Resolving the variability in habitat use by juvenile small pelagic fish in a major tidal system by continuous echosounder measurements

Marine Ecology Progress Series, Journal Year: 2023, Volume and Issue: 741, P. 169 - 187

Published: July 10, 2023

Shallow coastal areas are important nurseries for larvae and juveniles of many fish species. However, empirical data on small pelagic (SPF) in such regions lacking, temporal variability abundance habitat use by SPF unknown. Given the critical role as a trophic link, their commercial value sensitivity to climate variability, there is need quantitative high-resolution monitoring method. We deployed bottom-mounted echosounder, combined with water current profiler, examine variation density, vertical distribution movement behaviour Marsdiep, dynamic tidal inlet between North Sea Wadden Sea. The acoustic setup provided year-round records density column every 90 min. Monthly samples were collected help interpret observations. Our analyses indicated that Marsdiep migration gateway from into Sea, particularly juvenile herring sprat. observed clear seasonality high densities mid-spring early autumn. Fish typically used upper half column. Swimming was primarily driven currents. Yet, during outgoing tide, resisted outflowing current, suggesting efforts remain supporting hypothesis serves preferred nursery area SPF. frequency, multi-seasonal vertically resolved observations provide unique insight Furthermore, potential applications autonomous echosounder moorings discussed.

Language: Английский

Effect of eDNA metabarcoding temporal sampling strategies on detection of coastal biodiversity

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 12

Published: Feb. 7, 2025

Introduction Environmental DNA (eDNA) metabarcoding of water is increasingly being used to monitor coastal biodiversity shifts. However, we have limited knowledge whether samples collected during discreet temporal periods depict holistic ecosystem changes over longer time spans. Methods Here, show how eDNA community structure varies across repeated sampling events at different scales ranging from years months days an Arctic site, Churchill (Canada), using analyses with four universal primer pairs (two primers in COI and two the 18S rRNA). Results Daily variations were highly dynamic less structured, likely due stochastic nature estuarine ecosystems, but there was a clear annual consistency communities high proportion shared taxa between years. monthly most efficient for capturing biodiversity. Discussion We provide recommendations optimal design based on our observations. The study underscores importance understanding biological physical factors altering detection improve efficiency detecting interpreting long-term changes.

Language: Английский