain fished species, degradation of habitats, proliferation of macroalgae. The causes are multiple: overfishing, population growth, urbanization, land pollution, global warming.
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What can be done to sustainably manage the resource in the face of these transformations? We would tend to turn to science to obtain figures, analyze them and then define rules. However, local knowledge is immense: the finesse of get helporchestrated in the dark of night by two experienced fishermen, reveals an understanding of the lagoon that no scientific instrument can replace.
Knowledge to combine to understand the lagoon
Understanding what is happening in Polynesian lagoons requires mobilizing several forms of knowledge. Science, on the one hand, provides powerful tools to study the biology of targeted species, measure certain trends and quantify the effect of environmental pressures. These benchmarks are essential for imagining coherent management rules: minimum catch sizes, fishing effort thresholds, spatial or temporal closures.
But these approaches generally rely on abundant, standardized data collected over long periods. In Polynesian lagoons, they are difficult to collect: the number of fishermen is unknown, catches are rarely declared, sales are often informal, techniques vary and several dozen species are targeted. Added to this is a simple constraint: scientists cannot be everywhere, all the time. Detailedly documenting each portion of the lagoon, for each fishing gear and each species would require considerable resources, even though environmental changes are occurring now. We have neither the time nor the possibility of going back in time to know how things evolved.
This is precisely where local knowledge becomes essential. Fishermen observe the lagoon every day, sometimes for decades. They detect signals, variations in abundance or behavior that scientific monitoring struggles to capture. Their detailed knowledge constitutes valuable material for understanding how the lagoon works. But this knowledge also has its limits: it is situated, fragmented, linked to specific practices. They are no longer always enough to anticipate the future in a context of rapid change.
Science and local knowledge each shed light on a facet of the lagoon, without ever offering a complete vision. It is the complementarity of these two knowledge systems, and not their opposition, which makes it possible to imagine solutions that are fairer, more robust and adapted to the field.
Rules to build together
The day after our nocturnal expedition, I dissected, under the attentive gaze of the two fishermen, some tortoise captured in the get helpas part of a study of biological traits. One of them slips to me: “You’ll see, they’re all mature. This species starts to reproduce early, around 12 centimeters. »
This moment, seemingly innocuous, nevertheless summarizes the heart of the work undertaken for several months in Tahiti and Mo’orea. Fishermen, managers and scientists chose six fish species to study, based on their concerns. Among the latter, the establishment of minimum catch sizes comes up regularly. Fishermen have been asking for this for a long time: they themselves see that some are taking fish that are too small and that the pressure is increasing. But how to set these sizes?
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It is March 2023. After four years of ban, the Tautira regulated fishing zone is preparing to reopen to fishing for two half-days. The management committee wishes to establish minimum catch sizes and is turning to scientists to advise them. On the basis of studies carried out elsewhere in the Pacific, the recommendations fall: 18 cm for tortoise and 25 cm for ume tarei (nasons).
The fishermen immediately contest: “we never see individuals of these sizes”. After discussion, the size of tortoise is lowered to 15 cm but that of ume tarei is maintained.
The results of the opening confirm the complexity of the exercise. Of 1,490 tortoise captured, only 7% measured less than 18 cm. Conversely, less than twenty ume tarei could be fished and 69% were below 25 cm. “Imported” biology did not reflect local reality, while fishermen’s intuition abouttortoise also did not reflect the actual sizes of this species underwater.
These two examples clearly show that neither fishermen nor scientists alone have the complete solution. The first bring their continuous observation of the field; the latter essential biological markers. The question is not about being right, but about learning to understand each other in order to develop realistic, legitimate and applicable rules together.
Management based on respect and mutual listening
Fishermen are often presented as primarily responsible for the decline of stocks. However, those who are so easily accused are also those who feed the population.
Their detailed knowledge of the environment, built over the seasons and experience, is not opposed to science: it complements it where data is lacking or arrives too late. Science, for its part, provides essential benchmarks for understanding the biology of species and anticipating the effects of ongoing changes.
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Recognizing this knowledge equally means demonstrating empathy and intelligence: accepting that everyone sees a part of the lagoon, according to their history and their tools. It is by comparing these perspectives, rather than by hierarchizing them, that lasting, legitimate and truly applicable solutions can emerge.
