Small pelagic fish in the new millennium: A bottom-up view of global research effort

Abstract Small pelagic fish (SPF) play extremely important ecological roles in marine ecosystems, form some of the most economically valuable fisheries resources, and a vital role global food security. Due to their short generation times tight coupling lower trophic levels, populations SPF display large boom-and-bust dynamics that are closely linked climate variability. To reveal emerging research trends on as opposed more recently published, ecosystem-specific reviews SPF, we reviewed literature published two, 6-year periods new millennium (2001–2006, 2011–2016) straddling publication large, review 2009. We explored intrinsic extrinsic (bottom-up) factors influencing such anchovies, sardines, herrings sprats within sub-order Clupeidae. Published efforts 16 different biogeographic ocean regions were compiled (more than 900 studies) compared identify i) milestones advances our understanding, ii) iii) remaining gaps knowledge. Studies separated into 5 categories (field, laboratory, mesocosms, long-term statistical analyses spatially-explicit modelling) discussed relation 10 bottom-up including abiotic (temperature, salinity, pH, dissolved oxygen, density), 3 physical processes (advection, turbulence, turbidity) 2 biotic (prey quantity quality). The peer-reviewed reflects changes number studies between two time increases (Mediterranean Sea, Humboldt Current) decreases (Australia, Benguela Current). Our highlights knowledge young juveniles and, general, impacts hypoxia heatwaves utility paleo exploring population drivers, continued need develop spatially-explicit, full life-cycle models, iv) importance how density-dependent impact rates (growth, survival, reproduction), v) benefits international collaboration for transfer building unifying hypotheses regulate populations.