Trophic interactions among sympatric zooplanktivorous fish species in volume change conditions in a large, shallow, tropical lake

Rodrigo Moncayo-Estrada,Owen T Lind,Carlos Escalera-Gallardo

doi:10.1590/s1679-62252011005000003

Rodrigo Moncayo-Estrada, Owen T Lind + Show 1 more

Open Access

https://doi.org/10.1590/s1679-62252011005000003

Copy DOI

Abstract

Significant reductions in the water volume of shallow lakes impose a restriction on species segregation promoting more interactions in the trophic relationships. The diets of three closely related zooplanktivorous silversides belonging to the Atherinopsidae species flock of lake Chapala , Mexico, were analyzed at two sites (Chirostoma jordani, C. labarcae, and C. consocium). Diets were described in critical shallow (August 2000) and volume recovery conditions (August 2005). Diets included mainly cladocerans (Bosmina, Ceriodaphnia, and Daphnia) and copepods (Cyclops). A significant difference in diets was detected when comparing years (MRPP analysis, A = 0.22, p < 0.0001) and sites at different years (MRPP analysis, A = 0.17, p = 0.004). According to niche breadth mean values, species were classified as specialized and intermediate feeders. In shallow conditions, the small range of niche breadth (1.72 to 3.64) and high diet overlap values (D = 0.64, L = 8.62) indicated a high potential for interspecific exploitative interaction. When the lake volume recovered, an increase in the niche breadth range (1.04 to 4.96) and low niche overlap values (D = 0.53, L = 2.32) indicated a reduction of the species interaction. The Mann-Whitney U-test supported this pattern by showing a significant difference between years for niche overlap (p = 0.006). The increased interaction during the low volume suggests alternative segregation in life-history variations and other niche dimensions such as spatial or temporal distribution.

Highlights

IntroductionTrophic relationships among fish species comprising feeding guilds have been examined in different aquatic ecosystems (Emery, 1973; Ross, 1986)
The study of diet interactions in ecological studies helps address questions such as the niche partitioning among closely related species (Richards et al, 2000; Carvalho & Gomes, 2004), provides key elements in understanding the predator and prey relationships (Liao et al, 2002) and enables modeling the effect of environmental changes on an aquatic community’s trophic interactions (Kuroda et al, 2005).Trophic relationships among fish species comprising feeding guilds have been examined in different aquatic ecosystems (Emery, 1973; Ross, 1986)
Trophic interactions among sympatric zooplanktivorous fish species change conditions, those fish that belong to the zooplanktivorous fish guild in tropical shallow lakes

Summary

Introduction

Trophic relationships among fish species comprising feeding guilds have been examined in different aquatic ecosystems (Emery, 1973; Ross, 1986). In tropical lakes these relationships had been described according to habitat heterogeneity (Genner et al, 1999; Sibbing & Nagelkerke, 2001), seasonal patterns (Furse et al, 1979; Sampaio da Silva et al, 2005) and alteration processes (Lévêque, 1997; Piet, 1998). Trophic interactions among sympatric zooplanktivorous fish species change conditions, those fish that belong to the zooplanktivorous fish guild in tropical shallow lakes. The co-occurrence of these three similar species in lake Chapala suggests that some means of partitioning habitat and trophic resources must exist

Objectives

Methods

Results

Conclusion