Worldwide Appraisal of Knowledge Gaps in the Space Usage of Small Pelagic Fish: Highlights Across Stock Uncertainties and Research Priorities

Le résumé fourni par la source

Understanding the spatial structure of life cycle components of small pelagic fish (SPF) stocks is key for deciphering population dynamics and ensuring sustainable management. The spatial extent of different life stages and ecologically relevant processes (e.g., reproduction) is temporally dynamic and responds to environmental, genetic, and demographic constraints. Knowledge gaps on within-stock spatial variability of key life cycle processes for SPF worldwide were identified for clupeoid fish (Clupeidae/Engraulidae). From the 3229 Web of Science-indexed articles reviewed, data were systematically extracted from 299. This information was supplemented with another 105 documents and databases from official SPF surveys and stock assessments. Overall, this review compiled information from 111 datasets (77 stocks) involving 17 assessed or commercially relevant species across 19 Large Marine Ecosystems (LMEs) and 38 coastal ecoregions. Only approximately 40% of the stocks used in this study covered the known or presumed stock distribution for at least one life-cycle variable: Adults (feeding area, spawning migration, feeding migration, overwintering migration, spawning area, and presence/biomass), juveniles (presence/biomass, nursery area), and larvae (larval routes). Despite more extensive spatial information from some Eastern Boundary Upwelling Systems (EBUS) and long-managed stocks, some important gaps remain due to information quality, stock identity ambiguity, or spatial data biases. Key information on SPF spatial variability could be extracted from existing surveys, but there were various limitations due to data access and spatiotemporal coverage. The main consequences of the key identified gaps are reviewed, and a series of priority research/monitoring actions are recommended to mitigate these consequences and improve our ability to address spatial variability in SPF stocks.

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