Realm: Freshwater
Climate: Temperate
Biome: Small river ecosystems
Central latitude: 38.109270
Central longitude: -121.908540
Duration: 26 years, from 1995 to 2020

85684 records

20 distinct species

Across the time series Pseudodiaptomus is the most frequently occurring species

Methods

Curators note: The original IEP zooplankton dataset has been split by the different survey programmes due to methodological differences. The Interagency Ecological Program (IEP) is a consortium of State and federal agencies that has been conducting cooperative ecological investigations since the 1970s. The IEP runs over twenty long-term monitoring surveys on biological components of the Upper San Francisco Estuary. Surveys monitor phytoplankton, zooplankton, benthic invertebrates, water quality, and many types of fish. Several fish surveys sample zooplankton concurrently, and information on zooplankton species composition and abundance can be coupled with fish diet studies. The IEP long-term surveys that monitor zooplankton are the Environmental Monitoring Program (EMP; also known as the IEP zooplankton study), 20-mm Survey (20mm), Fall Midwater Trawl (FMWT), Summer Townet Survey (STN), the Yolo Bypass Fisheries Monitoring Survey (not included in this integrated dataset), and the Fish Restoration Program (FRP). An overview of these programs is provided in study_metadata.csv. Locations of fixed sampling locations for surveys with fixed sampling designs are provided in stations.csv, and coordinates for every sample are provided in environment.csv. Zooplankton surveys sample 3 different size classes of zooplankton, by towing nets with different sized mesh (or in one case a pump that pumps water into a microzooplankton net). Every IEP survey that collects zooplankton samples with a mesozooplankton net, which targets adult copepods and cladocerans, because these taxa are believed to comprise the majority of zooplankton in juvenile and adult planktivorous fish diets. Some surveys also sample with micro- or macro-zooplankton nets. Three size classes of zooplankton are targeted by these sampling programs with different net mesh sizes: micro zooplankton (copepods and rotifers) are targeted with a 43 µm mesh net, meso zooplankton (copepods and cladocerans) are targeted with 150 - 160 µm mesh nets, and macro zooplankton (mysids and amphipods) are targeted with 500-505 µm mesh nets. The 20-mm survey was initiated in 1995 by the California Department of Fish and Wildlife to monitor postlarval-juvenile Delta Smelt (Hypomesus transpacificus) distribution, abundance, and timing throughout their historical spring range in the Delta. The survey is mandated under the Endangered Species Act Biological Opinion for operation of the State and Central Valley water projects (USFWS 2019). 20-mm refers to the length of the fish targeted by the net. Zooplankton samples are collected concurrently with fish samples to monitor Delta Smelt food supply. Between 41 and 55 stations have been sampled each year since the survey began. Zooplankton are sampled twice per month between March and July at fixed stations in open channels. Mesozooplankton are sampled using 10-minute stepped-oblique tows with a 73 cm long 160 µm mesh modified Clarke-Bumpus net. The net is attached to the top of the 20-mm net frame and a flowmeter is mounted in the mouth. Samples are preserved in 10% formalin. Lengths are not recorded, and biomass is estimated by literature values. Recorded environmental variables include times, tidal stage, depth, surface and bottom conductivity, surface temperature, Secchi depth, and turbidity. More information on the 20-mm survey and its methods can be found on the 20-mm survey website (California Department of Fish and Wildlife 2021).

Citation(s)

@Dataset{BioTIME_cit332, Study_id = {555}, Citation_id = {332}, Author = {Bashevkin, S.M. and Hartman, R. and Thomas, M. and Barros, A. and Burdi, C.E. and Hennessy, A. and Tempel, T. and Kayfetz, K. and Alstad, K. and Pien, C.}, Publisher = {Environmental Data Initiative}, Title = {Interagency Ecological Program: Zooplankton abundance in the Upper San Francisco Estuary from 1972-2021, an integration of 7 long-term monitoring programs ver 4}, Year = {2023}, Doi = {10.6073/pasta/8b646dfbeb625e308212a39f1e46f69b}, Url = {https://doi.org/10.6073/pasta/8b646dfbeb625e308212a39f1e46f69b}, Language = {English}, Version = {4} }