Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions

Abstract

The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance.

Impact of Hydrographic Network Organization on the Morphology of the Kert Basin: Analysis of Consequences

“…Watersheds, intricate hydrological ecosystems, reflect the interplay between geographical and hydrographic factors, influencing unique environmental characteristics [1][2][3]. Focused on the Kert basin in the Eastern Rif, our study explores the intrinsic connection between morphology and the specific organization of its hydrographic network [1,4,5].…”

“…Watersheds, intricate hydrological ecosystems, reflect the interplay between geographical and hydrographic factors, influencing unique environmental characteristics [1][2][3]. Focused on the Kert basin in the Eastern Rif, our study explores the intrinsic connection between morphology and the specific organization of its hydrographic network [1,4,5]. By shedding light on these complexities, we draw insightful conclusions regarding environmental repercussions and implications for the communities in the Kert basin, contributing to a nuanced understanding of watersheds in the broader context of sustainable water resource management [6][7][8].…”