Modeling fisheries - an interview with Dr. Paul Suprenand

We finally got to the end of our sequence of interviews with the IMBER crew, closing it with a flourish. We had a quick chat with Dr. Paul Suprenand, an expert modeler working with the Ecopath family, who also integrates physiology and ecology to address challenges associated with environmental change, especially related to fisheries. Paul is currently a post-doctoral research fellow at MOTE, in Florida (USA).

FEME: What are the advantages and disadvantages of modelling nature?

Dr. Paul Suprenand. Source: IMBER

PAUL: Nature is a very complex system, it has so many wonderful things to it, but in the model you cannot always capture all these little differences and they could be very important. So, the advantage would be that you have a way to look at some of the most important factors that could influence ecosystems or the animals within the ecosystem. However, you may lose some of the complexity. What is neat about the model is that it is more readily understood; you can ask questions or formulate hypotheses that could actually have some meaningful results to direct further research, or to help guide policies or ways in which you look at the system. So, overall, I think it is a pretty powerful tool, you have many different ways that the models can actually maybe capture some of the complexity lost in the individual model.

FEME: What would be the next steps for the improvement of Ecopath with Ecosim (EwE) approach?

PAUL: I think one of the neediest things is actually coming out, and it is something I had wanted for a long time. In the Ecospace portion of the modelling framework, there is now a way that you can start updating each of the individual maps for environmental drivers or things that may drive those trophic dynamics or energy exchanges in the ecosystem. For instance, in the artic or in the Antarctic, when you have sea ice coming into the ecosystem that is a very important part of how animals respond, their distribution, or whatever may occur. Historically in the ecospace system, you would have a static map, and so you could not see some of these differences of the environment drivers, like sea ice, overtime. Now there is a way that you can actually integrate or upload this data like the sea ice, so that when it changes you can also see the animal or food web responses as a whole. That is pretty cool, it is getting more into the complexity of the real life.

FEME: What changes would you like to see in the scientific community?

PAUL: I think we all have a need in our individual sciences to do more collaboration. Things like this [ClimEco Summer School], those workshops, are wonderful; you cannot reproduce them over emails, phone calls and the kind of relations you have here. However, I also think that us as individuals in the science, we have probably a greater opportunity these days to communicate our sciences, whether in social media or meetings on public libraries engaging the community in which we are living. I think it takes more these days to spread the science and the validity of science, or the things you know that essentially might get lost when you have translations in the news, when they say one result of science and they could be completely wrong in their interpretation. As scientists, we have a kind of obligation to make sure that we are reaching our communities, our audience, or our colleagues or hopefully the people who will be making decisions or people that you are living with, side by side; I think that would be important.

By Carolina Tavares

Bringing technology to our side – the use of unmanned aerial vehicles to help marine conservation

Unthinkable technologies – or thinkable only in Hollywood – have been emerging rapidly in the last decades. One incredible example and recently spread are drones. Drones are unmanned aerial devices that make a noise similar to drones, the male bee. Drones were originally created as a strategic war artifact, but now they have all kinds of applications, formats, and sizes. Some are so tiny that fit in your hand (Fig 1). 

Fig. 1. You can fit a drone in your hand.
Source: http://www.webdechollos.com/

Drones are polemic objects because they were originally created for military purposes. The USA has surveyed and attacked Afghanistan and Iraq using drones. In fact drones have seem to become really famous during the chase of Bin Laden. Several people also argue that the use of drones can shape wars to worse by reducing people’s empathy due to the lack of human-human contact (beats us to try to imagine an empathic war….). The use of drones also faces some legislation issues in several parts of the world. A few countries have clear legislation regarding the use of drones, its maximum flight height, size and permitted areas; in most case drones are not allowed to fly near airports and populated areas.

The association of GPS, smaller and more accurate cameras, thermal infrared cameras, and other sensory devices to drones expanded their uses. Drones have been used in cinema, advertisement, agriculture, and sports. Their widespread use is associated to their cost-benefit, as drones are relatively cheap, depending on what you need, you can purchase one for less than U$ 2,000.

Fig. 2 Dugong identification in Australia. Source: Hodgson et al. 2013.

Apart from these more popular uses we are all familiar with, drones are also helping solve problems in the biological sciences, and the integration among marine conservation biologists, computer scientists, and engineers are providing a handful of new applications for drones. For example, aquatic organisms use to be difficult to study and require methods such as underwater visual censuses, direct sampling, and aerial surveys, which tend to be all expensive and logistically difficult. Surveys of marine megafauna, in many cases, are already done with planes or helicopters, which are not only really expensive, but also noisy, which can disturb the animals being studied and interfere with the results. This is where drones, as predicted, come in handy: they come at a fraction of the cost of a plane, sound bug-like, and fly at lower altitudes, therefore providing more accurate images.

In the complex Amazonian environment drones are being used to map the distribution of the Amazon River Dolphin over a large area. This work is just beginning, but it has already provided an impressive amount of information at a low cost. Along the Australian coast, drones have counted hundreds of Dugongs during only seven flights covering 1.3km² each (Fig 2). Green Turtles have been successfully located and identified, and, even more impressive, their mating behavior has been also described using drone images (Fig 3). And the list goes on: drones have been used to map seabed coverage and nursery areas for juvenile fish, to detect body condition in humpback whales during breeding events, to survey cetacean in Timor Leste and to study sharks and rays densities in reef systems. Those who study small organisms can also benefit from the use of drones: for example, they have provided centimeter-scale images of reefs.

The potential of drones seems endless. They have been used to empower human communities and aid conservation: with proper training, people can use small drones to monitor forest use by local communities under a community-based management system. They can also be easily applied to monitor fisheries. In Belize, for instance, the government has compromised to use drones to fight illegal fishing.

Fig. 3. Location of green turtles. Source: Bevan et al. 2015

Two main flight methods are usually used in biological surveys and conservation monitoring. The first one requires the pre-programming of a grid to be covered during a flight, which is usually done with fixed-wing drones. This is a more systematic approach and can be used to get abundance and distribution data of a given species. The second approach requires a ground pilot to maneuver the drone and choose specific locations, individual or small groups of animals or areas to monitor. In this free-flight method rotary-wing drones are used, because these are more flexible and can fly at even lower heights.

Just as some other new technologies developed along the last years, the challenge now is how to analyze an enormous volume of data that drones provided. Nevertheless, a new path has been set to give drones are much more positive use than what made them initially famous for. 

 By Júlia Tovar Verba

References

Anderson, K., & Gaston, K. J. (2013). Lightweight unmanned aerial vehicles will revolutionize spatial ecology. Frontiers in Ecology and the Environment, 11(3), 138-146.

Bevan, E., Wibbels, T., Navarro, E., Rosas, M., Najera, B., Sarti, L., ... & Burchfield, P. (2015). Using Unmanned Aerial Vehicle (UAVs) Technology for Locating, Identifying, and Monitoring Courtship and Mating Behavior in the Green Sea Turtle (Chelonia mydas). Herpetological Review, 47(1), 27-32.

Chabot, D., & Bird, D. M. (2015). Wildlife research and management methods in the 21st century: Where do unmanned aircraft fit in? 1. Journal of Unmanned Vehicle Systems, 3(4), 137-155.

Chirayath, V., & Earle, S. A. (2016). Drones that see through waves–preliminary results from airborne fluid lensing for centimetre‐scale aquatic conservation. Aquatic Conservation: Marine and Freshwater Ecosystems, 26(S2), 237-250.

Hodgson, A., Kelly, N., & Peel, D. (2013). Unmanned aerial vehicles (UAVs) for surveying marine fauna: a dugong case study. PloS one, 8(11), e79556.

Kiszka, J. J., Mourier, J., Gastrich, K., & Heithaus, M. R. (2016). Using unmanned aerial vehicles (UAVs) to investigate shark and ray densities in a shallow coral lagoon. Marine Ecology Progress Series, 560, 237-242.

Paneque-Gálvez, J., McCall, M. K., Napoletano, B. M., Wich, S. A., & Koh, L. P. (2014). Small drones for community-based forest monitoring: An assessment of their feasibility and potential in tropical areas. Forests, 5(6), 1481-1507.

A fragile sex in fisheries?

In coastal settlements in Brazil, we often see women at the edge of the mangrove swamp, harvesting clams and seaweed, or back in their villages weaving nets and benefiting fish, with children in tow. The activities performed by these women are unstable and discontinuous, which depend unconditionally on environmental conditions, and also on social factors, such as being pregnant or with very young children at home.
Women’s work is socially, economically, and ecologically relevant, but still invisible. We don´t know exactly what, how much, when and why they harvest. We don´t know how much of their product ends up in the market and if their market poses the same limitations faced by fishermen. We don´t know if their work is even more important to food security than male’s work and if it also contributes to the household economy when other activities fail. We, as a country, fail to recognize the overall role of artisanal fisheries in Brazil, but we manage to do a much poorer job when it comes to recognizing the role played by fisherwomen.
Apart from the characteristic informality of the sector, one of the difficulties in making these women visible is the fact that we don’t have a general definition of the meaning of "fishing". Common sense and also current legislation define fishing as the harvest of fish from the sea or freshwater using some sort of fishing gear (net, line and hook, trap, harpoon, etc.). Under such definition, women participation in fisheries is basically irrelevant.
Clam and crab harvesting, locally known as mariscagem, is one of the most emblematic example of invisibility in fisheries in Brazil. This activity is performed in mangroves and tidal flats and is particularly dominated by women, especially clam harvesting. There is no database that accounts for how many shellfish women collectors are scattered along the Brazilian coast, but there are certainly over tens of thousands. In most instances they are not even locally and socially recognized as fishers, which contribute to the lack of statistics on their total number.

Dona Vera fishing in Bahia. Photo by Laura Honda

However, according to the World Bank, women play an extremely important role within the fishing industry; their data suggest that 47% of the people engaged in fishing are actually women. Recently, a study published in the journal Coastal Management sought to quantify and characterize the contribution of women in fishing, based on five countries: Mexico, Peru, Senegal, South Africa and Vietnam. The authors had to dig into whatever source they could find, but their findings did corroborate the utmost importance of women for the fishing industry. In these five countries, 1% to 13% of the people directly engaged in the fishing activity are female. While on the one hand these figures seem to indicate a modest contribution of women to the sector, their representativeness in activities indirectly related to the fishing sector such as processing and commercialization can reach up to 90%, as observed in Senegal. In Peru, for example, women represent 77% of the total number of people engaged in activities indirectly associated with fishing. If expanded for the other countries, we would very likely find the same exact picture. For instance, in the Brazilian northeast, women are estimated to represent about 35% of the workforce in activities related to the fish and seafood trade.
Another problem that women face to be recognized is the fact that their work often ends up being confused with domestic work. In the case of small-scale fisheries, women's work usually involves processing and marketing the catches, whose production chain is almost 100% informal. Most of the work is done from home, while women perform regular house chores.
For being invisible, these women do not enter fishing records and statistics, do not participate in decision-making processes and many fail to receive social benefits associated to fishing and social recognition. Bringing fisherwomen to the forefront necessarily involves a more precise quantification and characterization of their role in the fishing value chain and the strengthening of their organizational mechanisms. Women, especially in the northeast of Brazil, have been trying to improve their participation, not only by claiming rights for themselves but also for their communities. These women have been fighting to achieve representation for all fishers, regardless of their gender, and also for their communities in political instances where decisions are made; they have been trying to promote the insertion of the fishing economy in new socio-environmental contexts; and to unveil themes related to democracy, rights and environmental dynamics. The future belongs to them, but it is our role as scientists and organized civil society to make their path more amenable. 

By Ana Helena Bevilacqua

References

[1] Bevilacqua, A.H.V. et al. 2017. Following the fish: the income distribution in a Small-Scale fishery. In press.

[2] Guy, A. 2016. Vital but invisible: how subsistence fisherwomen around the world feed their families. Topic: Save the Oceans Feed the World. Oceana International Blog, oceana.org, April 7.

[3] Harper, S.; Grubb, C.; Stiles, M.; Sumaila, U.R. 2017. Contributions by women to fisheries economies: Insights from five maritime countries. Coastal Management, 45(2): 1-16.

[4] Maneschy, M.C.; Siqueira, D.; Álvares, M.L.M. 2012. Pescadoras: subordinação de gênero e empoderamento. Rev. Estud. Fem. vol.20 no.3 Florianópolis Sept./Dec. 2012.

Managing a transboundary fishery in the Amazon: The ornamental silver arawana case.

The Amazon basin is home for the silver arawana (Osteoglossum bicirrhosum), a fish better known in the international aquarium business as the “dragon fish” due to its phenotypic characteristics that makes it resemble a Chinese dragon, which has turned it into a highly popular pet in Asian countries. In such countries, this fish is believed to bring good luck and prosperity. Although not famous for its good looks, it is still an interesting fish that presents parental care by the male.

Silver arawana (Osteoglossum bicirrhosum). Image from http://www.acuamanus.com.ar

At the tripoint where the borders of Colombia, Brazil and Peru meet in northwestern Amazonia, the ornamental fishing of the silver arawana is a highly important economic activity for many riverine communities of the three countries. However, the management policies vary greatly between countries to the point where what Brazil implements is exactly the opposite of what the others do. In Brazil its ornamental fishery is forbidden in order to protect its stocks, but the adults can be exploited by the commercial fishery for consumption. It is a large fish (up to 1 m) and widely appreciated in the Brazilian Amazon diet. In fact, the silver arawana is the third species (in biomass) landed in Tefé, a Brazilian town near (~600 km) the study sites, where its demand keeps growing. On the other hand, Colombia and Peru legally permits the silver arawana live exploitation at the fish larval stage (3-5 cm) for the aquarium trade millionaire business. These countries regulate the ornamental fishery by imposing closed seasons (Colombia also imposes a quota). It does not mean though that Colombia and Peru actually sit down to agree on dates and areas to be closed; they make their decisions without talking to each other. In common, however, we have that both countries chose to ignore the recommendations done by researchers on the best period to close the fishing in order to protect the reproductive period of the species. Instead, they established closed periods that satisfy the market stakeholders’ (middlemen and exporters) interest.  What is already bad gets worse when fishers and middlemen disrespect an already inappropriate closed season, which is easy to do under institutional weakness. 

In a region where countries boundaries are not more than an abstract concept for people and for the fish they depend upon, it is easy to imagine that larval fish are also illegally collected in Brazil. In 2014, for instance, around 17% of the fish gathered by one of the study sites in Colombia (the middle Putumayo-Iça river) came from Brazilian grounds. Brazilian farmers open lakes that are inside their properties to Colombian fishers for an average of USD 4,400. In return, a lake can yield up to 30,000 silver arawana larvae worth more than USD 13,300. Where poverty reigns, such easy profits are hard to pass. 

Of the total volume of fish caught in Colombia or Brazil, 17% were marketed by Peruvian (illegally) and 83% by Colombian middlemen to the export firms of each country respectively. We can all see that managing this fishery is a herculean task because of its high profitability and the fact that it is performed in the middle of a very isolated region. However, it would be helpful if countries could talk for once and agree on their best policies, ideally considering the results provided by research. Countries and their managers would do even better if they could also address the consumer markets, namely the United States, Asia and Europe. One recommendation would be to call for the importing countries and regions to demand that the exporting ones comply with national and international laws, regulations and advice on fishery sustainability. One way to do that would be do demand fish traceability, where we could know if the fish are being harvested with environmentally friendly methods and subjected to better post-capture practices  that decrease mortality rates. No obstacle should be used as an excuse to not move towards an integrative management approach, under shared monitoring programs, management and market goals. Perhaps, existent programs, such as the Amazon Cooperation Treaty of 1978, can be used as a kick start to get the ball rolling.  Who knows, maybe this fish will be the key to unlock a true dialogue about sustainability in South America. 

By Adriana Maldonado

References

Maldonado et al. 2017. Transboundary fisheries management in the Amazon: Assessing current policies for the management of the ornamental silver arawana (Osteoglossum bicirrhosum). Marine Policy 76: 192-199.

It's all about Bayes in data-poor fisheries modelling

It is widely recognized that marine resources, although renewable, are not endless and need to be properly managed if their contribution to the nutritional, economic and social well-being of a fast growing human population have to be sustained. In this sense, maintaining long-term marine fisheries sustainability entails not only socio-political significance, but also economic and ecological importance.

So far, most of the fish stock assessments* performed rely on methods proposed in the first half of the twentieth century. Although robust, these methods are clearly outdated and inflexible because they demand big data set and they do not take into account the interactions that exist between the biological, physical and anthropic components.

However, most of the ongoing fisheries research has to face the lack of regular data, making conventional stock assessment tools usually not applicable to data-poor situations. This is particularly a concern for developing countries, where fisheries tend to be poorly documented and inadequately managed due to limited funding for monitoring and data analyses. Still, in such countries fisheries play a major role in food security and well-being for the poor.

 One alternative that has been adopted to overcome this issue is to use more flexible models. Nevertheless, one might still wonder: could more flexible quantitative methods still perform well and be reliable under limited information? The answer to this crucial question is: Yes, it could! And indeed they do it very well!

A paper published very recently has used a set of different statistical approaches in order to extend the scope of data-poor fisheries. The study was carried out in Rio Grande do Norte state - a small coastal state on the Brazilian northeast - where the authors studied the endangered lane snapper (Lutjanus synagris) that is caught by the artisanal fleet (Fig. 1).

Figure 1: (A) Typical artisanal fleet that operates with bottom-set gillnets along Rio Grande do Norte state and (B) an example of an adult lane snapper (Photo of the fishing fleet: Marcelo Nóbrega; Photo of the lane snapper: Garcia Jr. et al., 2010)

   The new ingredient of this paper was based on the legacy left by the English Reverend Thomas Bayes (and also by Pierre S. Laplace, although this one is not properly recognized) (Fig. 2), and which has come to be known as Bayesian reasoning. Through Bayes theorem one might update her initial belief about something with new information, and thus get a new and improved belief. In essence everybody could consider herself a Bayesianist, as our updated knowledge is always initially shaped according to our initial beliefs. 

Figure 2: Thomas Bayes (left) and Pierre-Simon Laplace (right) (References: Wikipedia).

  Specifically, the authors of this paper addressed Bayesian reasoning into two important fisheries modelling issues, namely the estimation of mean size at which a species reaches first maturity (L50) and the prediction of a species’ spatial distribution. By knowing the L50 of a fish stock (or fish population) we can divide it into juveniles and adult individuals and therefore propose policies to restrict the fishing of juveniles, i.e., when a fish mean length is smaller than the estimated L50. Moreover, knowing the spatial distribution of juveniles and adults gives an overview of where each one occurs preferentially. This information helps subsidize management policies based on the use of the space by the fish, as it allows for instance the protection of specific fishing grounds,  where juveniles aggregate. 

     In this sense, by including Bayesian reasoning in these two issues, it was shown that it is a useful model for data-poor situations. This happened primarily because of the Bayesian properties, which permits that a researcher not only handles smaller datasets than usual, but also incorporates any available information to the data. The latter case is of particular interest, once it allows the results to adapt themselves automatically as we acquire more data. Thus, even if someone has a small dataset, she can either use the literature or use her own information to accumulate data and produce more reliable results.

  Last, but not least, by using Bayesian models the researchers were able to quantify the uncertainty of the predictions in a straightforward way.  In fisheries science, we do not control the data, we typically only observe it, and such observation is usually incomplete, which leads to several error sources (imperfect observations, inappopriate sampling procedures, model structure and parameter definition, etc.). This is where uncertainty emerges. Thus, if one desires to provide an accurate picture of the investigated phenomenon, it is of fundamental importance to account accurately for these multiple uncertainty sources in the models. Also, by quantifying the uncertainties someone has greater control of the quality of her results and, consequently, more freedom to make specific decisions upon the evaluated process.  For instance, in fisheries management, questions like ''what is the probability that the current catch levels of a given fishing resource remains sustainable'' or "what is the probability that area A has greater conservation potential than area B'' can only be answered under the Bayesian paradigm. Therefore, knowing that uncertainty is inherent to all scientific realms, its inclusion in the decision-making process is not only desirable, but essential.

By Marie-Christine Rufener

*a stock assessment is an evaluation of a given fish population. It can provide multiple information, such as the total biomass or the total number of individuals in that population, but it can also bring information on age estructure, fecundity, proportion of males and females, etc.

References
Garcia Jr., J.; Mendes, L. F.; Sampaio, C. L. S. & Lins, J. E. 2010. Biodiversidade marinha da Bacia Potiguar: ictiofauna. Rio de Janeiro, Série Livros 38, 195p.

Web references
https://upload.wikimedia.org/wikipedia/commons/thumb/9/91/Pierre-Simon-Laplace_(1749-1827).jpg/170px-Pierre-Simon-Laplace_(1749-1827).jpg accessed on March, 2017


https://upload.wikimedia.org/wikipedia/commons/d/d4/Thomas_Bayes.gif accessed on March, 2017

An interview with Dr. Ingrid van Putten

Photo: ResearchGate

Dr. Ingrid van Putten is a scientist working with the ecosystems modelling team at the CSIRO Oceans and Atmosphere, in Hobart, Australia. She is also a member of the IMBER Scientific Steering Committee and Human Dimensions Working Groups. Her research focuses on the social and economic behavior modelling of interaction with the biophysical marine environment and on understanding coupled social-ecological systems. Because complexity in the bio-physical sphere is mirrored in social and economic systems, she focuses on the tools that effectively model social and economic data and aims to find the optimum level of complexity for human behavior models. Ingrid has used network analysis to model lease quota trade systems and Bayesian models to investigate non-economic drivers in indigenous fisheries. She has also applied qualitative models to investigate the drivers of participation in marine sectors in the context of climate change. Some of her work is focused on improving the management of coupled social-ecological systems and ensure their long-term viability.

 

In the month we celebrate the international women's day, nothing better than listening to Dr. van Putten talking about not only socio-ecological marine systems, but also about the role of women in science. Enjoy it!

FEME: Can we reach sustainability in our socio-ecological marine systems?

Ingrid: I think so. I hope so. I think, for all of us and our children and their children, we need to be sustainable and if there is a need there is a way, and I think that we will have to change our behavior to make it sustainable. And when the need increases the system can either fall apart or it can stay together and I think it will remain together to make the future possible, but we will need to change.

FEME: How far will we need to go to realize we need this change?

Ingrid: I think we are realizing it very slowly, but I think that your generation is already realizing it a lot more. In the next 20 years we will all need to make the change, otherwise there won’t be much to change. But I think it’s possible because your generation is so smart, they are learning about the vulnerability of the planet much earlier than previous generations did, so I think there is hope in the next generation.

FEME: I agree, but I’m afraid that our generation is waiting for some sort of a magical solution or technology that will deal with all pollution, rebuild the oceans and things like that.

Ingrid: I think technological solutions are important to some degree, but they won’t solve everything. I can see where you are coming from, it’s difficult, right? But I think if we don’t have hope we might as well give up. Even if sometimes we believe it is so hopeless, we need to change the way we speak about it, because you know, when you are sad about something you can talk yourself into being happy again. I think it is the same about the way we think about the future, if we always talk about it being broken and having no solution, then there is no solution. We need to start talking about the solutions, and technology is really important. I think that if we want to stop using fossil fuels, we can, we just need to find technologies and alternatives there are not destructive. But if we always say there are no alternatives then there are no alternatives. We need to be positive towards the future and believe that things are possible and then make them possible. That’s your responsibility.  

ClimEco5/IMBER - Natal, Brazil

FEME: What motivated you to switch from more traditional economics to a more environmental approach?

Ingrid: The traditional economics is really interesting, but I felt that I needed to broaden my view to be more about the behavior of groups of people that wasn’t so restrictive. I was in environmental economics, and then I started off switching to agriculture economics and then I went into environmental economics and then I went into behavioral economics. I felt that I wanted to better understand why we make irrational decisions about things, like climate change, and why we are making all these strange decisions. Economics can explain a lot of that but so can socio-psychology. I felt that to understand how we deal with climate change and overharvesting, and exploitation of the environment, we needed to understand better that there is a lot in that that is psychological. The solutions are actually a lot about socio-psychology. If we believe that we can do something as a group, then we can make it happen. We need both [economics and socio-psychology], but I think there has been less attention paid to the other side, to the social side for the solution.

FEME: Which changes would you like to see in our scientific community?

Ingrid: The changes I’d like to see are already happening to some degree, and that it is to try to understand each other’s discipline better, to expose people in the natural sciences to principles from the social sciences and to use each other’s methods and tools. We don’t need to understand everything about the other sciences, just a little bit can help. It is just so we don’t stay with blinkers in our eyes, we open up a little bit and become more accepting of people’s views, because some views are formed just by being in one discipline. If you open your eyes to other disciplines you may have a new perspective. Not that people have to became generalists, some people are good generalists, some people are good specialists and we need both of those as well. I think it is the opening up of your mind to other things. And I also care about women being more involved in science and decision making, making it more possible for young women who want to have children and be out of the work for a little while to come back without starting over from the bottom. If women were more able to be continuously involved in decision power, I think the world might be a better place. If we can find some equality between men and women in all fields, if we can be more equal in the way we work, the way we understand each other this is also a big step for the world.  If I have to pick two things then it would be those things for science [exposing people to different science approaches] and making it possible to accommodate young women’s needs in science better, so when you do a post doc you can do it part-time if you decide to have a baby, because that is the time of your life when you might have one. I think these are important issues.

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

Philippsen, J. S., Minte-Vera, C. V., Okada, E. K., Carvalho, A. R., & Angelini, R. (2016). Fishers’ and scientific histories: an example of consensus from an inland fishery. Marine and Freshwater Research.