Effects of dams on demographic structures of amphidromous fish and crustacean species in Caribbean rivers

Frotté L., Cordonnier S., Bezault E., Monti D.

Published date: June 2020
Volume: 44
Number: 2
Pagination: 113-125
Publisher: Société Française d’Ichtyologie
doi: https://doi.org/10.26028/cybium/2020-442-003

Caribbean island rivers are the home to migratory indigenous macro-fauna. Concurrently, they also serve as the main source of freshwater for human consumption. This production of drinking water involves the construction of a large number of structures across the riverbed, which can slow or even stop the migration of aquatic species. The resident river macro-fauna is composed of crustacean and fish species that all have a diadromous and mostly amphidromous life cycle, involving pro-larval drift downstream towards the sea, marine larval dispersal, followed by an upstream river migration to complete their growth and reproduction cycle. Our study compares, across three rivers on the island of Guadeloupe, the recruitment of five crustacean species and two fish species in the mouths of these rivers with species demographic distributions on either side of the major water withdrawal structure built along these rivers. Post-larval recruitment events were multispecific, discrete over time and their amplitude varied depending on the river. We show differential biological porosity of each obstacle according to species, revealing different specific crossing abilities. Our results also suggested that the impacts were not directly related to the height of the structure but that external, hydrological and environmental, conditions are involved. These achievements can be translated into operational measures such as the maintaining and monitoring of reserved minimal flows that are adapted to passways, as well as the setting up of protective measures for the natural environment

Keywords: Atyidae - Freshwaters - Guadeloupe - Palaemonidae - Sicydiinae - Upstream migration
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