Featured Survey
- Enhanced Delta Smelt Monitoring (EDSM)
The Enhanced Delta Smelt Monitoring (EDSM) program started its 2024 Phase 3 sampling program for juvenile and sub-adult Delta Smelt on July 1, 2024. In order to improve our ability to make inferences about the population, sampling effort is being focused on geographic areas where Delta Smelt are likely to be caught based on historical data. Sampling locations are generated using a generalized random-tessellation stratified (GRTS) design (Stevens 2004) with stratification and equal probability sampling. Trawling gear similar to that used in the California Department of Fish and Wildlife’s Spring Kodiak Trawl Survey is used to conduct multiple tows per site. More information regarding this survey and past reports can be found at website maintained by the U.S. Fish and Wildlife Service.
Featured Publications
- In an article titled: Stopping Rule Sampling to Monitor and Protect Endangered Species Mitchell, Polansky, and Newman discuss “a sequential adaptive sampling design focused on making population-level inferences while limiting harm to the target population. The design incorporates stopping rules such that multiple samples are collected at a site until one or more individuals from the target population are captured, conditional on the number of samples falling within a predetermined range. With this application in mind, we pair the stopping rules sampling design with a density model from which to base abundance indices.” The article can be found in the Journal of Agricultural, Biological, and Environmental Statistics.
- In an important contribution from Freshwater Biology to the topic of predation in California’s Delta, Nelson and 6 co-authors describe Anthropogenic and environmental risk factors of salmonid predation in a tidal freshwater delta, with the following objectives: “First, we determined if small water diversions aggregated piscivorous fishes like other similar structures in freshwater ecosystems. Second, we determined how small diversions may influence juvenile salmon predation risk in conjunction with other known predation risk factors (e.g. predator abundance, temperature and depth). Third, we assessed the predator assemblage, abundance and distribution to determine the likely predator composition in objectives one and two.”
- Also from Freshwater Biology is an article from Phillips and others titled: Forbs from seasonal managed wetlands boost plankton production more than emergent graminoids by supplying novel labile detritus. This original article discusses how the authors “proposed that decaying vegetation resulting from controlled flooding in managed wetlands is important for stimulating plankton blooms, but that the effect varies by plant species and functional type. We conducted a mesocosm experiment to test the effects of different inundated plants on plankton production, including three forb species, three emergent graminoid species and a control treatment without added plant material.”
Featured Dataset Publications
- The Interagency Ecological Program has updated one of its core sampling datasets as part of a data package available from the Environmental Data Initiative and the EDI Data Portal. From the Abstract: “The Enhanced Delta Smelt Monitoring Program (EDSM) was initiated by the U.S. Fish and Wildlife Service in 2016. EDSM focuses on providing real-time data to help managers respond to population patterns of Delta Smelt within the upper San Francisco Estuary, primarily by providing estimates of Delta Smelt distribution and abundance. The dataset can also be useful in evaluating habitat use and behavior patterns of this species and other fish species of interest. Sampling is done year round via Kodiak trawls and larval (“20-mm”) gear to sample Delta Smelt across most life stages. Sites are chosen via stratified random sampling. Over the course of a week, field crews sample between 18 and 41 random sites. A minimum of two tows are conducted at each site. All fish collected are identified (in the field, when possible, in the lab for early life stages), measured, enumerated, and recorded. In addition to fish information, environmental data are collected for each sampling event.” For more information, visit the Lodi Fish and Wildlife Office web page.
- Shruti Khanna and 10 colleagues have made available a dataset publication titled: The Sacramento-San Joaquin Delta genus and community level classification maps derived from airborne spectroscopy data. Available from knb ecoinformatics, the abstract for the data reads: “Since 2004, airborne hyperspectral imagery has been acquired over the Sacramento - San Joaquin Delta in northern California to map submerged and floating invasive species and study how they affect the Delta ecosystem. Acquiring imagery over 2220 square kilometers of the Delta typically required 60-70 flightlines each year, which were then further processed to surface reflectance, georegistered, and prepared for analysis. Further, each flightline was processed using multiple spectral mapping methods such as spectral angle mapper, spectral mixture analysis, spectral indexes, and continuum removal over water and cellulose absorption bands. The outputs of these transformations were used as inputs to a Random Forests classifier. Concurrent with image acquisition, field data (800-2000 points) were collected across the Delta for training and validation of the classification products. The field data were divided into test and training polygons. These polygons were overlaid on the transformed files and pixel data were extracted corresponding to the polygons. The training data were used to train the Random Forests classifier to identify 10 classes (water, submerged aquatic vegetation, emergent marsh, soil, non-photosynthetic vegetation, water hyacinth, water primrose, pennywort, shadow, riparian vegetation). The classifier was validated quantitatively using the test data at both pixel and polygon level using overall accuracy and kappa metrics. The classifier was then applied to all flightlines and class maps were produced. Mosaics of these class maps are published in this dataset.”
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