Mahseer Trust habitat advisor, Dr Mark Everard ponders about how we assign value to mahseer.
What is a mahseer worth? You can buy a dead mahseer in a fish market where they are harvested in southern Asia, or a live one, sold by an aquaculture or aquarist supplier but that narrow framing of financial value is just a tiny fraction of the true worth of these and other fishes.
Expressing the values of mahseer
A paper titled "Assessing the societal benefits of mahseer (Tor spp.) fishes and habitats to strengthen the basis for their conservation" has recently been published in the prestigious international science journal Aquatic Conservation (click for link).
This new paper recognises that mahseer fishes have long been valued as a food source and also serve a range of other societal roles. However, the benefits that mahseer provide to people go beyond their direct exploitation and cultural associations. They also include their importance as indicators of the functioning of the healthy ecosystems of which they are part and upon which they depend. These broader ecosystem benefits to people constitute important indirect co-benefits from the presence or conservation of mahseer. The research recognises all of these diverse and qualitatively differing benefits through the lens of 'ecosystem services': the multiple range of benefits that people derive from ecosystems, ranging from direct exploitation, cultural enrichment and the maintenance and regulation of ecosystem health.
Recognising qualitatively different values of mahseer
This wider framing of the multiple, and qualitatively diverse, values of mahseer is important for recognition of the importance of the conservation of these iconic fishes. The meanings and values connected with mahseer populations range from the spiritual to the consumptive, and the wider functioning of freshwater ecosystems from which so many human benefits flow. As the rivers that support mahseer and other fishes integrate pressures from across catchment landscapes, mahseer as apex predators and 'umbrella species' - reflecting the health of the aquatic habitats that support them and their associated biodiversity - act as barometers of the vitality of wider landscapes and waterscapes and the uses to which they are put, with additional significant cultural values recognised by the term 'iconic species'.
Assessment of ecosystem services used in this research was based on the RAWES (Rapid Assessment of Wetland Ecosystem Services) approach, adopted as an international standard by the Ramsar Commission in 2018. Literature review underpinning the paper's analyses found that wild mahseer populations play direct roles in 11 of the 36 assessed ecosystem services, ranging from their use as food, in aquaculture, as spiritual symbols, and in recreation, including angling and ecotourism.
However, the habitats essential to support mahseer contribute significantly to a further 18 ecosystems services, ranging from disease regulation to nutrient cycling, seed dispersal, supply of fresh water, and research and education. The direct and indirect contributions of mahseer to the provisioning, regulating, cultural and supporting services (four qualitatively different categories of ecosystems services, defined by the Millennium Ecosystem Assessment 2005) are indicated in the figure below.
Why a plural approach to the recognition of the values of mahseer matters
Recognition of this diverse and broad range of ecosystem service benefits is helpful for describing the diversity of values provided by mahseer fishes and their supporting habitats, particularly to non-specialist public and policy-making communities. This in turn bolsters awareness of and support for the conservation of these iconic fishes and of the wider ecosystems upon which they are reliant.
This is particularly important in terms of broader ecosystem protection contexts. Freshwater ecosystems are disproportionately vulnerable, with an 84% decline in freshwater vertebrate populations reported in the 50 years to 2020. Freshwater fishes are amongst the most threatened taxa globally, particularly with migratory and megafauna fishes in alarming decline. This dramatic decline in freshwater biodiversity represents a largely unseen crisis, as it is often invisible to the general public and policy-makers.
This despite the significant role played by fish and fisheries for local communities throughout the world, and the economic and social benefits for all those millions who depend upon freshwater ecosystems for nutrition, income, recreational and cultural services.
Demonstrating that functioning ecosystems are vital for human well-being promotes recognition that conservation of nature is fundamental to supporting societal needs, including playing an underpinning role in the delivery of the United Nations' Sustainable Development Goals (SDGs).
Despite this, current trends in exploitation of freshwater resources, including fishes, represent a failure to adequately value and protect these systems, and the vital ecosystem services they provide, a shortfall addressed in the research reported in the new paper.
Assessment of the broad range of ecosystems services to which mahseer contribute is an approach that could usefully be applied to promote the benefits of conserving other 'umbrella' taxa - be they mammalian, vegetative or fungal, coastal, avian, herpetological or other - and the functional habitat that support them.