Spatial-temporal analysis of the diet of a non-native fish in the Santa Cruz Reservoir, Brazilian semi-arid

Jônnata Fernandes De Oliveira,Marla Melise Oliveira De Sousa,Danielle Peretti,José Luís Costa Novaes,Jean Carlos Dantas De Oliveira,Antonia Elissandra Freire De Souza,Andréa Bezerra Dos Santos

doi:10.1590/s2179-975x10416

Abstract

Abstract Aim The diet of Plagioscion squamosissimus present in the Santa Cruz Reservoir, Rio Grande do Norte, Brazil, was investigated, evaluating the influences of spatial and temporal variations and abiotic factors in the utilization of food resources. Methods The samplings were performed quarterly between February 2011 and November 2014. Of the 525 specimens captured, 375 presented food items in the stomachs. The diet was determined using: (i) Feeding Index (IAi); (ii) and the graphical interpretation of the food strategy through non-metric multidimensional scaling (NMDS) analyzes, the differences in diet being tested from Permutational Multivariate Analyzes of Variance (PERMANOVA). To verify if environmental variables influence the Canonical Correspondence Analyzes (CCA) were used, using the data from the IAi the environmental data, being the significance of the axes tested through Monte Carlo simulations. Results The species feed mainly on items of animal origin, vegetable being a resource ingested accidentally. The diet was composed of shrimp, fish, insect, mollusk and vegetable, the latter rarely found. The shrimp was the main item (92.57%) and the insects (7.24%) accessory items. Spatial and temporal ordering demonstrated that the species didn’t present variation in diet composition, as well as a low association between diet and environmental variables. Conclusion P. squamosissimus is characterized as carcinophagous, due to the predominance of shrimp in its diet, evidencing that the species is adapted to the conditions offered by the Brazilian semi-arid environment.

Highlights

In aquatic environments, variations in temperature, water level and rainfall are common throughout the year, resulting in cyclical changes in the abundance of available food, resulting in changes in fish diet (Oliveira et al, 2016a; Souza et al, 2017)
The diet was determined using: (i) Feeding Index (IAi); (ii) and the graphical interpretation of the food strategy through non-metric multidimensional scaling (NMDS) analyzes, the differences in diet being tested from Permutational Multivariate Analyzes of Variance (PERMANOVA)
To verify if environmental variables influence the Canonical Correspondence Analyzes (CCA) were used, using the data from the IAi the environmental data, being the significance of the axes tested through Monte Carlo simulations

Summary

Introduction

Variations in temperature, water level and rainfall are common throughout the year, resulting in cyclical changes in the abundance of available food, resulting in changes in fish diet (Oliveira et al, 2016a; Souza et al, 2017). Hydrological variations are responsible for the quantitative and qualitative changes in the availability of food resources, and at certain times some food sources undergo rapid changes becoming scarce or abundant, such as in the rainy season (Gandini et al, 2012; Silva et al, 2012). Another important factor to consider is the great spatial-temporal heterogeneity found in these environments, since in high water periods new habitats for feeding, in which the fish frequently pass, influencing the type of food ingested and the abundance of fish (Loures & Pompeu, 2012; Gandini et al, 2014). An important point is that the success of introduced species implies, for the most part, competition, predation, inhibition of reproduction, modification of the environment, transfer of parasites or diseases and hybridization (Agostinho et al, 2007)

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