Geology topics

William Hurst

Publications and source records attributed to William Hurst.

3 recordsLinked to original sources

USGS2018

Passage survival of juvenile steelhead, coho salmon, and Chinook salmon in Lake Scanewa and at Cowlitz Falls Dam, Cowlitz River, Washington, 2010–16

A multi-year evaluation was conducted during 2010–16 to evaluate passage survival of juvenile steelhead ( Oncorhynchus mykiss ), Chinook salmon ( O. tshawytscha ), and coho salmon ( O. kisutch ) in Lake Scanewa, and at Cowlitz Falls Dam in the upper Cowlitz River Basin, Washington. Reservoir passage survival was evaluated in 2010, 2011, and 2016, and included the tagging and release of 1,127 juvenile salmonids. Tagged fish were released directly into the Cowlitz and Cispus Rivers, 22.3 and 8.9 km, respectively, upstream of the reservoir, and were monitored as they moved downstream into, and through the reservoir. A single release-recapture survival model was used to analyze detection records and estimate reservoir passage survival, which was defined as successful passage from reservoir entry to arrival at Cowlitz Falls Dam. Tagged fish generally moved quickly downstream of the release sites and, on average, arrived in the dam forebay within 2 d of release. Median travel time from release to first detection at the dam ranged from 0.23 to 0.96 d for juvenile steelhead, from 0.15 to 1.11 d for juvenile coho salmon, and from 0.18 to 1.89 d for juvenile Chinook salmon. Minimum reservoir passage survival probabilities were 0.960 for steelhead, 0.855 for coho salmon and 0.900 for Chinook salmon. Dam passage survival was evaluated at the pilot-study level during 2013–16 and included the tagging and release of 2,512 juvenile salmonids. Juvenile Chinook salmon were evaluated during 2013–14, and juvenile steelhead and coho salmon were evaluated during 2015–16. A paired-release study design was used that included release sites located upstream and downstream of Cowlitz Falls Dam. The downstream release site was positioned at the downstream margin of the dam’s tailrace, which allowed dam passage survival to be measured in a manner that included mortality that occurred in the passage route and in the dam tailrace. More than one-half of the tagged Chinook salmon (52 percent) released upstream of Cowlitz Falls Dam moved downstream and passed the project; the remaining fish either remained upstream of the dam (37 percent) or were collected (11 percent). In 2015 and 2016, collection efficiencies at Cowlitz Falls Dam were abnormally high for juvenile steelhead and coho salmon, which resulted in few fish passing the dam. Seven percent of the tagged steelhead (40 fish) and 4 percent of the tagged coho salmon (18 fish) released upstream of the dam eventually passed the project, but these low numbers of fish precluded the estimation of meaningful survival estimates. Dam passage survival probability estimates for juvenile Chinook salmon were 0.828 in 2013 and 0.861 in 2014, lower than previously reported for turbine-specific passage Cowlitz Falls Dam.

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USGS2016

Feeding ecology of non-native Siberian prawns, Palaemon modestus (Heller, 1862) (Decapoda, Palaemonidae), in the lower Snake River, Washington, U.S.A.

We used both stomach content and stable isotope analyses to describe the feeding ecology of Siberian prawns Palaemon modestus (Heller, 1862), a non-native caridean shrimp that is a relatively recent invader of the lower Snake River. Based on identifiable prey in stomachs, the opossum shrimp Neomysis mercedis Holmes, 1896 comprised up to 34-55% (by weight) of diets of juvenile to adult P. modestus , which showed little seasonal variation. Other predominant items/taxa consumed included detritus, amphipods, dipteran larvae, and oligochaetes. Stable isotope analysis supported diet results and also suggested that much of the food consumed by P. modestus that was not identifiable came from benthic sources — predominantly invertebrates of lower trophic levels and detritus. Palaemon modestus consumption of N. mercedis may pose a competitive threat to juvenile salmon and resident fishes which also rely heavily on that prey.

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USGS2015

Evaluation of two juvenile salmon collection devices at Cowlitz Falls Dam, Washington, 2014

Collection of juvenile salmon at Cowlitz Falls Dam is a critical part of the effort to restore salmon in the upper Cowlitz River, Washington. Many of the fish that are not collected pass downstream and enter Riffe Lake, become landlocked, and are lost to the anadromous population. In addition to this loss, the juvenile fish collection system at Cowlitz Falls Dam, which originally consisted of four collection flumes, has failed to achieve annual collection goals since it began operating in 1996. In the years since, the collection flumes have been modified and prototype collection devices have been developed and tested, but these efforts have not substantially increased juvenile fish collection. Studies have shown that juvenile steelhead ( Oncorhynchus mykiss ), coho salmon ( Oncorhynchus kisutch ), and Chinook salmon ( Oncorhynchus tshawytscha ) tend to come close to the entrances of the collection system, but many of these fish fail to enter and eventually pass the dam through turbines or spillways. Tacoma Power developed a prototype weir box in 2009 to increase capture rates of juvenile salmon at the collection entrances. The device was evaluated with radio-tagged coho salmon (318 fish) and Chinook salmon (317 fish), and was found to have a high retention rate; 93 percent of the coho salmon, and 91 percent of the Chinook salmon that entered the device were retained and collected. However, because of safety concerns at the dam, the weir box could not be deployed near a spillway gate where the prototype was tested, so the device was altered and re-deployed at a different location where it was evaluated during 2013. During that year, discovery efficiency (number of fish detected at the entrance divided by the number of fish detected in the forebay) was 98 percent for tagged steelhead and 83 percent for tagged coho salmon. However, none of the steelhead and only 5 percent of the coho salmon entered and were collected through the weir box. These results indicated that the device was not a promising collection alternative during spring months when steelhead and coho salmon are passing the dam. However, collection conditions change during summer months when juvenile Chinook salmon are passing, so the device also was evaluated during summer 2014. In an attempt to improve overall collection efficiency, Tacoma Power developed and tested a new device in 2014, called the Upper Riffe Lake Collector (URLC). The URLC was a floating device designed to collect fish as they moved downstream after passing through turbines at Cowlitz Falls Dam. The design of the URLC included a pontoon barge that supported a large net structure designed to funnel fish into a live box where they could be removed and transported downstream of dams on the Cowlitz River.

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