Field data for fishes sampled using bottom and surface gill nets during daylight hours in Clear Lake, California, USA. This data release includes all measured environmental parameters and fish taxa included in the analysis. First posted - December 20, 2018 (available from author) Revised - November 26, 2019 (version 2.0) Revised - January 21, 2022 (version 3.0) Revised - October 11, 2022 (Version 4.0)

Field data for fishes sampled using bottom and surface gill nets during daylight hours in Clear Lake, California, USA. This data release includes all measured environmental parameters and fish taxa included in the analysis. First posted - December 20, 2018 (available from author) Revised - November 26, 2019 (version 2.0) Revised - January 21, 2022 (version 3.0) Revised - October 11, 2022 (Version 4.0)

Revision of field data release for fishes sampled using bottom and surface gill nets during daylight hours in Clear Lake, California, USA. This data release includes all measured environmental parameters and fish taxa included in the analysis and the revision involves appending the newest year of data to the release. First posted - November 8, 2023 Revised - December 18, 2024 (version 2.0) Revised - December 4, 2025 (version 3.0)

Field data for fishes sampled using bottom and surface gill nets during daylight hours in Clear Lake, California, USA. This data release includes all measured environmental parameters and fish taxa included in the analysis.

The dataset includes four seperate files of data for a project that examined the strontium isotopic composition of otoliths of Clear Lake Hitch. Otoliths examined in this study were from randomly-sampled individual Clear Lake Hitch that recruited into the adult population in Clear Lake. The fish were collected in June and July 2017. Strontium isotopic composition (87Sr/86Sr ) in otoliths was determined with a multicollector LA-ICP mass spectrometer (LA-ICMPS; Nu Plasma HR, Nu Instrument, Inc.) interfaced with a Nd : YAG 213-nm laser (New Wave Research UP213) at the University of California, Davis. Fish capture and size data are in the file Clear Lake Hitch Otolith Data_FISH. Otolith increment data are in the file Clear Lake Hitch Otolith Data_INCREMENT. Strontium isotopic data are in the file Clear Lake Hitch Otolith Data_STRONTIUM. Laboratory standard data are in the file Clear Lake Hitch Otolith Data_STANDARD.

Field data for vertical water quality profiles using Yellow Spring Instruments (YSI) EXO2 sondes during daylight hours in Clear Lake, Lake County, California. This data release includes all measured environmental parameters included in the analysis. First release: April 13, 2019 Revised: October 29, 2019 (version. 2.0) Revised - January 24, 2022 (version 3.0) Revised - May 31, 2024 (version 4.0)

Field data for vertical water quality profiles using Yellow Spring Instruments (YSI) EXO2 sondes during daylight hours in Clear Lake, Lake County, California. This data release includes all measured environmental parameters included in the analysis. First release: April 13, 2019 Revised: October 29, 2019 (version. 2.0) Revised - January 24, 2022 (version 3.0) Revised - May 31, 2024 (version 4.0)

This data release includes a collection of photographs and video clips. Above water observations were taken with with a Nikon D5300 digital camera and underwater observations were taken with a SOOCOO S100Pro digital camera. All observations were made on April 1, 2018 in Kelsey, Creek, Lake County, California. Further details can be found in: Feyrer, F. 2018. Rapid potamodromy into ephemeral streams: observations of the spawning ecology of the imperiled Clear Lake Hitch Lavinia exilicauda chi. (in review)

Clear Lake, located within the Coast Range west of California's Central Valley, is the largest natural freshwater lake contained fully within the state. The lake has three arms: a large open-water region to the northwest (Upper Arm), a smaller and narrower region to the southeast (Lower Arm), and the smallest and narrowest region to the east (Oaks Arm). Water quality in Clear Lake is degraded by both by mercury contamination and harmful algal blooms (HABs). The mercury contamination is largely associated with the Sulfur Bank Mercury Mine (SBMM), a Superfund site managed by the U.S. Environmental Protection Agency (USEPA) since 1992 located on the eastern end of the Oaks Arm. Mercury contamination from SBMM and its biogeochemical mercury cycling within the lake are the focus of research being conducted by the U.S. Geological Survey (USGS) in cooperation with USEPA. Monitoring and modeling efforts are being implemented to improve understanding of the ways that nutrient dynamics affect the cycling, transport, and bioaccumulation of Hg. This data release documents measurements related to organic matter concentrations and characteristics in Clear Lake, California. Data files reported here provide full spectral results for absorbance (Clear_Lake_Full_Spectra_Absorbance_Data.csv) and fluorescence (Clear_Lake_Vectorized_Fluorescence_Data.csv) analyses as well as calculated fluorescence indices and arrays (Clear_Lake_Sample_Summary.csv) used for statistical modeling for proxy development. Commonly reported diagnostic absorbance wavelengths and fluorescence excitation-emission pairs contained in these spectra as well as a set of commonly calculated indices have been released to the USGS National Water Information System (NWIS) database. The optical measurements reported here were collected to establish additional potential surrogates for mercury (Hg) and methylmercury (MeHg) concentrations and to provide more complete spectral information on temporal and spatial patterns of organic matter within the lake. Other water-quality data for the samples included in this data release are published in Marvin-DiPasquale and others (2020) and Agee and others (2024).

The dataset includes water temperature and atmospheric pressure data collected from selected key tributaries Clear Lake, Lake County, California, used for spawning by the Clear Lake Hitch (Lavinia exilicauda chi): Kelsey Creek, Siegler Creek, Middle Creek, Adobe Creek, and Cole Creek. Data were collected with ONSET HOBO Model U20L-002 loggers.