Fish Assemblage Structure Indicates Limited Restoration Progress over a Lustrum of a Severely Degraded Estuary in Southern Tamaulipas, Mexico

Abstract

Today the biggest incentive to attempt the restoration and protection of estuarine systems is their widely recognized ecological and economic importance. In the reconstruction of an estuary where the original aquatic communities disappeared before the restoration interventions, the fish assemblage is an adequate source of indicators of initial recovery. Following substantial restoration efforts, this study reports on the biannual for a lustrum monitoring and assessment of a severely degraded estuary (Garrapatas) in terms of its fish assemblage using a reference estuary (Barberena) in Tamaulipas, Mexico. Twenty fishes were associated with the restoring and reference estuaries. Species composition (richness, abundance, dominance) clearly showed differences among sites. No piscivorous estuarine or marine fishes were found in Garrapatas pointing at an unbalanced and incomplete trophic chain. On the other hand, the mangrove plant community appears to have fully recovered. Water parameters were more variable in Barberena compared to the restoring sites, especially salinity, DO, and pH, which were also higher. Estuaries are transitional systems with inherent variation of abiotic parameters. It is proposed that this variability of abiotic parameters still missing in the restored sites, and may be key to the full recovery of biotic assemblages and ecosystem function.