Indigenous and Traditional Knowledge Indicators for Ciguatera Fish Poisoning.
Here, we investigated whether local communities have a regional alert system to inform them of a potential ciguatera outbreak. Our study showed that local populations utilize ecological indicators or signs such as fauna, flora, atmosphere, and geological and astronomical events to indicate potential environmental risks that could negatively impact their health and well-being. We identified fourteen local indicators during the interviews with the communities. These indicators respond to changes within the natural environment that provide alerts to local communities on potential risks, such as CFPs (Supplementary Table 3). These indicators are based on our analysis (Fig. 2). Four indicators or ecological signs are the predominant indicators used by communities to monitor environmental changes related to the ciguatera outbreak; these indicators include extreme periods of heavy rainfall resulting in substantial runoff, a dense aggregation of jellyfish around the reef and near-shore areas, the proliferation of new corals within the reef area and ashes from volcanic eruptions.
During the interviews, the participants described how each ecological indicator is connected to ciguatera in fish, which resulted in fish becoming contaminated. These indicators are linked to changes in air and water temperature, water from certain types of trees, specific algal species within reef areas, or the behavior of certain fish. For instance, Interviewee A12 elaborated on the connection between Ciguatera and these ecological indicators, shedding light on how each one might influence the occurrence of the disease:
“During heavy rainfall, water from the Semecarpus vitiensis (Naulas tree) is washed down the streams, poisoning eels. When poisoned water reaches a reef, the reef fish are contaminated. Rainfall also washes waste and sediments down to the sea, contributing to environmental conditions for algae to grow. The fish will feed on the algae, and we eat the fish and get sick.”
Moreover, Interviewee A13 stated,
“Cordia dichotoma (clue tree) fruiting occurs with warmer air temperatures. The heavy appearance of jellyfish and new coral growing on the reef may signal a potential risk of toxic fish during the upcoming months.”
The Ambae people demonstrated a significant understanding of the island's phenology, which involved the study of the timing of recurring biological events and their relationships with seasonal and climatic changes. The interrelationships between living organisms and their environment's nonliving factors are known. They observe how flora and fauna on the island respond to natural changes such as temperature, rainfall, and sunlight and how these changes affect the growth, reproduction, and survival of these organisms. This knowledge is transmitted across generations and forms a crucial component of the daily lives of the people of Ambae Island. They also use this knowledge to make informed decisions regarding agriculture, fishing, and other activities that rely on the natural environment.
Validation and Dual Usage or Integration
We reviewed different policies and plans for Vanuatu and other regional and international organizations to identify potential suggestions for integrating the ITK with science for early warning systems. Nevertheless, no clear solutions exist for developing a framework that combines the two pieces of knowledge, although there are some mentions of the use of ITK with science. However, the ITK is mentioned for improving the information and understanding of environmental management challenges in a few policies and plans38–40. There is a need to bring scientists and local knowledge experts together to develop a framework of early warning that fits both science and local communities. For Vanuatu, this study emphasized that national and provincial governments must recognize the value of traditional knowledge and work with local communities to assess and identify best practices that can be integrated with scientific knowledge for the treatment of ciguatera fish poisoning outbreaks. The study identified the best policy strategies that could be used with ITK strategies to inform the development of an integrated early warning platform.
With technological advancements, the people of Ambae have access to scientific information on potential environmental risks (Fig. 3). The potential for integrating ITK indicators of ciguatera fish poisoning outbreaks with climate and fisheries early warning information from the Vanuatu Meteorology and Geo-Hazards Department (VMGD) and Department of Fisheries (DoF) allowed for the development of an integrated platform that is accessible, knowledgeable, acceptable, understandable, and valuable to both scientific and indigenous communities (Fig. 4). This approach will strengthen health authorities' ability to proactively provide health advice to the general public. Integrating ITK with science can provide more and better data to enhance local response and adaptation efforts during rapid environmental changes such as cigarette and fish poisoning outbreaks.
VMGD issues information on atmospheric phenomena such as extreme rainfall and tropical cyclone predictions, El Niño-Southern Occillation events, and ocean phenomena such as sea surface temperature, sea level forecasts, and coral bleaching outlooks. The DoF recommends actions for local people throughout Vanuatu to avoid lagoon and reef fishing if the coral bleaching alert is at its highest level, the chlorophyll concentration near the shore is above average, and algal blooms are observed in the area, especially in lagoons41. The ecological factors that trigger coral bleaching and high chlorophyll concentrations include nutrients and sediments carried by runoff during extreme rainfall42, which is similar to what was observed by local people after extreme rainfall in our study area.
Indigenous and traditional knowledge indicators mentioned atmospheric phenomena (periods of extreme rainfall, hot and warm weather, southeast winds), astronomical phenomena (new moon), flora (heavy flowering of seasonal fruit, heavy flowering of Calophyllum inophyllum (Nabagura tree), heavy fruiting of Cordia dichotoma (Clue tree), water from Semecarpus vitiensis (Walahi tree), heavy flowering of Erythrina variegata (Narara tree) and heavy presence of algae), and fauna (heavy presence of jellyfish, palolo worms and high number of new corals growing on the reefs and ocean phenomena (while bubbles are observed in the sea). While the Fisheries Climate Bulletin is regarded as a national advisory issued by two government agencies, the Vanuatu Meteorology & Geo-Hazards Department (VMGD) and the Department of Fisheries (DoF), this information needs to be downscaled to fit the different local communities around Vanuatu depending on the island's geography and situation. Indigenous and traditional knowledge indicators provided by local people can be used to bridge this information gap. Here, we design an integrated downscaling model, termed “The Gigila Framework” (Fig. 4), for ciguatera fish poisoning in Vanuatu based on the data from the people of Ambae and the data and information from the VMGD and DoF.
Table 1
Indigenous and Traditional Knowledge and Scientific Knowledge
Indigenous and Local Knowledge
|
Scientific Knowledge (Climate and Fisheries Sector)
|
|
Indicators
|
Indicator Behavior
|
Impact
|
Scientific Indicator
|
Outcome of Analysis
|
Impact
|
Coral Reef
|
New coral reefs growing within the reef area
|
Fish feed on the new coral and get contaminated with Ciguatera,
|
Chlorophyll
|
Chlorophyll Concentration Above Normal
|
Small fish accumulate, attracting large fish to the area
|
Jellyfish
|
High Presence of Jelly Fish around the reef area
|
Small fish feed on the dead jellyfish
|
Coral Bleaching
|
Alert Level 3
|
Fish feed on dead corals or algae growing on dead coral
|
Nabagura (Calophyllum inophyllum) Tree Flower
|
Heavy flowering of Nabagura Tree
|
Small fish feed on flowers falling into the water or washed down by run-off.
|
Tropical Cyclones
|
Increase run-off of nutrients and volcanic sediments
|
Fish feed on nutrients from land
|
Palolo Worm
|
The heavy presence of palolo worms
|
Fish feed on Palolo worms
|
Sea Surface Temperature
|
Coral Bleaching
|
Fish feed on dead coral or algae growing on dead coral
|
Extreme Heavy Rainfall
|
Surface and creek run-off carrying sediments down to the sea
|
Fish feed on nutrients from land
|
Heavy Rainfall
|
Surface Rub-off carrying Sediments down to the sea
|
Fish feed on nutrients from land
|
Algae
|
Algae growing on stones/dead coral
|
Fish feed on algae
|
Tropical Cyclones
|
Coral reefs destroyed
|
Fish feed on the algae growing on dead coral
|
New Moon
|
Appearance of the New Moon phase
|
Small fish eat more algae or plankton
|
Periods of heavy Rainfall
|
Run-off – nutrients and volcanic sediments end up in the ocean
|
Fish feed on nutrients from land
|
The Gigila Framework: Integrated Early Warning Platform for Ciguatera Fish Poisoning
We incorporated the "Gigila Framework" (Fig. 4) to develop an integrated early warning system. The term "Gigila" refers to the onset of risk used by the people of Ambae and Pentecost Island, indicating a high probability of occurrence of risk. This framework perfectly fits our recommendation, which combines local indicators and modern analysis (information bulletins) to create a downscale platform that is accessible and easily understandable for local communities. A standard operational procedure will guide the implementation of this model. By introducing the ITK into this concept, we aim to increase the confidence of local people and appreciate their contributions to the overall early warning system for ciguatera fish poisoning in Vanuatu.
An integrated communication platform has been developed to disseminate information about the risks associated with Ciguatera fish poisoning. The platform employs a dial concept that categorizes the risk level from low to high based on local and scientific analysis. However, to ensure its effectiveness, it is imperative to provide training to the provincial government, local communities, village health workers, tourism operators, and local fishing communities. This training aims to equip these stakeholders with the necessary knowledge and skills to effectively utilize the communication template and signboard dial.
The training aims to simplify scientific terms for local communities to enable them to make informed decisions concerning their health and well-being. This initiative is particularly relevant given the increasing trend of technology, which may lead to local people needing to be more accurate with scientific information from social media. Therefore, this platform aims to simplify scientific information and prevent such misinterpretation. An integrated communication platform is essential for local communities and the general public to understand the risks of Ciguatera fish poisoning. By providing the necessary training, we can ensure that the platform is effectively utilized and that the scientific information is simplified for easy comprehension by the local communities.
Community and Governmental Perspectives
The people of Ambae have acquired a significant understanding of their ecosystems through extensive personal observation and interaction, enabling them to adapt to environmental changes that shape their beliefs and practices. People often attribute issues to the anomalous behavior of plants or animals, a belief that is deeply ingrained in their beliefs and experiences. The knowledge of ciguatera, a type of fish poisoning, and its environmental impact has been transmitted through generations, and most interviewees have firsthand experience of ciguatera fish poisoning after consuming reef or offshore fish.
The study participants reported changes in the marine environment linked to increased cases of ciguatera contamination. According to the indigenous knowledge disseminated by community elders, certain fish have always been poisonous and can be easily distinguished. However, residents have recently observed that most fish, previously considered nontoxic, are now believed to be poisonous or toxic to ciguatera. This emerging trend is a cause for concern, as stated by Interviewee A5.
“There is an enormous change - fish that have not been poisoned before, now they are contaminated or poisoned” (A5)
while Interviewee A12 stressed that
“Changes in the environment, especially on the reef - new reefs are growing, and a new variety of algae is growing, which has not been seen there before. Fish eat these algae, and when they get contaminated, we eat the fish and get sick”. (A12)
The communities believe that toxins in fish can be attributed to various environmental factors, such as volcanic sediments, surface water runoff from land, dead jellyfish, and the consumption of new coral reefs by reef fishes. This progression of toxins moves up the food chain, eventually reaching humans, who consume the fish.
The residents of the North Area Council of Ambae understand that the cause of fish poisoning in the area is more closely related to the heavy rainfall between 2020 and 2023 and the sediments deposited during the volcanic eruptions of 2017 and 2018. As Interviewee A17 explained, the factors that impact the food chain ultimately affect the people who consume the fish.
“After our return from Maewo Island in 2019 and 2020, we noticed many changes to the marine environment, especially the new coral growing with a lot of new algae growing on dead corals, which we have never seen before. Volcanic ash deposits killed these corals during the eruption of the volcanoes in 2017 and 2018. During the last two years, 2021/2022, there was much rain here, resulting in many volcanic sediments being washed down to the ocean through creek channels. Our area here has ten major creeks extending to the coast, which are active with surface water run-off during active rainfall events”.
The island boasts numerous creeks, most of which can be found in the northern and western parts of the island. These creeks are vital for transporting volcanic deposits that were washed down to the coast and eventually flowed into the ocean during heavy rainfall. Due to their location, creeks act as natural conduits, allowing volcanic deposits to be easily transported to the sea. Notably, these creeks are an essential part of the island's ecosystem because they provide habitats for various aquatic species, and their banks serve as a source of nutrients for the surrounding vegetation.
A significant proportion of Vanuatu's population, approximately 74%, reside in remote and rural villages43, which poses a challenge in accessing pertinent government services and information. This prediction becomes more cumbersome when there are rapid changes in the environment due to climate change or other natural hazards, such as volcanic eruptions. We interviewed thirty-seven individuals to evaluate the importance of the ITK and its role in local ecological monitoring of environmental changes. The study's respondents strongly emphasized the criticality of the ITK, given its accessibility and ease of application or use. It is a consistent tool rooted locally and traditionally in living on islands. It is the first source for obtaining information about environmental changes that could impact people's health and well-being. Local people rely on indigenous and traditional ecological knowledge to monitor environmental changes before making decisions.
Interviewee A34 explained the importance of the ITK:
“Local knowledge is locally available, helps manage resources from the land and marine ecosystem, and comes naturally from God to be used and applied by local people.”
Like interviewee A34, interviewee A15 stated,
“Local indicators are like first-hand information since they are locally available. It is a first-hand information source, as it is free and available all the time”.
The findings from fieldwork data analysis indicate that 92% of the participants considered ITK an indispensable source of information about environmental change. Other sources, including community discussions, radio, social media, and local university student reports, are also perceived as beneficial for accessing information on potential environmental risks. Notably, Interviewee A20 underscored the critical role of the ITK in monitoring the environment for probable ecological hazards:
“We lived on the islands for many years. Our relationships and interactions with nature allow us to tell when such events will happen. Every day before I go out to do my daily activities, I pray and thank God, who provides everything. Whenever I came across a sign that nature showed, I knew that this was from God, and I must inform my family to prepare. It is free from God for us to use to sustain our living and to be resilient to what nature will impose on us. Nature provides challenges when it sees fit and informs us of them to prepare us to face them.”
According to Interviewee A31,
“Indigenous and traditional indicators are like first-hand information since they are locally available and easy to apply. Almost all community members know or have some knowledge of ITK, how to do things, and how to maintain ancestral beliefs and practices.”