Effect of Substrate Type and Fish Activity on Freshwater Meiofaunal Colonization

CONTEXT. Meiofauna are a natural food source for higher aquatic organisms. However, their colonization (abundance and biomass) response to substrate type and perturbation needs to be explored. Aims. The study investigated how meiofaunal colonization (MC) was affected by substrate type (organic and inorganic as artificial substrates (AS), and natural sediment as a control) and ascending fish activity (FA), representing disturbance. Methods. This study was divided into three two-month periods depicting (FA) escalation between November 2021 and April 2022. Nine replicates of organic and inorganic substrates were positioned at the beginning of each period and recollected after a two-week colonization period, plus nine more replicates of the natural sediment cores. Environmental variables were evaluated. Key results. Despite the insignificant difference between the (AS) in terms of (MC), it significantly differed from that of the natural substrate within each period. However, (MC) significantly differed among the three (FA) periods, except for those of the natural substrate. Furthermore, the third (FA) had the lowest (MC) for all substrates. Conclusions. (MC) in (AS) protected from fish predation and/or disturbance, enhancing meiofaunal proliferation and mucus secretion, creating diverse micro-niches promoting colonization. Implications. Meiofaunal proliferation may enhance the fish nutrition sustainability in aquaculture. However, further research is needed to optimize this strategy.