Data Package Metadata   View Summary

1.) Data Collection methods:

A single tow of the net is conducted at each of 44 sampling stations. Environmental conditions data, including tide, turbidity, surface and bottom conductivity, water temperature, and secchi depth, are collected at each station at the time of sampling. At the end of each tow, net contents are washed into a cod-end jar, the jar is removed, and its contents preserved in 10% formalin for identification in the lab. A General Oceanics flowmeter is mounted across the net's mouth to estimate the water volume filtered. The distinctively labeled sample jars are taken to the laboratory at the California Department of Fish and Wildlife's Bay Delta Region, Stockton. The complete contents are sorted and any larval fish present are identified and counted. All fish are identified to species or lowest possible taxon. The first 50 fish of each species from each tow are randomly selected and measured (FL) to the nearest millimeter. All Longfin smelt are measured regardless of catch size.

2.) Link to blank datasheet:

Available upon request (see data contact information)

3.) Instrument and Equipment Specifications, including QAQC methods and frequency:

The IEP-SLS uses a cone shaped net 3.35 meters in length with a mouth area of 0.37 m2. The net itself is composed of 505 microm NitexR and is mounted on a fixed metal tube frame with skis. The mesh was altered prior to the 2014 season to 500 microm NitexR, when new nets were purchased and the original mesh was no longer available (see 2014 changes below). These new nets were incorporated as old nets became unusable. The net is connected to the frame by a canvas mouth. Nets are checked for tears after each tow. The YSI Model 30 is used to measure water temperature and electrical conductivity. The probe is rinsed between samples by storing it in a bottle of distilled water that is discarded at the end of the day. YSI units are calibrated using commercially available conductivity standards annually before the beginning of each survey season. Hach 2100P turbidity meters are used to measure turbidity in nephelometric turbidity units (NTUs). Turbidity meters are calibrated annually with commercially available standards designed specifically for the model before each field season. Secchi discs are black and white discs that measure water clarity by measuring the depth of disappearance from the water's surface, or the distance light can penetrate. Secchi discs are mounted onto rigid meter sticks, with a maximum depth of 200cm. Measurements are taken in the shade, with no sunglasses on, and are done by the same person the entire day for consistency.

4.) Analysis Methods and SOPs:

Water volume sampled in each tow is calculated using data collected by a flowmeter mounted to the net. The difference in flowmeter counts is calculated by subtracting the flowmeter reading when the net is put into the water from the flowmeter reading when the net is taken out of the water. This value is then multiplied by a factory calibration factor to convert the reading into a number of meters of flow. This is multiplied by the area of the net to estimate the volume of water sampled in each tow.

5.) Project History:

2009 – Project start. Five biweekly delta-wide (35 stations) surveys conducted from early January to early March

2010 – Temporal extension of sampling; 6 biweekly delta-wide (35 stations) surveys conducted from early January to late March. Implementation of the use of a Hach Model # 2100P Turbidimeter as Standard Operating Procedure to record turbidity in NTU's. Recorded Latitude and Longitude on datasheets, but not entered into database.

2011 – Latitude and Longitude recorded in database. Yolk sac and oil globule presence noted in data.

2012 - Sixth survey added.

2014 – Spatial extension of sampling into Napa River as part of an agreement with the State Water Contractors (stations 340, 342, 343, 344, 345, 346, 347, 348, and 349). Database was revised by Tuongvan Nguyen at ITB as part of the Bay Delta Application Hosting to move public facing data onto secure Tier 3 server. Data is now entered into SLS_Local.mdb, housed in SLS_Query.mdb (local server), and appended to the tier 3 server before uploading to webpage. New nets were incorpoated (manufactured on 5/10/2013 by Lodi Tent and Awning) with a different Nitex Mesh purchased from Sefar (500 micron, 47% open space. Part # 06-500/47).

2015 – Factory k value (0.026873027) used in MeterCorrections table. Flowmeters were not calibrated at UC Davis due to machinery malfunction. Facility is awaiting repair.

2016 – Continued using factory k value for MeterCorrections. Flowmeters were sent to General Oceanic for refurbishing prior to field season.

2017 - Continued using factory k value for MeterCorrections. Flowmeters were sent to General Oceanic for refurbishing prior to field season.

2018- Continued using factory k value for MeterCorrections.

2019- Continued using factory k value for MeterCorrections. Ceased sampling stations within the Napa River (stations 340, 342, 343, 344, 345, 346, 347, 348, and 349).

6.) QA/QC

Methods: After each tow, the field lead verifies that the flowmeter count is within the appropriate range, and if not, a re-tow is required. If there is an obvious reason that the flow meter was out of range, (e.g. weeds caught in the net or on the flowmeter), it is recorded as the reason for a re-tow in the comments section of the datasheet. The net can clog during algal blooms, jellyfish blooms, or heavy debris loads. If material is overfilling the cod end jar, the tow time is reduced to 5 minutes or 2.5 minutes and the appropriate tow schedule is followed. The acceptable flowmeter check range is reduced accordingly. If a 2.5 minute tow is performed and material like algae, jellyfish, or peat is still overfilling the cod end, that tow at that entire station is dropped. For consistency, all larval and juvenile fish are preserved and processed in the laboratory. Fish are separated from debris and other organisms present in a sample in a process referred to as sorting. A portion of samples are randomly selected after sorting for a quality control check (QC). The level of experience and the documented error rate of the sorter determine the proportion of sorted samples that is QCed. If a QC is required, the QC'er will go through the sample looking for any missed fish. Fish identification involves a first ID person and a QC by a fish ID specialist to confirm all species. Following a QC frequency protocol based on the experience of the identifier, fish identifiers will progressively have fewer and fewer samples QC'd until they are considered a fish ID specialist. Samples for identification QC are randomly selected. The larval fish ID specialist will confirm identification and counts for all fish in the sample. For all samples (QC required or not), all ESA fish and any questionable fish must undergo a second ID.

Data: All computer data entry into the local database undergoes two rounds of ‘line by line' checks, wherein all fields are checked against the original datasheets for fidelity. At the end of the survey field season, once all of the fish samples have been processed in the laboratory and data entry is complete, the environmental and fish data is ‘finalized' such that it is clean for analysis and available for public consumption. The first step in this process is to conduct final line-by-lines. Each survey gets two complete line-by-lines (in addition to the two line-by-lines conducted upon entry). Once the end of season line-by-line is complete a project lead will run a series of database queries called ‘Edit' queries. These queries catch outliers and other erroneous environmental and catch data. Not all data is changed because it is an outlier (outside of 2 standard deviations is the criteria for most queries). In most cases, outliers are real data. These queries are to alert the project lead of potential erroneous data, and care is taken to edit only data that truly needs to be edited.

7.) Contractor Information: N/A

8.) External Review Process: N/A

9.) Methods References: N/A