Archive for Vaki Riverwatcher

Chinook salmon escapement preview

American River Chinook salmon

Across the West Coast, fall-run Chinook salmon migration is wrapping up and abundance estimates are being calculated. Most salmon abundance counts are calculated using carcass surveys to approximate the number of salmon in a watershed, but the disadvantage of this method is that escapement estimates are not available until after the migration period is complete. There are a few tributaries, however, that have adopted different techniques, such as video monitoring or the use of a Riverwatcher for enumerating fall-run Chinook salmon, that allow for real-time calculations. Using this information can provide more rapid insight into what salmon abundance looks like in 2013.

In the Sacramento River Basin, the U.S. Fish and Wildlife Service monitors fall-run Chinook salmon on Battle Creek with the use of video, and has the ability to enumerate Chinook salmon escapement on a semi-real-time basis. The 2013 Sacramento River Fall-run Chinook (SRFC) counts were predicted to be similar to those in 2012, and if Battle Creek is any indication, then 2013 was another good year. Through November 29, 93,527 Chinook salmon were counted migrating past the video station, which is down slightly from the 100,235 salmon observed in 2012.

The San Joaquin Basin could provide additional insight to the SRFC count because it is part of the California Delta and its trends are similar to SRFC stocks. East Bay Municipal Utilities District operates a video station in the fish ladder at Woodbridge Dam on the Mokelumne River. Thus far, 12,108 Chinook salmon have been counted passing upstream, similar to the 12,083 observed in 2012 prior to January 1. Farther south, the Tri-Dam Project funds the use of a Riverwatcher on the Stanislaus River and Turlock Irrigation District funds a Riverwatcher on the Tuolumne River. In 2013, there have been 5,391 Chinook salmon counted by the Riverwatcher on the Stanislaus River as of December 12, which is down from last year’s total of 7,132 salmon recorded prior to January 1. In contrast, 3,587 Chinook salmon have been counted in the Tuolumne River as of December 12, compared to 2,181 counted in 2012.

The Russian River is a coastal tributary that terminates north of the San Francisco Bay, and prior to the turn of the century not much was known about the abundance of Chinook salmon in the area. In 2012, escapement on the Russian River was the largest on record at 6,697; however, as of December 15 this year, only 2,716 Chinook salmon have been recorded at the Mirabel Inflatable Dam during the 2013 monitoring season.

By far the biggest surprise this year has come from the Columbia River at Bonneville Dam, where Chinook salmon counts have been collected since 1938. Prior to 2013, the largest adult fall-run Chinook salmon count at Bonneville occurred in 2003, and numbered 610,075 salmon. But this year, that number has been dwarfed by the 952,944 Fall-run Chinook salmon that were counted passing upstream of Bonneville Dam.

A real-time calculation of fall-run Chinook salmon escapement is helpful for monitoring populations during the season. Preseason forecasts provided by the Pacific Fishery Management Council are the best management tool available today, but inaccuracies do occur in these estimates. Having the ability identify such variations will allow for in-season modifications to regulations. For example, if counts are unexpectedly low, then harvest numbers can be decreased, while in the event of an unexpected abundance, regulations could be relaxed to allow for more take by recreational anglers. It’s important to have up-to-date information to adjust regulations and minimize harvest impacts on salmon populations.

This post featured in our weekly newsletter, the Fish Report. You can subscribe to the Fish Report here.

Fish passage connections

nal Fish Passage conference

International Fish Passage conference

A big thank you to everyone who came out to visit FISHBIO and VAKI at the International Conference on Engineering & Ecohydrology for Fish Passage at Oregon State University last week. The conference was a great mix of international professionals interested in fish passage, and we had many stimulating discussions with the folks who stopped by our booth. We enjoyed the opportunity to meet engineers, biologists, managers, and public relations professionals from power companies like Bonneville Power, Idaho Power, Portland General Electric, Eugene Water & Electric, Alliant Energy, Duke Energy, and Pacificorp Energy. Many organizations in attendance displayed a wide array of products and services, and we were happy to include the VAKI Riverwatcher among them. The conference was a great opportunity for all to learn about fish passage engineering and restoration projects, both locally in regions like the Columbia Basin, and internationally in areas such as the Four Major Rivers Restoration Project in South Korea. We look forward to seeing what new ideas, collaborations, and projects develop from these interactions.  


The one that got away…

A handy feature of the VAKI Riverwatcher system is that it allows us to record video clips of each fish that passes through our fish counting weirs. In addition to identifying the fish species, length, and passage date when we review the video, we also document the condition of each fish. We look for abrasions, lacerations, fungal infections, lamprey scars, hook scars—and in this case the actual hook! In this video you can see the shiny fishing lure dangling from a Chinook salmon’s dorsal fin. The angler is probably disappointed that he or she foul-hooked this salmon and lost not only the catch, but the lure to boot—although it does make for a flashy fish accessory.

Seminar success!

If you’re having trouble viewing the presentation, you can also download it.

FISHBIO and VAKI Aquaculture Systems conducted a seminar this week in California to introduce fisheries biologists to the Riverwatcher fish monitoring system. We were pleased with the turnout and the interest in the Riverwatcher’s capabilities. Magnús Þór Ásgeirsson from the VAKI Corporation in Iceland provided a fantastic overview of the evolution of the system and demonstrated the operation of the equipment and software. Ryan Cuthbert from FISHBIO shared his 10 years of experience using Riverwatchers to enumerate instream fish migrations and demonstrated various data analysis possibilities. The seminar also included a fieldtrip to the Tuolumne River fish counting weir to see the system in action during the fall-run Chinook salmon migration. Participants showed great interest in the integration of the Riverwatcher system with resistance board weirs and other fish ways. A good example of this was our recent post on the integrated Riverwatcher/PIT tag antenna used by Casitas Municipal Water District to monitor steelhead in Southern California.

Moonwalk passage

Adding a little humor to an otherwise routine task, this crewmember shows off his dance moves after cleaning algae from the viewing window of a fish counting weir. Using high tech electronic fish counting systems, like the Vaki Riverwatcher, to record fish passage provides highly accurate results; but like most things in life (here comes the cliché), you only get out what you put into it. Field technicians regularly visit our fish counting weirs to clean the camera lens, lights and glass that monitor the fish passage chute (or in this case the dance floor).

New frontiers

The 141st annual meeting of the American Fisheries Society is currently underway in Seattle, Washington and the theme for the event is “New Frontiers in Fisheries Management and Ecology: Leading the Way in a Changing World.” This year is expected to surpass all others, with an estimated 4,000 in attendance. Fisheries biologists from FISHBIO, along with others from around the world, are presenting their research findings and sharing ideas for new and innovative technologies. For example, this year we are demonstrating the VAKI Riverwatcher in the Trade Show. By fabricating a mechanical carousel that passes a fiberglass fish though the Riverwatcher, we can show observers first-hand how the device detects passing fish and records data.

DIY Riverwatcher

We’re always looking for better ways to showcase the easy setup and use of the VAKI Riverwatcher fish counter. We’ve had great success over our 8 years of using it, and get asked a lot of questions about installation and how it works. So, it only made sense to put our technicians to the task of fabricating a portable display in the FABLAB to demo it.

Because the system is made up of 4 key components, they’re easy to put together and easily adaptable to various applications, such as resistance board weirs, fish traps, fish ladders, fykes, flumes and many others. Our own Scott Wucherer demonstrates how the system works.

2010 CV Fall Chinook escapement estimates only tell half the story

chinook salmon carcass surveyPreliminary estimates of adult fall-run Chinook salmon escapement (that is, the number of adults returning to spawn) in the Central Valley in 2010 have been posted in the “GrandTab” by the California Department of Fish and Game. A summary table is provided below.

The number of Sacramento River fall-run Chinook salmon (SRFC) is 152,831 and for the San Joaquin River basin is 10,350. Although numbers are up from previous years, SRFC numbers are still below the 2010 conservation objective of 180,000 recommended by the Pacific Fishery Management Council, and adult returns are likely to be lower in 2011 considering that the number of parents and associated juvenile production contributing to adult returns in 2011 will be substantially less than 2010. In fact, the 2011 SRFC escapement will be comprised of adults produced from the three lowest adult return years on record for SRFC – 2007, 2008, and 2009. As such, the parental stock (brood years 2007, 2008, and 2009) for adult fish returning to spawn in 2011 is 212,089, which is 52.3% less than the parental stock abundance for 2010 escapement.2010 fall-run chinook salmon escapement tableAdditionally, abundance is only part of the story because the “GrandTab” only provides the numbers of fish observed in each location, not their origins. That is, the numbers reported for “Hatcheries” in the “GrandTab” are the number of salmon entering the hatcheries to spawn (which may consist of both hatchery-origin and natural-origin fish) and the numbers reported for “In-river” are the estimated number of salmon spawning in the rivers (which also may consist of both hatchery-origin and natural-origin fish). In 2010, a considerable portion of adult in-river returns was likely composed of hatchery-origin salmon, particularly in San Joaquin Basin tributaries where increased numbers of ad-clipped fish were observed at the Stanislaus River weir (24.7% as of 12/6/10) and the Tuolumne River weir (29.0% as of 11/30/10) (See FISHBIO Update 2 for more details). Most ad-clipped fish are of hatchery origin. Since neither of these two tributaries have hatcheries and no ad-clipped fish have been released into them since 2006, the observed numbers of marked fish indicates that a tremendous amount of straying has occurred, and that hatchery fish probably make up a much larger percentage of CV escapement than previously thought.

High straying rates of hatchery-origin salmon is generally attributed to Central Valley hatchery practices and straying, in part, has led to the genetic homogenization of Central Valley fall-run Chinook salmon populations. In 2005, a genetic study of Central Valley Chinook salmon (Williamson and May 2005) did not observe genetic separation of any natural or hatchery Central Valley populations, even between populations of the Sacramento and San Joaquin Basin, which is in contrast to other major Pacific salmon regions (Alaska, British Columbia, and the Pacific Northwest), where basin scale genetic diversity has been demonstrated. A decrease in genetic diversity may result in reduced fitness and lower productivity of natural populations, leading Central Valley fall-run Chinook salmon to be more susceptible to environmental stressors.

Photo source: FISHBIO

Fish counting weir: chutes and liveboxes

This post is the last in a “how to” series on the basic components of building a fish counting weir. A weir can have many uses, in some cases this fence-like structure might be built to exclude fish from a certain location, but the majority of weirs are used to enumerate migrating species or to trap fish in order to collect biological data or brood stock for a hatchery programFor fish counting weirs, an opening must be created in order for fish to be counted as they pass through. This can be achieved by removing one or more resistance weir panels, but is better accomplished by modifying a panel to create a passing chute. Fish migrating upriver encounter the weir and move sideways from bank to bank until they locate the opening. For salmonid monitoring, the passing chute is located near the thalweg where there is ample flow for fish to cue in on. Passing chutes can be fitted with electronic monitoring equipment (VAKI Riverwatcher, Video recorder, PIT tag antenna, etc.) and/or a livebox fish trap.Fish traps can be as large and sophisticated, or as small and simplified as need for a particular application. A livebox fish tap typically consists of a rectangular cage fabricated from aluminum or galvanized steel to prevent corrosion. One or more fykes are located at the entrance to help guide the fish into the box, and to reduce the likelihood of fish escaping or moving back downstream. Liveboxes may also include a crowder gate that can guide trapped fish to one side of the trap or facilitate removal. Resistance board weirs are gaining recognition as a respected device in fisheries management and we hope that after reading our posts you have better understanding of the process of weir fabrication.

See the other posts from this how to series:
Fish counting weir: how to series
Fish counting weir: substrate rail
Fish counting weir: resistance weir panels
Fish counting weir: rigid weir and bulkhead

Photo source: FISHBIO

Fish counting weir: rigid weir and bulkhead



Resistance board weir panels are designed for use in the main river channel and adjust to changing flow and debris conditions, but they are not intended for sloped river banks. Instead, rigid weir panels are used on either side of the resistance panels to extend the weir out to the bank. Rigid panels are simply galvanized steel pipes welded to iron cross members, held in place by A-frame supports. We usually make the panels 3 ft. wide and 5 to 10 ft. tall, depending on the expected range of channel depths. Large vertical panels (5 ft. x 20 ft.) called bulkheads serve as an interface between the stationary and movable parts of the weir, moving up and down with the resistance board panels. Bulkheads consist of a welded aluminum frame with PVC conduit pickets spaced 2 in. apart, and are fastened to long stakes driven into the substrate.


Photo source: FISHBIO