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Anadromous cataloging and fish inventory in select drainages of the Upper Tanana and Yukon Rivers 2019

Citation

Cathcart, Charles (2021), Anadromous cataloging and fish inventory in select drainages of the Upper Tanana and Yukon Rivers 2019, Dryad, Dataset, https://doi.org/10.5061/dryad.jm63xsj98

Abstract

During the summer of 2019, Alaska Department of Fish and Game Division of Sport Fish staff conducted a rapid systematic inventory of anadromous fish distribution and associated aquatic and riparian habitat in select drainages of the upper Yukon River and Tanana River. Target streams will be selected to fill gaps in coverage of the State of Alaska's Catalog of Waters Important for the Spawning, Rearing or Migration of Anadromous Fishes (AWC) for freshwater habitats expected to support anadromous fish populations likely to be impacted by human activities. Two crews sampled standardized target stream reaches using electrofishers with sufficient effort to collect all species (perhaps with the exception of rare species) of the extant fish community. At each sampling site, crews documented standard aquatic and riparian habitat characteristics. For each water body in which anadromous fish are observed, nominations to the AWC were submitted. One hundred sites were surveyed during this study period, a slightly smaller number than what was expected due to long term drying patterns in the region that led to farther travel times in addition to flooding events that happened after heavy rains.

Methods

Following ADF&G's AFFI protocols, two crews, each with two members, will simultaneously sample fish communities in selected study stream reaches for approximately 20 days during the summer of 2019. Target survey sites will include wadeable headwater streams sampled with a backpack electrofisher and un-wadeable streams (including mainstem rivers) sampled with a raft mounted electrofisher. Two helicopters will provide access to the stream study sites for headwater and cataraft crews. Sites within the study area that have the highest potential for habitat degradation will be identified through consultation with the ADF&G Division of Habitat and will be given a higher sampling priority.

The number of headwater streams in the study area will exceed the project’s limited sampling effort capacity; therefore, a subset of mapped streams, comprising the longest stream segments not currently listed in the AWC, will be selected as target streams. The headwater team will sample approximately six to eight headwater streams per day and the raft team will float and sample one un-wadeable stream per day, including a reach from all mainstem rivers in the study area. 

Sampling methods

At selected streams, the fish community will be sampled with standardized methods and effort according to AFFI protocols. Fish will typically be collected by single-pass electrofishing (other non-lethal gear types such as beach seines, angling, or minnow traps may be deployed if conditions prohibit safe or effective electrofishing). Electrofishing is the principal fish collection gear because it is recognized as the most comprehensive and effective method for collecting fish in lotic systems. 

At all target streams, a length of stream (referred to as a reach) standardized by stream width (i.e., 40 or 120 wetted-channel-widths in wadeable and un-wadeable target streams, respectively, or, in large rivers, the maximum length of stream that can be sampled in one day) was sampled to include all aquatic habitat types within that reach. Collected fish will be identified to species, tallied, measure for fork length, and examined for external abnormalities. Additionally, standard water chemistry, channel morphology, and riparian habitat parameters will be recorded at each sample site. To enhance data quality and completeness and data entry efficiency, all collected data will be entered each day into an integrated database installed on a notebook computer.

Usage Notes

For alternative visualization of the data, see the interactive mapping feature at:

http://www.adfg.alaska.gov/index.cfm?adfg=ffinventory.interactive

Funding

Alaska Sustainable Salmon Fund, Award: AKSSF44375