Applying Fisher Knowledge and Scientific Data to Understand Species Importance in Chilika Lagoon, India

Abstract

Direct monitoring of fish biodiversity can be challenging because of financial and logistical constraints. Conservation biologists have designated “surrogates”, which are a small number of species that represent the health of other species and/or overall environmental conditions. One type of surrogate, a keystone species, is a species whose impact is disproportionate relative to its abundance; the absence of which would change the dynamics of an ecological or a human community. This thesis advances a novel approach for identifying important fish species in Chilika Lagoon, India, by engaging with keystone literature as a starting point. To achieve this, four specific objectives guide this research: to 1) examine the strengths, drawbacks, and gaps associated with both ecological and cultural approaches to measuring keystone species status, 2) compare vernacular naming conventions for locally important fish across three ecologically and geographically disparate villages within Chilika Lagoon, India, 3) to identify the most important fish within each of the three Chilika Lagoon villages, and 4) to further investigate the social and ecological dimensions that guide fish importance. To achieve these objectives, I applied a mixed-methods approach, with an emphasis on community-based approaches.

First, a systematic scoping review was applied to examine the literature on keystone within the fish and fisheries context between 2014 and 2023. Key findings from this chapter highlight that many studies use the term “keystone” without formally testing to see if it is a keystone. Second, this review underscores the importance of ecosystem dynamic modelling through the program Ecopath with EcoSim in designating keystone species within an ecological context. Lastly, findings from this review point to an over-emphasis on ecological dimensions and an under-emphasis on cultural-social dimensions of the keystone concept. A recommendation from this chapter was to incorporate local knowledge of fisher folk when designating keystone species status.

To better contextualize fisher knowledge with respect to individual species, there is a need to link vernacular and scientific fish naming, so that results can be interpreted between formal as well as traditional/customary resource management systems. To achieve this, photos of 56 locally important fishes were shown to fishers (n = 108) across three villages by applying an age-gender-village approach wherein equal fishers were selected within each of age and gender groupings for each village. Key findings from this chapter highlighted that most species had multiple vernacular names, with many of these names being the result of phonetic differences. Secondly, no notable age or gender differences was apparent in the study sites in how people name fish. Lastly, village differences were apparent in how fish are named across all three communities. This research created a path forward for grouping locally important fish species by their vernacular names. Subsequently, a community-based approach was undertaken to designate important species in Chilika Lagoon, and to identify the rationale guiding perceptions of their importance. To achieve this, household surveys (n = 90) were administered across the three villages by applying a gender-village approach. Key findings highlight that while many important species were village-specific, commercially lucrative fish were identified as consistent across all villages. Additionally, women tended to select cultural reasons for fish importance, while men tended to select ecological and economic reasons.

The results presented in these three chapters illustrate the importance of taking a multi-dimensional approach that considers both keystone theory and community-based perspectives for designating and conserving important fish species. Chapter two provides us with a comprehensive understanding of the term keystone as it relates to fisheries holds significance because over 700 papers were examined to understand the trends, gaps, and strengths associated with the keystone concept. The value fisher knowledge can bring to designate keystone species was emphasized, and fisher perspectives were placed at the forefront of Chapters 3 and 4. This dissertation also helps to create stronger linkages between scientific and vernacular names (Chapter 3). Properly documenting the linkages between vernacular and scientific naming of local fish is necessary before fisher knowledge can be interpreted and applied. The linkages also allow us to accurately reference animal and plant species despite the many names applied across different languages. This initiative was significant because it captured the link between scientific and local names of Chilika fish and served as the building block to provide important insights for data interpretation and analysis of Chapter 4. Third, this research resulted in a novel method for determining species significance within a community because I consider both village and gender, as well as the underlying rationale for fish importance put forward by fishers, instead of using the keystone indicators from academic literature that were mentioned in Chapter 2. Fourth, this dissertation considers the intracultural diversity within the fisher community, and the importance of gender and village in helping to shape perspectives. These findings are important for both research and policy because it emphasizes the heterogeneity of fisher perspectives, and that findings from one group cannot be extrapolated to another.