Estimation of Fish Biomass Using Environmental DNA

Teruhiko Takahara,Toshifumi Minamoto,Hideyuki Doi,Zen'Ichiro Kawabata,Hiroki Yamanaka,Jack Anthony Gilbert

doi:10.1371/journal.pone.0035868

Teruhiko Takahara, Toshifumi Minamoto + Show 4 more

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https://doi.org/10.1371/journal.pone.0035868

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Abstract

Environmental DNA (eDNA) from aquatic vertebrates has recently been used to estimate the presence of a species. We hypothesized that fish release DNA into the water at a rate commensurate with their biomass. Thus, the concentration of eDNA of a target species may be used to estimate the species biomass. We developed an eDNA method to estimate the biomass of common carp (Cyprinus carpio L.) using laboratory and field experiments. In the aquarium, the concentration of eDNA changed initially, but reached an equilibrium after 6 days. Temperature had no effect on eDNA concentrations in aquaria. The concentration of eDNA was positively correlated with carp biomass in both aquaria and experimental ponds. We used this method to estimate the biomass and distribution of carp in a natural freshwater lagoon. We demonstrated that the distribution of carp eDNA concentration was explained by water temperature. Our results suggest that biomass data estimated from eDNA concentration reflects the potential distribution of common carp in the natural environment. Measuring eDNA concentration offers a non-invasive, simple, and rapid method for estimating biomass. This method could inform management plans for the conservation of ecosystems.

Highlights

Information about the distribution of a species is a critical component of understanding their ecology and extinction risks and is important for conservation of populations [1]
We evaluated the relationships between Environmental DNA (eDNA) concentrations in the aquaria and three factors
In the aquarium and pond experiments, we evaluated the relationship between eDNA concentration and biomass of carp per 1-L water sample using a Type II regression, and evaluated the relationship between the number of carp and biomass using a Type I regression

Summary

Introduction

Information about the distribution of a species is a critical component of understanding their ecology and extinction risks and is important for conservation of populations [1]. Environmental DNA (hereafter, eDNA) has been used to document the distributions of aquatic vertebrate species [2,3,4,5,6]. Absence/presence data can be used to illustrate species distribution, and eDNA has often been used to document presence/absence of aquatic species. Knowledge of species biomass is critical to estimate the production and material cycling of ecosystems [1]. Biomass information plays a major role in conserving rare and endangered species and in managing population sizes [1]. Assuming that aquatic vertebrates release eDNA into the water (from feces, secretions, or tissues) in proportion with their biomass, eDNA could be used to estimate species biomass by measuring the number of eDNA copies in a sample of water

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