TY - JOUR
T1 - Trophic partitioning of sympatric zooplanktivorous silverside in a tropical shallow lake
T2 - Fish morphometry and diet composition
AU - Moncayo-Estrada, Rodrigo
AU - Lind, Owen T.
AU - Escalera-Gallardo, Carlos
PY - 2010
Y1 - 2010
N2 - This study examined diet composition, selection, and trophic morphology among three zooplanktivore silverside fishes (Chirostoma spp.) in an attempt to describe niche partitioning among closely related species in the tropical, shallow Lake Chapala, Mexico. To emphasize species interactions, sampling was carried out at the peak of the dry season (May) when a concentration effect was expected to take place as a consequence of lake volume reduction. Prey selection differed among species: Chirostoma consocium selected cyclopoid and calanoid copepods; C. jordani selected Bosmina and Diaphanosoma; C. labarcae selected Daphnia and Ceriodaphnia. Larger fishes occasionally consumed Hemipteran larvae. Although two Chirostoma species preyed upon the same zooplankton species, prey selection was consistent across size classes. From a total of 32 morphometric and meristic characteristics related to trophic ecology, 13 characteristics differentiated species, according to the discriminant analysis. Ordination including 11 morphometric characteristics and six zooplankton food items graphically separated the three species. The first axis separated species according to prey classes (copepods vs. cladocerans) and gross morphology (head and anal fin lengths). The second axis emphasized size-selective predation on cladocerans (Bosmina vs. Daphnia consumers) and fine trophic morphology (oral gape and the gill rakers' structure). Our findings suggest that the permanence of all three species in a fluctuating environment is the result of the circumvention of competition by niche partitioning, promoted by prey availability, selective predation, and few but critical differences in trophic morphology.
AB - This study examined diet composition, selection, and trophic morphology among three zooplanktivore silverside fishes (Chirostoma spp.) in an attempt to describe niche partitioning among closely related species in the tropical, shallow Lake Chapala, Mexico. To emphasize species interactions, sampling was carried out at the peak of the dry season (May) when a concentration effect was expected to take place as a consequence of lake volume reduction. Prey selection differed among species: Chirostoma consocium selected cyclopoid and calanoid copepods; C. jordani selected Bosmina and Diaphanosoma; C. labarcae selected Daphnia and Ceriodaphnia. Larger fishes occasionally consumed Hemipteran larvae. Although two Chirostoma species preyed upon the same zooplankton species, prey selection was consistent across size classes. From a total of 32 morphometric and meristic characteristics related to trophic ecology, 13 characteristics differentiated species, according to the discriminant analysis. Ordination including 11 morphometric characteristics and six zooplankton food items graphically separated the three species. The first axis separated species according to prey classes (copepods vs. cladocerans) and gross morphology (head and anal fin lengths). The second axis emphasized size-selective predation on cladocerans (Bosmina vs. Daphnia consumers) and fine trophic morphology (oral gape and the gill rakers' structure). Our findings suggest that the permanence of all three species in a fluctuating environment is the result of the circumvention of competition by niche partitioning, promoted by prey availability, selective predation, and few but critical differences in trophic morphology.
UR - http://www.scopus.com/inward/record.url?scp=77957372379&partnerID=8YFLogxK
U2 - 10.1643/CE-08-024
DO - 10.1643/CE-08-024
M3 - Artículo
SN - 0045-8511
SP - 431
EP - 436
JO - Copeia
JF - Copeia
IS - 3
ER -