From Ethnobiology to Ecotoxicology: Fishers’ Knowledge on Trophic Levels as Indicator of Bioaccumulation in Tropical Marine and Freshwater Fishes

Ethnobotanical contributions to global fishing communities: a review

BACKGROUND

Ethnobotanical knowledge about the role of plants in fisheries provides valuable ecological information vital for sustainable management of local resources; however, it is diluted and understudied globally. This literature review aims to map the knowledge of plant use within traditional fishing communities.

METHODS

Through the PRISMA method, we identified and selected 34 articles reporting the use of plants in fisheries, and including 344 taxa of plants and algae. Uses of plants and algae were grouped into different categories.

RESULTS

In the novel categorization of fishery-related uses we proposed, the most mentioned were for fishing and building/repair of fishing artifacts and habitat-related uses, while the records of plants related to fiber uses, providing aid in fishing management and species causing problems, were among the least mentioned. Semi-structured interview is most commonly used with local resource users, especially fishery experts, in exploring perceptions on plant use within traditional fishing communities. Diversity was high in all the recorded families, but most were reported locally.

CONCLUSION

Ethnobotanical studies with fishers are not common in the documented literature but they provide a large number of use reports. On the basis this review, in most of the world, the information is of a casual and sporadic nature. Fishers can provide information on aquatic plants and algae that create problems and aid in fishing management, which are crucial in understanding the ecosystem of a region experiencing environmental challenges. This knowledge is greatly understudied globally and undergoing a rapid decline, as highlighted in several of the reviewed articles. Thus, further systematic research on fishery-related uses of plants by fisherfolk is needed considering its potential contribution to the sustainable management of fishery resources.

Perfluoroalkyl substances in freshwater and marine fish from northern Vietnam: Accumulation levels, profiles, and implications for human consumption

The accumulation profiles of nine perfluoroalkyl substances (PFASs) were determined in 95 muscle samples of seven freshwater (n = 65) and seven marine (n = 30) fish species collected in Northern Vietnam. In both groups of fish, perfluorooctane sulfonic acid (PFOS) was the most prevalent component, accounting for roughly 29 % of total PFASs. The total PFASs in freshwater fish species ranged from 0.08 to 8.06 ng/g wet weight (w.w), with the highest concentration found in topmouth culter (7.01 ± 1.23 ng/g w.w). In marine fish, the highest mean concentration of PFASs was detected in Asian sea bass (2.75 ± 0.54 ng/g, w.w). Estimation on the human dietary intake of PFASs from fish consumption resulted in hazard ratios (HR) ranging from 0.019 to 0.238 for freshwater fish and from 0.016 to 0.074 for marine fish, indicating low exposure risks associated with PFASs.

Alternative Conservation Paradigms and Ecological Knowledge of Small-Scale Artisanal Fishers in a Changing Marine Scenario in Argentina

We studied conservation paradigms of small-scale artisanal fishers and other actors involved in the conservation of the Bahía Blanca Estuary (BBE)-a Southwestern Atlantic estuary under anthropogenic pressures (conservationists, NGOs, individuals in the private sector and the port consortium). We focused on the relationship between fishers and non-human entities (e.g., animals, tides, lunar cycles, etc.) from alternative conservation paradigms according to Pálsson's schema (orientalism, paternalism, communalism). We also explored the ecological knowledge of fisher communities to identify possible conservation strategies. Using an ethnographic approach, we identified communalism as the dominant paradigm within the fisher communities as opposed to the paternalistic and orientalist approaches of conservationists and industry employees in the BBE. Fishers demonstrated a broad knowledge on the effects of climate change on fish stocks and pollution on ocean environments and biota, which gillnets avoid catching juveniles and threatened species, and landscape changes over the long-term period, among others areas that could be useful for conservation of these changing coastal ecosystems. We conclude that understanding local perspectives and practices is essential for a democratic exchange among different bodies of knowledge to conserve marine ecosystems.

Which fish is this? Fishers know more than 100 fish species in megadiverse tropical rivers

Ethnobiological studies on folk, common, or popular names that fishers use to identify fish can help improve fisheries monitoring and collaborations between fishers and researchers. This study investigates fishers’ knowledge (recognition, naming, and habitat use) on 115 and 119 fish species, respectively, in the Negro and Tapajos Rivers, two megadiverse rivers in the Brazilian Amazon, and investigates the relationship between such knowledge and fish importance to fisheries, fish abundance, and fish size. We also compared fishers’ perceptions on fisheries and fish abundance with literature data on fish harvests and fish sampling. We interviewed 16 fishers in 16 communities (one fisher per community, 8 communities along each river). These fishers recognized an average of 91 ± 10.4 species in the Negro River and 115 ± 7.2 species in the Tapajos River, but all fishers recognized 114 species in Negro and all species in Tapajos. The fishers’ knowledge of fish species was positively related to fishers’ perceptions on fish abundance, size, and importance to fisheries in the Negro, but only positively related to fish size in the Tapajos. Our results highlight the usefulness of fishers’ knowledge to providing data on use and cultural relevance of fish species in high diversity aquatic ecosystems.

Known but not called by name: recreational fishers' ecological knowledge of freshwater plants in Hungary

BACKGROUND

Documenting local ecological knowledge (LEK) has recently become a topic of considerable interest. LEK can contribute to various areas of ecology, including habitat management and conservation biology. It has been recently revealed that recreational fishers' ecological knowledge (FEK) can also provide valuable information about different organisms and habitats, while recreational fishers' ecological knowledge is understudied in many aspects and regions of the world.

METHODS

We aimed to record Hungarian recreational FEK on plant species related to freshwater habitats. Our research was conducted in three regularly fished water bodies in Hungary, namely Lake Velence, Keleti Main Canal, and Lake Látóképi, where a total of 72 interviews were conducted with recreational anglers. During interviews, 24 plant species occurring at freshwater habitats with common or sporadic distribution were shown to anglers as single species or in congeneric pairs. Miscellaneous plant-related knowledge of anglers was also collected.

RESULTS

Anglers identified a total of 16 plant species. They used 45 botanical or folk names. An angler knew the name of 4.6 plants on average and recognized 7.4 other species without naming it. According to our detailed analysis, anglers were able to name or at least recognize those plant species which are somehow related to fishing activities, are salient, and/or common. Moreover, anglers at Lake Velence recognized less plant species; however, they also had less years of fishing experience compared to anglers of the other two locations.

CONCLUSION

We found that recreational FEK exists even in the case of freshwater plants which are not the main focus of anglers. It is highly presumable that recreational fishers would be able to provide reliable ecologically related data for scientific research establishing future citizen science projects of nature conservation.

‘Taking Fishers’ Knowledge to the Lab’: An Interdisciplinary Approach to Understand Fish Trophic Relationships in the Brazilian Amazon

Trophic levels can be applied to describe the ecological role of organisms in food webs and assess changes in ecosystems. Stable isotopes analysis can assist in the understanding of trophic interactions and use of food resources by aquatic organisms. The local ecological knowledge (LEK) of fishers can be an alternative to advance understanding about fish trophic interactions and to construct aquatic food webs, especially in regions lacking research capacity. The objectives of this study are: to calculate the trophic levels of six fish species important to fishing by combining data from stable isotopes analysis and fishers’ LEK in two clear water rivers (Tapajós and Tocantins) in the Brazilian Amazon; to compare the trophic levels of these fish between the two methods (stable isotopes analysis and LEK) and the two rivers; and to develop diagrams representing the trophic webs of the main fish prey and predators based on fisher’s LEK. The fish species studied were Pescada (Plagioscion squamosissimus), Tucunaré (Cichla pinima), Piranha (Serrasalmus rhombeus), Aracu (Leporinus fasciatus), Charuto (Hemiodus unimaculatus), and Jaraqui (Semaprochilodus spp.). A total of 98 interviews and 63 samples for stable isotopes analysis were carried out in both rivers. The average fish trophic levels did not differ between the stable isotopes analysis and the LEK in the Tapajós, nor in the Tocantins Rivers. The overall trophic level of the studied fish species obtained through the LEK did not differ from data obtained through the stable isotopes analysis in both rivers, except for the Aracu in the Tapajós River. The main food items consumed by the fish according to fishers’ LEK did agree with fish diets as described in the biological literature. Fishers provided useful information on fish predators and feeding habits of endangered species, such as river dolphin and river otter. Collaboration with fishers through LEK studies can be a viable approach to produce reliable data on fish trophic ecology to improve fisheries management and species conservation in tropical freshwater environments and other regions with data limitations.

A "new normality" for small-scale artisanal Fishers? The case of unregulated fisheries during the COVID-19 pandemic in the Bahía Blanca estuary (SW Atlantic Ocean)

The current COVID-19 pandemic is causing health and economic crises worldwide, but consequences are worse for those emerging countries with poor sanitary conditions struggling against economic recessions. Small-scale artisanal fishers (SSAF) should be considered among the "essential workers" since they provide food services; however, the COVID-19 might have altered the normal livelihood and reduced people economic incomes in an already marginalized sector. This situation highlights the fishers' vulnerability, derived from changes in fish stocks caused by climate change, pollution, overharvesting, and informal work (illegal, unreported and unregulated fishing). Therefore, the so-called "new normality" raises big questions about the management of coastal areas and fisheries in developing countries. As a study case, we proposed exploring SSAF from an Argentinian estuary, the Bahía Blanca estuary (SW Atlantic Ocean). Most of them are unregulated after a reconversion program carried out by the local government in 2012. After reviewing the current COVID-19 legislation for coastal fisheries and having virtual encounters with SSAF, we observed they are struggling against the economic crisis caused by the pandemic. According to our observations, imperative measures must be taken to prevent fisheries collapse in the area. In this work, we present a reference point for the post-pandemic management of fisheries that could be considered for emerging public policies.

Invisible contaminants and food security in former coal mining areas of Santa Catarina, Southern Brazil

BACKGROUND

Mining activities have environmental impacts due to sediment movement and contamination of areas and may also pose risks to people's food security. In Brazil, the majority of coal mining activities are in the south, in the Santa Catarina carboniferous region. In this region, previously mined areas contaminated with heavy metals frequently occur nearby inhabited zones. Mining is part of the daily lives of local communities, and its environmental impacts are visible in the landscape; however, plants with medicinal and food use from these areas can be still consumed. Heavy metals are contaminants that do not have odor, color, or taste, and are therefore difficult to detect. We aimed to verify whether people use plants from contaminated mine areas, and understand which factors can influence the use of these resources, even from areas visibly impacted.

METHODS

We conducted 195 semi-structured interviews with residents from 14 areas nearby abandoned mines in the main municipalities of the Santa Catarina carboniferous region. We asked each interviewee about the length of time they lived in the region, their perception of the quality of the environment, and what plant species were used and for what purpose. We constructed generalized multivariate linear models to verify which variables can affect the group of species mentioned and generalized linear models to verify which variables can affect the total number of citations. We estimated the frequency of citing species collected using the Smith index.

RESULTS

From all interviewees, 127 (65%) reported collecting plants for medicinal and food use, directly from contaminated mine areas. Long-term residents, as well as those who noticed more environmental changes (positive and negative), cited more plants used and had more detailed knowledge of plant use in their communities. When asked if they were aware of the possible contamination of mined areas, 85% said they knew about it. However, only 10% associated negative health effects with the use of plant species collected in contaminated mined areas.

CONCLUSIONS

Our study demonstrates that people living nearby contaminated areas use and consume locally sourced plants, e.g., people know little about the danger of this contamination in their food and the risk of these contaminants to their health. These results also reveal a lack of information about contamination, as well as a lack of actions that include local communities in contaminated area restoration strategies. This situation poses a risk to the food security of the people living nearby former coal mining areas.

Participatory Research with Fishers to Improve Knowledge on Small-Scale Fisheries in Tropical Rivers

Freshwater small-scale fisheries sustain millions of livelihoods worldwide, but a lack of monitoring makes it difficult to check the sustainability of these fisheries. We aim to compare and describe participatory research methods used in studies with fishers in the Tapajos River, a poorly known tropical river in the Brazilian Amazon. We address three interview approaches, two ways to do fisheries monitoring and two approaches for georeferenced mapping based on fishers’ knowledge, which can provide data about at least 16 topics related to fisheries. We highlight major advantages and shortcomings of these methods and illustrate their potential with examples of results on fisheries and fish biology of Peacock bass (Cichla spp. tucunaré in Brazil), an important commercial fish in the Brazilian Amazon. The interviews, participatory monitoring and mapping revealed which fish are more valued by local communities, how fish abundance and sizes varied over time, when fish are more often caught and show reproductive activity, and which sites or habitats fish need to reproduce. In addition to providing useful data from many sites in a cost-effective way, participatory methods can bring the additional benefit of including local stakeholders in the monitoring, management, and research activities.

Fishers and groupers (Epinephelus marginatus and E. morio) in the coast of Brazil: integrating information for conservation

BACKGROUND

Groupers are a vulnerable but economically important group of fish, especially for small-scale fisheries. We investigated catches and local ecological knowledge (LEK) of diet, habitat, and past fishing experiences.

METHODS

Landings, prices, interviews, and restaurants demand for two species, Epinephelus marginatus (dusky grouper) and Epinephelus morio (red grouper), were registered.

RESULTS

We visited 74 markets and 79 sites on the coast of Brazil in 2017-2018, and we interviewed 71 fishers: Bahia (NE), Rio de Janeiro and São Paulo (SE), and Santa Catarina (S). The landings sampled of dusky grouper (2016-2017) in Rio de Janeiro were: n = 222, size 38-109 cm, weight 1-24 kg, average 3.84 kg; in São Paulo, São Sebastião were: n = 47, size 39-106 cm, weight 2-8 kg, average of 2.77 kg; and at Santos: n = 80, 26-120 cm, weight 0.36-15 kg, average 2.72 kg. Red grouper was observed in markets in the northeastern Brazil. We did not observe Epinephelus marginatus from Bahia northward; a maximum size of 200 cm was reported south of the Bahia, besides Rio de Janeiro and São Paulo coasts, 20 years ago (or longer) by 12 fishers. Local knowledge of fishers was important for grouper data of habitat and diet; the reproduction period was identified by fishers as September to March.

CONCLUSIONS

Groupers can be considered as a cultural and ecological keystone species. We suggest protective measures: 1) fishing zoning, 2) islands (MPAs) with the surveillance of fishers, 3) late Spring and early Summer as key periods for management (grouper reproduction), 4) studies on grouper larvae, 5) mapping of fishing spots, 6) studies on local knowledge. Collaboration with small-scale fishers and local knowledge could contribute to low-conflict management measures. In that regard, integrative models of management from Latin America, by using local knowledge and citizen science, could produce successful grouper management for Brazilian data-poor fisheries, a contrasting reality to the Mediterranean areas. Finally, the distribution of E. marginatus in Brazil leave us with questions: a) Have dusky groupers disappeared from Bahia because of a decline in the population? b) Was it uncommon in Northeast Brazil? c) Did changes in water temperatures forced a movement southward?

Freshwater neotropical oligochaetes as native test species for the toxicity evaluation of cadmium, mercury and their mixtures

The toxicity of metals, whether isolated or in mixtures, involves changes in biochemical processes as well as in cell membranes, which may lead to deleterious short- and long-term effects on the affected organisms. Among metals, cadmium and mercury stand out due to their abundance in nature, frequent use for industrial activities and biological accumulation, with high levels of residence in trophic chains. Benthic communities are particularly prone to metal pollution since metals usually accumulate in sediments. The aim of this study was to evaluate the acute toxicity of mercury and cadmium, single and in mixture, to two native species of epibenthic oligochaetes: Allonais inaequalis and Dero furcatus. In order to assess the potential of these species as bioindicators, we compared their sensitivity with those of other internationally used species by applying the species sensitivity distribution approach. The 96h-LC₅₀ of cadmium chloride was 627 and 364 μg L^-1 for A. inaequalis and D. furcatus, respectively, evidencing that the latter species is almost twice as sensitive to this metal than A. inaequalis. For mercury chloride, the 96h-LC₅₀ was 129 μg L^-1 for A. inaequalis and 92 μg L^-1 for D. furcatus. The sensitivities of these oligochaetes were superior or similar to that of other frequently used oligochaete test species such as Tubifex tubifex and Lumbriculus variegatus. The metal mixtures had synergism in general (D. furcatus) or at high doses only (A. inaequalis), implying a potentiation of their toxic effects when both metals co-occur in the environment. By comparing the derived toxicity values with concentrations of cadmium and mercury measured in the field, it can be concluded that aquatic organisms are likely to be at risk when exposed to the environmental relevant concentrations of cadmium and mercury here tested, especially when they are both present.