image description
Sample Design: Boat Electrofishing to Collect Piscivore's Diets
  • ID: 16812
  • State: Finalized
  • Owner: Matt Polacek
  • Collaborator(s): None
  • Spatial Design Category: Simple Random Sample, Non-Stratified
  • Version History: v1.0 Finalized (6/21/2022)

The details of this Sample Design, including all the parameters used to generate it, are included below. Sample designs must belong to a Study Plan.


Predatory fishes will be collected by boat electrofishing along the shoreline in a downstream direction. The electrofishing boat is a custom-built 2016, 20-foot Smith-Root Electrofishing Boat powered by a 115-horsepower outboard (propeller) engine. Electrofisher settings will be pulsed direct current (DC) at 60 pulses per second, 40% power, and low voltage range (50-500 V). Electrofisher output will be generally 2-4 amperes and adjusted to achieve fish galvanotaxis (narcosis). The crew will consist of a certified boat operator and two netters. Sampling will occur one hour after sunset to one hour before sunrise. A similar level of effort (e.g., electrofishing seconds, distance (m)) will be used at each site within each stratum. 

Temporal stratification of sites during sampling will provide data representative of the period of greatest overlap between non-native predator fishes and rearing/migrating juvenile salmonids.  Two sampling times will occur to collect predator fish diet contents. The first will occur during the first half of May to represent age-1 chinook, sockeye, Coho, and steelhead smolt (e.g. yearlings). The second will occur in early to mid-June to represent age-0 Chinook smolt outmigration (subyearling).

Stomach contents will be collected from WAL and SMB using gastric lavage.  Less common non-native fishes (e.g. Largemouth Bass, Yellow Perch, Black Crappie) will be collected and evaluated for predatory impact on salmonids. Fish will be measured, weighed, scanned for PIT tags, and stomachs/diet contents will be stored in individually labeled Whirl-Pak bags. NPM and CC will be measured, weighed, and euthanized (Close et al. 1997) and stomachs will be dissected and placed into individually labeled Whirl-Pak bags. The entire digestive tract will be removed from NPM. Samples will be preserved with 95% ethanol, stored in a cooler with dry ice, and transferred to a lab freezer until analysis. Otoliths will be removed from a sub-sample of SMB and WAL >150 mm and scales from SMB and WAL <150 mm, and opercles from NPM for aging. Aging structures will be analyzed by the WDFW aging lab.

Start Year


End Year

Study Plan

Piscivore Diet Collection and Analysis v1.0

Data Repositories





Area of Inference


AOI Notes


Sample Sites
These are the unique sites that are participating in this sample design over the time period covered by the design.

Map of Sites


Sampling Schedule
This section describes which sites are scheduled to be sampled in any given year, and (if applicable) the panel and stratum that the sample site belongs to.

Plan Description


End User License Agreement

All visitors to may read content without creating a user account. To add content and participate in collaboration features, users must create an account. Account holders must provide their name and email address, which will be viewable by anyone visiting the site.

Privacy Act Statement


Relevant acts include the Organic Act, 43 U.S.C. 31 et seq., 1879; Fish and Wildlife Coordination Act, 1934; Fish and Wildlife Act, 1956; Migratory Bird Treaty Act, 1918; Migratory Bird Conservation Act, 1900; Federal Land Policy and Management Act, 1976; Fish and Wildlife Improvement Act, 1978; Endangered Species Act, 1973; Marine Mammal Protection Act, 1972; Great Lakes Fishery Act, 1956; Nonindigenous Aquatic Nuisance Prevention and Control Act, 1990; Water Resources Development Act, 1990; and other authorizations conveyed to the U.S. Geological Survey.

Principal Purpose provides a structured system to document, store, manage and share methods, protocols, sample designs, study plans and sample locations related to natural resource monitoring and research.

Routine Uses

Used to document and share the who, what, where, when and how of natural resources monitoring and research. Users who wish to provide content, edit content and use the collaboration features of the site must create an account. Account holders must provide their name and email address, which will be viewable by anyone visiting the site. staff may use email addresses to periodically communicate development updates, bug fixes and content to participants and to assist with completion of content, if needed. The Community feature of supports User Profiles, which allows all site visitors to view name, email and each users’ content. Name and email of participants entering information is published via application programing interfaces (API) and shared with Sitka Technology Group (vendor contracted for site development).

For all site visitors, the following information is collected:

  • The name of the domain from which you entered our website (for example, "")
  • IP Address (an IP address is a number that is automatically assigned to your computer whenever you are connected to the web)
  • The type of browser and operating system used to access our website
  • The date and time you access our website
  • The pages within our website that you visit
  • If you linked to our website from another website, the address of the website
  • This website uses session cookies. They provide enhanced navigation through the website.

We use this information to measure the number of visitors to the different sections of our website and to help make our website more useful to visitors. We do not track or record information about individuals and their visits. This information is not shared with anyone beyond the support staff for this website, except when required by Law Enforcement investigation. This information is not sold for commercial marketing purposes.

Disclosure is Voluntary

If the individual does not furnish the information requested, there will be no adverse consequences. However, if you do not provide your first and last name and email address you will not be able to enter content into

Paperwork Reduction Act Statement

The Paperwork Reduction Act of 1995 (44 U.S.C 3501 et.seq.) requires us to inform you that the information is being collected to supplement natural resource monitoring metadata, to promote publicly accessible documentation of monitoring projects, and support coordination and integration of monitoring efforts. Use of the tools is voluntary. Use of this website is estimated to be about 1 hour per response. A Federal agency may not conduct or sponsor, and a person is not required to respond to a collection of information unless it displays a currently valid OMB control number. Comments regarding this collection of information should be directed to: Bureau Clearance officer, U.S. Geological Survey, . OMB Control Number 1090-0011 Expires 10/31/2021.