Ichthyoplankton Diversity and Spatial Turnover in the Neritic Zone of the Colombian Pacific (Eastern Tropical Pacific)

Larval fish assemblages provide critical insights into reproductive dynamics, biodiversity baselines, and ecosystem resilience, yet remain poorly documented in the Colombian Pacific. This study analyzed ichthyoplankton diversity and spatial turnover across six neritic localities sampled between 2008 and 2022. Standardized plankton tows yielded 43,277 larvae representing 291 morphospecies, 150 genera, 66 families, and 38 orders. The richness observed accounts for ~34% of fish species listed for the Eastern Tropical Pacific and 15% of adult bony fishes reported for the Colombian Pacific, exceeding previous records. Diversity patterns revealed pronounced spatial heterogeneity: Cupica emerged as a biodiversity hotspot, Pizarro and Tortugas were dominated by few taxa, and Sanquianga exhibited high evenness despite moderate richness. Beta diversity analyses indicated turnover exceeding 60% and dissimilarity surpassing 70%, underscoring strong locality identity shaped by oceanographic gradients, geomorphology, and estuarine dynamics. Dominance patterns highlighted contrasting ecological strategies, with cosmopolitan taxa such as Cetengraulis mysticetus coexisting alongside habitat-restricted species of Labrisomus. These findings establish the Colombian Pacific neritic zone as a reservoir of genetic and functional diversity, with high richness and turnover reinforcing its role in sustaining ecosystem functioning and fisheries productivity. Methodological handicaps—including reliance on morphology-based identification, formalin preservation limiting molecular analyses, and uneven temporal coverage—constrain taxonomic resolution, yet the ecological patterns observed provide a robust foundation for conservation planning. Future research integrating molecular tools, trait-based approaches, and long-term monitoring will be essential to refine diversity estimates and strengthen adaptive management under scenarios of climate variability and increasing anthropogenic pressures in the Eastern Tropical Pacific.