DOI: 10.5061/dryad.gxd2547xg
title: Functional traits and stable isotopes reveal trophic interactions in a highly invaded reservoir: implications for fisheries

description: Aquatic ecosystems worldwide face significant threats, with human
 activities and biological invasions reshaping their dynamics and
 structure. Invasive species are among the biggest threats in freshwater
 ecosystems and cost to the global economy billions every year. Dams, even
 if human created, serve as species reservoirs and provide multiple
 ecosystem services. This study investigates the functional diversity and
 trophic ecology of the fish assemblage in the Zimapan dam in Mexico, a
 highly disturbed ecosystem that receives wastewater from one of the
 world's megacities along with industrial discharges. We focused on
 species coexistence, ecological niches, and the impact on local fisheries
 of tilapia. We identified eight species and two subspecies inhabiting this
 dam, only one of which is native, and observed functional complementarity
 among them. However, we observed trophic niche overlap, particularly
 between tilapia and other species, suggesting potential competition for
 resources. Our findings suggest that black bass predation, introduced for
 recreational fishing, is contributing to the decline of tilapia fisheries,
 a crucial economic activity for local communities. We provide
 recommendations for managing this complex ecosystem, emphasising the
 importance of continuous monitoring and regulation to sustain both
 biodiversity and human livelihoods.
description: # Functional traits and stable isotopes reveal trophic interactions in a
 highly invaded reservoir: implications for fisheries DOI:
 [https://doi.org/10.5061/dryad.gxd2547xg](https://doi.org/10.5061/dryad.gxd2547xg) --- ## Description of the data and file structure This dataset accompanies a study assessing the functional diversity, trophic structure, and fishing dynamics of the fish community in the Zimapán Reservoir, Mexico. The data are structured in three files: 1. Stable_Isotopes.csv – Stable isotope values of fish muscle tissues. 2. Ecomorphology.csv – Functional trait data based on morphological measurements. 3. Fisheries.csv – Daily fishing catch records from the “13 de Junio” cooperative. --- ## File: Stable\_Isotopes.csv **Description**: carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values from 90 individuals of ten fish species. **Variables**: * Species: Scientific name of each individual (e.g., Oreochromis spp., Lepomis macrochirus). * Standard length (mm): Measured from snout to caudal peduncle. * δ13C: Carbon isotopic ratio (‰), indicates the source of primary production in the food web. * δ15N: Nitrogen isotopic ratio (‰), used to infer trophic position within the food web. --- ## File: Ecomorphology.csv **Description**: Functional trait data derived from 21 morphological measurements on adult individuals, following Villéger et al. (2010), and grouped into ecomorphological indices related to locomotion and food acquisition. **Variables**: * Species: Scientific name. * Locomotion traits: The first 10 columns contain ecomorphological indices related to the locomotion function of fish. * Food acquisition traits: The last 4 columns contain ecomorphological indices related to the food acquisition function of fish. --- ## File: Fisheries.csv **Description**: Daily fishing logbook data from 7,541 records collected between July 2019 and October 2023. **Variables**: * Year: Calendar year of catch (e.g., 2020). * Month: Numerical month (1–12). * Week: Week number within the year. * Day: Day of the month. * Species: All records correspond to Tilapia (Oreochromis spp.), the commercially important species. * Kilograms: Total biomass (kg) caught per fisher, per day.