Veronica L. Violette Collin D. Smith Matthew J. Young Frederick V. Feyrer 20250513 tabular digital data https://www.sciencebase.gov U.S. Geological Survey Violette, V.L., V.L., Smith, C.D., Young, M.J., and Feyrer, F.V., 2025, Fish Observations During Delta Smelt Experimental Releases Inferred from ARIS Sonar: U.S. Geological Survey data release, https://doi.org/10.5066/P97GF01P https://doi.org/10.5066/P97GF01P This dataset includes post-processed data for underwater fish observations by using Acoustic Resolution Imaging Sonar technology in Montezuma Slough, Sacramento River, and in the Sacramento Deep Water Shipping Channel in the Sacramento-San Joaquin Delta, California, USA. This data release includes sample data associated with each video file collected, swimming behavior of groups of released cultured Delta Smelt (Hypomesus transpacificus) that is associated with all three release types, and tracking data on both released cultured Delta Smelt and ambient fish that were observed underwater using sonar technology. This data release includes data from years one to three of the Delta Smelt Experimental Releases, in water years 2022 to 2024. The Delta Smelt is an endangered fish species that is thought to be on the brink of extinction (Hobbs et al. 2017). Supplementation of the wild population with cultured fish is a vital step in preventing extirpation from the wild. Cultured Delta Smelt have never been released at liberty into the wild prior to this study, so there is considerable uncertainty in how the released fish will behave and how well they survive upon release. Cultured Delta Smelt and other ambient fish within the release location were observed using a non-invasive sampling method, Acoustic Resolution Imaging Sonar technology. The goal of this study was to observe the swimming behavior of released cultured Delta Smelt for the first time, and collect other tracking information on ambient fish observed within the area that Delta Smelt were released in. This data can be used to provide information for future releases of cultured Delta Smelt within the Sacramento-San Joaquin Delta. 20211215 20240130 ground condition Complete Irregular Sacramento-San-Joaquin Delta, Solano County, California -122.0533 -121.6502 38.2630 38.0913 ISO 19115 Topic Category biota USGS Thesaurus sonar methods animal tracking fish multibeam sonar Delta Smelt Acoustic Resolution Imaging Sonar ARIS animal behavior endangered species Aquatic Biology Ecology USGS Metadata Identifier USGS:64dc039ed34e5f6cd5524646 Common geographic areas United States California San Joaquin Delta Lower Sacramento Montezuma Rio Vista Integrated Taxonomic Information System (ITIS) delta smelt Kingdom Animalia Subkingdom Bilateria Infrakingdom Deuterostomia Phylum Chordata Subphylum Vertebrata Infraphylum Gnathostomata Superclass Actinopterygii Class Teleostei Superorder Protacanthopterygii Order Osmeriformes Suborder Osmeroidei Superfamily Osmeroidea Family Osmeridae Genus Hypomesus Species Hypomesus transpacificus TSN: 162032 None. Please see ‘Distribution Information’ section for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. It is requested that the suggested citation for this USGS data release be included in any publications that reference or utilize these data. Veronica Violette U.S. Geological Survey Fish Biologist mailing and physical

Suit 180

West Sacramento CA 95691 USA 916-716-7372 vviolette@usgs.gov U.S. Fish and Wildlife Service and California Department of Water Resources Data was field checked directly after the sample was completed and quality assurance/quality control (QAQC) was conducted post sampling according to Aquatic Ecology Group standard operating procedure. Data was field checked directly after the sample was completed and quality assurance/quality control (QAQC) was conducted post sampling according to Aquatic Ecology Group standard operating procedure. Data set is considered complete for the information presented, as described in the abstract. Users advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted. No formal positional accuracy tests were conducted. Echoview 2014 version 6.1 application/service Echoview software used to track individual fish Echoview, 2014, Echoview, version 6.1: Hobart, Australia, Echoview Software Pty Ltd, Accessed November 2020 at https://echoview.com/support/echoview-downloads/ https://echoview.com/support/echoview-downloads/ Digital and/or Hardcopy Unknown Still valid Echoview, 2014 Unknown M. Kang 2011 publication Kang, M., 2011, Semiautomated analysis of data from an imaging sonar for fish counting, sizing, and tracking in a post-processing application: Fisheries and Aquatic Sciences, v. 14, no. 3, p. 218–225, accessed November 7, 2020, at https://doi.org/10.5657/FAS.2011.0218 https://doi.org/10.5657/FAS.2011.0218 Digital and/or Hardcopy Unknown Still valid Kang, 2011 Unknown J. Hobbs 2017 publication Hobbs, J., Moyle, P., Fangue, N., Connon, R., 2017, Is extinction inevitable for Delta Smelt and Longfin Smelt?: San Francisco Estuary and Watershed Science, v. 15, no. 2. https://doi.org/10.15447/sfews.2017v15iss2art2 https://doi.org/10.15447/sfews.2017v15iss2art2 Digital and/or Hardcopy Unknown Still valid Hobbs et al. 2017 Unknown R Core Team 2014 version 4.0.3 application/service R Core Team, 2014, R—A language and environment for statistical computing, version 4.0.3: Vienna, R Foundation for Statistical Computing software release, accessed November 2022, at http://www.R-project.org/ http://www.R-project.org/ Digital and/or Hardcopy Unknown Still valid R Core Team, 2014 Unknown ARISFish 2020 version 2.8.0.2295 application/service ARISFish software used to observe Delta Smelt behavior ARISFish, 2020, ARISFish, version 2.8.0.2295: Bellevue, Washington, ARISFish Software, Accessed October 2021 at http://www.soundmetrics.com/My-Account/Downloads/ARIS/Software http://www.soundmetrics.com/My-Account/Downloads/ARIS/Software Digital and/or Hardcopy Unknown Still valid ARISFish, 2020 Unknown Field sampling was conducted during daylight hours in the Fall and Winter months for three water years. Year one sampling occurred between December 13, 2021 and February 17, 2022, year two sampling occurred between November 28, 2022 and January 26, 2023, and year three sampling occurred between November 15, 2023 and January 31, 2024. Sampling locations for all three years included in the Sacramento Deep Water Shipping Channel near channel markers 51 and 53 and the Sacramento River near Rio Vista, with sampling in Montezuma Slough near Belden's Landing only in year one. ARIS Explorer 3000 with an AR2 Rotator was used to observe fish underwater in a turbid environment. During hard and soft releases, where releases were conducted off-shore, ARIS units were mounted off the starboard side of the vessel using a Kentucky mount (https://www.usgs.gov/media/images/kentucky-mount-0). During trailer releases, where releases were conducted on-shore, ARIS units were either mounted on the dock at the launch ramp or on a sled mount along a beach. The sonar maintained a minimum four-degree tilt from the horizontal plane to avoid reflections from the water surface that create false signals (noise). The sonars were operated with laptop computers. Sonars and computers were powered by the vessel's house batteries (hard and soft releases) or generators (trailer releases). ARIS sonar video was collected a few hours to a couple days prior to Delta Smelt being released into the wild, during the release, and a couple of hours after Delta Smelt were released into the wild. Sonar was recording using default settings and the viewing frame changed depending on the depth and distance from the target. Recordings were set to record continuous data starting at minute zero, and create a new file every 15 minutes to keep file sizes manageable. Sample data was transcribed from paper data sheets into an Excel file. Field data was checked for errors in the field and quality assurance/quality control (QAQC) was conducted post data entry. QAQC entailed checking the data was entered in all applicable fields, checking for erroneous values, and consulting field staff involved in the sample if there was questionable data. Appropriate changes were then made and noted in the excel file by the reviewer. Spreadsheets were directly exported from Excel in .xlsx format. No data was screened from this data release. 2024 Veronica L. Violette USGS - SOUTHWEST REGION Fish Biologist mailing and physical

California Water Science Center,California District Office - Placer Hall

Sacramento CA 95819 916-278-3065 vviolette@usgs.gov Smelt behavior data is observational data collected during the post-processing of sonar video files performed with ARISFish software (ARISFish, 2020). The software is a specialized platform to assist in automated detection, counting, and classification of fish using ARIS (Adaptive Resolution Imaging Sonar) data. ARISFish was used to observe Delta Smelt fish behavior by analyzing the underwater sonar video data for patterns in movement. Delta Smelt release times were noted in the field and associated with each sonar video file. Sonar echograms and videos were used to locate the correct release and observe the Delta Smelt underwater. Swimming behaviors were categorized into four different swimming movements: Running, Milling, Hanging and Backsliding. Running was characterized by a rapid, continuous swimming motion, often in a straight line or with minimal directional changes, prior to leaving the viewing frame. Milling refers to a more erratic, circular, or repetitive pattern prior to leaving the viewing frame. Hanging refers to fish that remain relatively stationary or slowly drifting at a fixed location within the water column prior to leaving the viewing frame. And Backsliding is a behavior where fish swim, or are being pushed, in the opposite direction that their body is aiming prior to leaving the viewing frame. Observed swimming behaviors for the released Delta Smelt were noted as the primary swimming behavior for the entire group, rather than individual fish. Behavior data was entered directly into an Excel file. Behavior data was checked for errors after each day and quality assurance/quality control (QAQC) was conducted post observation collection. QAQC entailed checking that data was entered in all applicable fields, checking for erroneous values, and consulting observer involved. Appropriate changes were then made and noted in the database by the reviewer. Spreadsheets were directly exported from Excel in .xlsx format and then converted to .csv machine-readable file format for publishing. No data was screened from this data release. 2024 Veronica L. Violette USGS - SOUTHWEST REGION Fish Biologist mailing and physical

California Water Science Center,California District Office - Placer Hall

Sacramento CA 95819 916-278-3065 vviolette@usgs.gov Signal processing of raw acoustic data collected using imaging sonar was performed with Echoview software (Echoview, 2014). The software is a specialized platform for the visualization and analysis of hydroacoustic data, enabling the efficient processing of large datasets beyond the capacity of conventional video-based interpretation. The software employs a sequence of filtering operations to enhance acoustic signals while mitigating interference from static objects and background noise (Kang, 2011). Non-stationary acoustic returns are classified as targets within individual camera frames and subsequently transformed into three-dimensional spatial and temporal data, facilitating target tracking. The analytical workflow followed a multi-step process. Initially, positional data from each acoustic camera were referenced in relation to the deployment platform, ensuring spatial alignment of detected targets. Subsequently, acoustic camera data files were imported into Echoview® and converted from raw signal magnitudes to volume backscattering strength (Sv). To eliminate stationary objects, targets were classified as immobile if their mean positional deviation over three consecutive pings remained below a predefined threshold; these stationary targets were subsequently removed from the dataset. Further, static noise was suppressed by applying a sample statistic subtraction operator, which introduced a synthetic ping into the background signal and subtracted it from actual pings, thereby enhancing the signal-to-noise ratio by eliminating returns from inanimate objects and ambient noise sources. Following noise subtraction, image quality was enhanced through a convolution (median) filter algorithm, which utilized the median and maximum values from a data point and its eight adjacent neighboring cells to suppress interference while preserving the structural integrity of the acoustic image. Next, a multibeam target detection operator was implemented to extract multibeam targets from the dataset. These three-dimensional targets, derived from clusters of adjacent data points, were subsequently reduced to point data containing geometric properties of individual fish targets. The extracted targets were then converted from multibeam representations to single-point targets. Upon completion of the filtering and smoothing processes, all single targets and their associated properties were exported as comma-separated values (CSV). These CSV files were then re-imported into Echoview® for further tracking and analysis. The objective of fish tracking was to quantify individual fish movements, counts, and associated behavioral and morphometric parameters (Simmonds & MacLennan, 2005). Summary statistics of detected fish targets, including mean length, movement direction, swimming speed, and position within the sonar beams, were imported into R software (R Core Team, 2014) for data validation and integration with environmental datasets. Data were reviewed to remove invalid records or those lacking measurable morphometric or behavioral attributes. The final target datasets were exported as comma-separated value (CSV) files for further analysis. 2024 Collin Smith USGS - NW-PACIFIC ISLAND REG Fishery Biologist mailing and physical

Columbia River Research Lab Cook WA, Main Building A

Cook WA 98605 509-538-2919 cdsmith@usgs.gov 1.0E-5 1.0E-5 Decimal degrees World Geodetic System 1984 (WGS 84) WGS_1984 6378137.0 298.257223563 Sample Table.csv Comma Separated Value (CSV) file containing data. This data includes environmental conditions, location, sonar settings, experimental release information, and post-processing information for each sonar video that was collected. Producer Defined Video_Number An identifying code for each sonar video file collected which links the fish tracking and behavior data to the sample data. Producer Defined Identifying code for the sonar video file. Water_Year Experimental release water year. Producer Defined 2022 2024 Water Year Event Experimental release event within a release water year. A single release event refers to activities conducted in a given week. Producer Defined 1 6 Date The date (MM/DD/YYYY) the sonar video file was collected. Producer Defined 12/13/2021 01/31/2024 Timing Timing of the Delta Smelt experimental release within a given release event. Producer Defined Pre Before Delta Smelt were released into the wild for that experimental release event. This ranged from a few hours leading up to the release, or up to a couple of days prior to the releases. Producer defined During While Delta Smelt were actively being experimentally released into the wild. Producer defined Between A period of time during Hard Releases (see Sample Table,csv:Type definitions), after batch 1, but before batch 2, where sonar was being collected at the release location and Delta Smelt were not actively being experimentally released into the wild, but the release event was not over yet. Producer defined Post After Delta Smelt were released into the wild for that experimental release event. This ranged from a few hours after Delta Smelt were released, or up to a couple of days after the releases. Producer defined Location Where Delta Smelt were experimentally released and sonar video file was collected Producer Defined Rio Vista Release locations ranged from near the Rio Vista public launch ramp to across from Decker Island. Latitude and Longitudes provided in the Sample Data Table. Producer defined Sacramento Deep Water Shipping Channel Release locations ranged from Channel Marker 51 to Channel Marker 53 within the Sacramento Deep Water Shipping Channel. Latitude and Longitudes provided in the Sample Data Table. Producer defined Montezuma Slough Release locations ranged from at the Belden's Landing bridge to a few hundred feet downstream of the bride in Montezuma Slough. Latitude and Longitudes provided in the Sample Data Table. Producer defined River_Position Where on the river the sonar video file was collected and Delta Smelt were released on. To determine the right and left banks, the data crew faces downstream. Producer Defined Right Bank Facing downstream, the bank to the right is called the right bank. Producer defined Left Bank Facing downstream, the bank to the left is called the left bank. Producer defined Channel Facing downstream, the channel is in the middle of the river. Producer defined Type Delta Smelt were experimentally released using three different methods. Producer Defined Soft Large floating cages were anchored along the shoal at the release location with a lid on it. Delta Smelt were transported via carboys and approximately 3,200 Delta Smelt were placed inside each cage and allowed to acclimate to the environmental conditions for 24 to 48 hours prior to being released into the wild. A total of two cages were released within 100 feet of each other, at once. Cage lids were removed and the cages were lowered down and Delta Smelt were able to exit into the wild out from the top of the cage. Producer defined Hard Delta Smelt were transported via carboys and released directly into the wild over the side of a boat along the shoal, near the channel of the river. Each carboy contained approximately 200 Delta Smelt and fish were released one carboy at a time. For most hard releases there were two batches in a day, with 16 carboys released in a single batch. In a single batch, carboys were released within a couple of minutes from one another. Producer defined Trailer Large quantities of Delta Smelt were transported via a fish hauler to a release location at a public boat launch ramp. Delta Smelt were released directly into the wild, near shore. Producer defined Latitude The latitudinal coordinate that indicates the location of the sonar video file (Datum is WGS 84) Producer Defined 38.10095 38.25625 Longitude The longitudinal coordinate that indicates the location of the sonar video file (Datum is WGS 84) Producer Defined -121.980362 -121.66811 Wind_Speed The wind speed at the time of sampling Producer Defined 20+, big waves heavy whitecaps 20 mph and greater winds resulting in big waves with heavy whitecaps Producer defined 1-5, light ripples 1 to 5 miles per hour (mph) winds resulting in light ripples Producer defined 10-15, some waves, some whitecaps 10 to 15 mph winds resulting in moderate waves with occasional whitecaps Producer defined 5-10, small waves, no whitecaps 5 to 10 mph winds resulting in small waves with no whitecaps Producer defined 0-1, glassy 0 to 1 mph winds resulting in glassy conditions Producer defined 15-20, large waves, frequent whitecaps 15 to 20 mph winds resulting in large waves and frequent whitecaps Producer defined Wind_Direction The direction the wind originates from at the time of sampling. Producer Defined NA No wind detected Producer defined Southeast Wind coming from the Southeast direction Producer defined South Wind coming from the South direction Producer defined West Wind coming from the West direction Producer defined East Wind coming from the East direction Producer defined North Wind coming from the North direction Producer defined Northwest Wind coming from the Northwest direction Producer defined Southwest Wind coming from the Southwest direction Producer defined Northeast Wind coming from the Northeast direction Producer defined Sky The sky conditions at the time of sampling. Producer Defined Overcast The entire sky was cloudy during the sample Producer defined Partly cloudy There were some clouds during the sample Producer defined Clear/Sunny Clear Skies with no clouds during the sample Producer defined Cloudy There were mostly clouds during the sample Producer defined Fog There was low fog during the sample Producer defined Precipitation The type of precipitation at the time of sampling. Producer Defined Steady rain There was steady rain during the sample Producer defined Dry No precipitation during the sample Producer defined Intermittent Rain There was intermittent rain during the sample Producer defined Steady Rain There was steady rain during the sample Producer defined Tide_Phase The tidal phase at the time of sampling Producer Defined Flood The water was moving upstream, into the system, during the sample Producer defined Ebb The water was moving downstream, out of the system, during the sample Producer defined Slack The water was not moving in either direction during the sample Producer defined Camera The location of the sonar and where the sonar was aiming underwater. This identifies what the sonar was aiming to observe during the experimental releases. Producer Defined Predator Sonar camera was mounted off the side of a boat. The sonar was aimed at a downward angle to have the entire water column and riverbed in view. The sonar was positioned just down current of where the release was occurring. Producer defined Smelt Sonar camera was mounted off the side of a boat. The sonar was aimed outward to have the carboy or cage in view during the hard and soft releases. The sonar had a slight downward tilt to eliminate any disturbances from the water surface. This view only viewed just below the surface of the water. The sonar was positioned in line with where the release was occurring, above current of the predator sonar. Producer defined Smelt/Predator In some cases, one sonar was used to observe both just below the surface of the water and the entire water column with the riverbed in view. The sonar would alternate between the two views while mounted off the side of a boat, approximately 0.5 meters under the surface of the water, when sonar units were limited. Producer defined Dock Sonar camera was mounted off a dock. The sonar was aimed at the end of the trailer release tubing where Delta Smelt exited the fish hauler into the wild at a launch ramp. Producer defined Beach Sonar camera was mounted to a frame that rested on the riverbed. The sonar was placed just down current of the release along the beach. Producer defined Start_Time_24Hr The time the sample began (e.g., the moment the sonar started recording) in (UTC-8:00) Pacific Time (US & Canada). Time stamp where HH is the hour, MM is the minute, and SS is the second in 24-hour format. Producer Defined 07:38:50 15:15:00 Video_Duration The total duration in minutes of a single video file that was recorded. Producer Defined 1 51 Camera_Depth The total depth the sonar was lowered to, under the surface of the water, in meters. Producer Defined NULL No Data Producer defined 0.25 3.0 meters Camera_Location Where the sonar was aiming and what part of the water column was in view during the sample. Producer Defined Surface The sonar was just below the surface of the water and only had just below the surface in view Producer defined Bottom The sonar was just below the surface of the water and had the riverbed in view, as well as the rest of the water column Producer defined Cage If the cage was present in this sample Producer Defined Yes The cage was present during this sample Producer defined No The cage was not present during this sample Producer defined Smelt_In_Cages If Delta Smelt were in the cages during this sample. Producer Defined NA Not Applicable given the release type Producer defined No Delta Smelt were not in the cages during this sample Producer defined Yes Delta Smelt were in the cages during this sample Producer defined Camera_Heading The compass heading (in degrees) the sonar was aimed at in this sample. Producer Defined NULL No Data Producer defined 3 355 Degrees Behavior_Processed If Delta Smelt swimming behavior data was post-processed using ARISFish software for this sample Producer Defined No Delta Smelt behavior was not processed for this sample and data is not available Producer defined Yes Delta smelt behavior was processed using ARISFish software for this sample and data is available in the Delta Smelt Behavior Table.csv Producer defined Tracking_Processed If fish tracking data was post-processed using Echoview software for this sample Producer Defined Yes Fish tracking data was processed using Echoview software for this sample and data is available in the Fish Tracking Data table Producer defined No Fish tracking data was not processed for this sample and data is not available Producer defined Delta Smelt Behavior Table.csv Comma Separated Value (CSV) file containing data. This data includes observational Delta Smelt swimming behavior data. Sonar video files that observed Delta Smelt being released were post-processed using Sound Metrics ARISFish software, where Echogram files and the video were viewed in conjunction. Producer Defined Video_Number Numeric code assigned to each sonar video file, which which can be used to like the Sample Table.csv and Fish Tracking Table.csv Producer Defined 71 970 Batch Delta Smelt that were experimentally released into the wild via carboys were released in two batches due to limitations in transportation Producer Defined 1 First batch of the day Producer defined 2 Second batch of the day Producer defined Sequence What order the carboy was released into the wild for a given batch in that day Producer Defined NA Not Applicable due to the release type Producer defined 1 19 Smelt_Quantity The number of cultured Delta Smelt released at a given time for all release types. Producer Defined 200 There were 200 Delta Smelt released at a single time Producer defined 300 There were 300 Delta Smelt released at a single time Producer defined 271 There were 271 Delta Smelt in released at a single time Producer defined 3,046 There were 3,046 Delta Smelt released at single time Producer defined 3,200 There were 3,200 Delta Smelt released at a single time Producer defined 400 There were 400 Delta Smelt released at a single time Producer defined 133 There were 133 Delta Smelt released at a single time Producer defined 3,292 There were 3,292 Delta Smelt released at a single time Producer defined 256 There were 256 Delta Smelt released at a single time Producer defined 258 There were 258 Delta Smelt released at a single time Producer defined 252 There were 252 Delta Smelt released at a single time Producer defined 209 There were 209 Delta Smelt released at a single time Producer defined 206 There were 206 Delta Smelt released at a single time Producer defined 238 There were 238 Delta Smelt released at a single time Producer defined 243 There were 243 Delta Smelt released at a single time Producer defined 201 There were 201 Delta Smelt released at a single time Producer defined 6,240 There were 6,240 Delta Smelt released at a single time Producer defined Release_Time_24Hr The time the Delta Smelt were released into the wild (e.g., the moment the sonar started recording) in (UTC-8:00) Pacific Time (US & Canada) time stamp where HH is the hour and MM is the minute in 24-hour format. Producer Defined 08:50 14:42 Smelt_Primary_Behavior Observational data of Delta Smelt behavior was observed during post-processing using ARISFish software. The primary behavior refers to how the majority of the Delta Smelt were swimming immediately after being released Producer Defined NA Primary behavior unable to be determined due to poor video quality Producer defined Backsliding The swimming behavior refers to a fish swimming in one direction but moving the opposite direction and leaving the viewing frame Producer defined Running The swimming behavior refers to fish swimming and moving in the same direction, quickly leaving the viewing frame Producer defined Hanging The swimming behavior refers to fish remaining relatively stationary in the water, prior to leaving the viewing frame Producer defined Milling The swimming behavior refers to fish swimming in a wandering pattern with no specific direction, prior to leaving the viewing frame Producer defined Smelt_Direction Delta Smelt swimming direction observed during post-processing using ARISFish software immediately after being released. Producer Defined NA Direction unable to be determined due to poor video quality Producer defined All Directions The swimming direction of the fish was no specific direction, and rather the fish same in multiple directions Producer defined With Current/Upstream The swimming direction of the fish was moving in the same direction as the water and upstream Producer defined With Current/Downstream The swimming direction of the fish was moving in the same direction as the water and downstream Producer defined Smelt_Observations Observations made during the post-processing in ARISFish about the quality of the sonar video. Producer Defined NULL No additional observations Producer defined Poor video quality Video quality was too poor to observe certain data that was being collected Producer defined Boat was outside of visible range Distance between the sonar and the release boat was too far to observe the small Delta Smelt that were released, and therefore could not collect behavior data on them Producer defined Fish Tracking Table.csv Comma Separated Value (CSV) file containing data. This data includes individual fish tracking data on both potential Delta Smelt and other ambient fish that swam through the viewing frame. Sonar video files where post-processed using Echoview software. Producer Defined Video_Number Unique identifier for each sonar video file that was collected to associate fish behavior and tracking data back to location, weather, and sonar settings Producer Defined 2 1349 Unique_ID Unique identifier for an individual fish observed Producer Defined DSER_ARIS_1 DSER_ARIS_9998 Num_Targets Number of ping returns per fish Producer Defined 1 1057 Fish_Speed Fish mean four dimensional (4D) unsmoothed swimming speed in meters per second Producer Defined NULL No Data Producer defined 0.00 1.07 meters per second Fish_Direction_Horizontal Direction on fish travel in degrees on a horizontal plane in relation to the sonar. This is not true cardinal direction. Straight out from the sonar is 90 degrees. Producer Defined NULL No Data. Fish direction is unable to be determined due to limited number of detections on an individual fish. Producer defined 0 360 Fish_Heading Calculated fish swimming direction based on the camera heading and fish swimming direction. This is the true cardinal direction the fish was moving. Producer Defined NULL No Data. Fish heading is unable to be determined due to the lack of fish direction. Producer defined 0 360 Time_In_Beam Duration of fish viewing in seconds Producer Defined NULL No Data because only one target was tracked for this individual fish Producer defined 0.1 139.0 Seconds Tortuosity The three dimensional (3D) Tortuosity of a fish's travel path indicates how straight or winding its movement is. The lower the tortuosity value, the straighter and more direct the fish's path, with less overall movement. Producer Defined NULL No Data Producer defined 1 1025 Length_Mean Mean length in centimeters of fish across the total targets collected on an individual fish Producer Defined 2.3 145.2 Centimeters Range_Mean The mean distance from sonar the fish was in meters Producer Defined 1.0 15.2 Meters Range_Min The minimum distance from sonar the fish was in meters Producer Defined 1.0 15.2 Meters Range_Max The maximum distance from sonar the fish was in meters Producer Defined 1.0 15.3 Meters Range_Delta The change in range the fish was from the sonar in meters Producer Defined -2.7 3.0 Meters First_Ping_24Hr The time the fish was first detected at in the sonar file in (UTC-8:00) Pacific Time (US & Canada). Timestamp, where HH represents hours, MM minutes, SS seconds, and MS milliseconds, in 24-hour format (HH:MM:SS.MS). Producer Defined 07:53:04.05 15:23:34.57 All data files are in .CSV format which can be viewed with any text or spreadsheet software. This data release includes data tables with sample information, Delta Smelt swimming behavior data, and individual fish tracking data. Violette, V.L., V.L., Smith, C.D., Young, M.J., and Feyrer, F.V., 2025, Fish Observations During Delta Smelt Experimental Releases Inferred from ARIS Sonar: U.S. Geological Survey data release, https://doi.org/10.5066/P97GF01P GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P97GF01P None 20250513 Veronica L. Violette USGS - SOUTHWEST REGION Fish Biologist mailing and physical

California Water Science Center, California District Office - Placer Hall

Sacramento CA 95819 916-278-3065 vviolette@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999