ĭespite the diverse array of benefits they provide, many floodplain wetland habitats around the world have been heavily degraded by channelization, water diversion and conversion to agricultural lands. This nursery function stems from the shallow ephemeral nature of inundated floodplain wetlands, providing refuge from large predators and high densities of prey for rapid growth. In coastal systems, floodplain wetlands can function as productive nursery habitats for fish exhibiting a diversity of life histories. Meanwhile, floodplain inundation during wet seasons can increase in-situ productivity as well as deliver sediment, nutrients and productivity downstream, providing a mosaic of inter-connected riverine, floodplain and estuarine landscapes. During dry seasons, floodplain wetlands exist as shallow channel habitats that can act as hotspots of local primary and secondary productivity, sequester large amounts of carbon, and provide drought refugia for wildlife. It will likely require a mosaic of habitats that incorporates floodplain-tidal sloughs in order to promote the resilience of this declining estuarine fish species.įloodplain wetlands are highly dynamic environments, located at the interface of lowland-riverine and coastal ecosystems that play a crucial role in estuarine productivity. However, our results also demonstrated that no single region provided the best rearing habitat for juvenile Delta Smelt. The occurrence of healthy juvenile Delta Smelt in the Yolo Bypass suggested that the region may have acted as a refuge for the species during the drought years of 2012–2016. Our results indicated that when compared to other areas of the estuary, fish in the Yolo Bypass spawned earlier, and offspring experienced both higher quality feeding conditions and growth rates. To determine the value of the Yolo Bypass as a nursery habitat for Delta Smelt, we compared growth, hatch dates, and diets of juvenile Delta Smelt collected within the Yolo Bypass with fish collected among other putative nursery habitats in the San Francisco Estuary between 20. Meanwhile, Delta Smelt abundance elsewhere in the estuary was at record lows during this time. During the recent drought (2012–2016), we found higher abundance of the endangered Delta Smelt ( Hypomesus transpacificus), than the previous 14 years of fish monitoring within the Yolo Bypass. However, the Yolo Bypass exists as a tidal dead-end slough during dry periods and its value to native fishes has been less studied in this state. The Yolo Bypass, the primary floodplain of the Sacramento River in California’s Central Valley, USA, has been shown to provide various benefits to native fishes when inundated.
Seasonal floodplain wetland is one of the most variable and diverse habitats found in coastal ecosystems, yet it is also one of the most highly altered by humans. Those interested can access the data via the provided links in the same manner as the authors. The Summer Townet Survey, 20-mm Survery Fish catch data, and the Water Temperature data are are not owned nor collected by the authors of this study.
Water temperature data is available from California Department of Water Resources website ( ). Available from: Summer Townet Survey and 20-mm Survey fish catch data are available from California Department of Fish and Wildlife website ( ). Interagency Ecological Program: Fish catch and water quality data from the Sacramento River floodplain and tidal slough, collected by the Yolo Bypass Fish Monitoring Program, 1998-2018 2018. Fish catch data from the Yolo Bypass is available on the Environmental Data Initiative website: Interagency Ecological Program (IEP), Schreier B, Davis B, Ikemiyagi N. Growth and diet data are provided in the Supporting Information files.
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