Record Numbers of Salmon Return to Mokelumne River Fish Hatchery

The Mokelumne River Hatchery in Clements is hosting the return of big numbers of fall-run Chinook salmon from the ocean this autumn. The run is behind the numbers seen last year at this time, but this run is still going to be one of the top three recorded on the river.

The count over Woodbridge Dam on the Mokelumne to date is 16,300 salmon, including 5,654 jacks, according to William Smith, hatchery manager. The final numbers of salmon going over the dam won’t be available until January 2019.

A record number of fall-run Chinook salmon, 19,954, went over Woodbridge Dam in the fall of 2017, the highest number since 1940. Early dam counts indicated an increase over last year’s run, but the numbers since then have fallen around 1600 fish behind those of last year.

More fish are on the way, as evidenced by continuing reports of salmon being caught in the Mokelumne below Interstate Five, the South Fork Mokelumne and Hog and Beaver Sloughs as the salmon season neared its end on December 16.

“One of our hatchery employees, Jake Aucelluzzo, recently landed a bright 14 lb. salmon while fishing a Rat-L-Trap for striped bass in Hog Slough,” said Smith.

This fall produced superb fishing in the lower Mokelumne River, South Fork Mokelumne and sloughs adjacent to the river. The anglers caught the fish while both trolling with spinners and plugs and jigging with a variety of spoons.

For example, Kristin Lanzarone-Scribner of Sacramento and Eric Webb had a great day in October when they landed four hefty salmon while jigging in the Mokelumne. It was Kristin’s first ever time salmon fishing – and she went home with her two fish limit!

When I went to the hatchery on November 29 to take photos, the river and hatchery were plugged with salmon ready to spawn.

The steelhead numbers reported to date are behind those of last season’s record run., but still robust. To date, the hatchery has counted 116 adult steelhead and 227 half pounders (juveniles). That compares to 406 adults and 34 juveniles last season to date.

A record for the number of steelhead returning to the Mokelumne River Fish Hatchery in one season was set earlier this year. The hatchery trapped 530 adults and 638 juveniles, a total of 1,168 fish. That compares to 719 adults and 402 juveniles the previous season, a total of 1,121 fish.

This is quite a turnaround for the river, since no steelhead came back to the hatchery, located on the river right below Camanche Dam, for 10 years from 1976 through 1986. Again in 1998-1999, no adult steelhead returned to the facility.

That doesn’t mean that there weren’t any rainbows in the river during these years. The river hosted a popular resident trout fishery for fly, bait and lure anglers, but relatively few of the 100,000 steelhead yearlings released every year went to saltwater and returned.

The river, before the listing of the Central Valley steelhead under the Endangered Species Act (ESA), was managed as a catchable trout fishery, rather than as a wild steelhead or trout river. The CDFW regularly stocked the river with catchable size steelhead in the 10 to 15-inch range, hatched from steelhead eggs obtained from the Mokelumne and Nimbus Fish hatcheries.

There are many factors behind the record salmon and steelhead runs in recent years on the Mokelumne. “Strong returns confirm the health of the Mokelumne River, making this a welcoming home where salmon can survive and thrive,” said Jose Setka, EBMUD Manager of Fisheries and Wildlife. “The strategies at work are proving successful and are leading to a robust population of salmon in this river.”

Setka said the record salmon returns are a result of efforts that have focused on fine-tuning water operations, including managing cold water in Camanche and Pardee reservoirs to maintain good spawning conditions, releasing pulse flows of 1,500 cfs from Camanche Dam to attract fish, restoring gravel habitat and using tagging data to evaluate hatchery release strategies. Additional measures include transporting juvenile salmon by barge and feeding them a specialized diet to assist the fish in transferring from freshwater to seawater.

Another major factor he cited is the partnership they have developed with the federal agencies, including the Bureau of Reclamation and the U.S. Fish and Wildlife Service to close the Delta Cross Channel Gates to prevent Mokelumne fish from straying into other Central Valley rivers. “Last year the gates were closed in late September while this year they were closed in early November,” he noted.

Before 1998 when the Mokelumne River Setttlement Agreement went into effect, the average run was 4,000 fish. Since then, the run has averaged 9,541 fish per year.

As salmon returns on other Central Valley streams, including the American and upper section of the Sacramento, have declined in recent years, the Mokelumne’s contribution to the salmon industry has grown in significance. The Mokelumne River salmon population contributed approximately 20 percent of the commercial and 35 percent of the recreational catch off the coast of California in 2017, according to Tracy Morales of EBMUD.

“The partnership between the East Bay Municipal Utility District and the California Department of Fish and Wildlife is one characterized by innovation, high-quality science and operations, and mutual respect,” confirmed Kevin Shaffer, chief of CDFW’s Fisheries Branch. “We’re seeing the benefits now with a healthy river and good returns of Chinook salmon to the river and hatchery.”

“Fishermen are so grateful to the fish hatchery staff – there is so much innovation that leads to much higher salmon returns,” said John McManus, President of the Golden Gate Salmon Association (GGSA). “One of the keys is they get support from EBMUD, an organization that has an openness to trying new things. There is a recognition of hostile conditions downstream – and they have to get around the hazards to increase fish survival. They have a very good staff that produces supper babies – the fish are well taken care of and strong.”

Setka said the ability to implement management actions that lead to positive outcomes in the Mokelumne River is due to engagement from a diverse group of stakeholders. Less than a decade ago the Mokelumne experienced one of the worse salmon returns on record.

“The efforts of all stakeholders within the Mokelumne have resulted in a sustained recovery. In addition to Lower Mokelumne River Partnership member agencies CDFW, United States Fish and Wildlife Service, National Marine Fisheries Service and EBMUD, stakeholders responsible for the overall improvements in the river include California Sportfishing Protection Alliance, North San Joaquin Water Conservation District, Woodbridge Irrigation District and landowners along the river,” according to EBMUD.

Anglers are currently gearing up for the steelhead opener on the upper section of the Mokelumne below the hatchery. The season is from Jan. 1 through Mar. 31 and again from the Fourth Saturday in May through July 15. The limit is one hatchery trout or one hatchery steelhead.

Then from July 16 through October 15, the limit in this section of river is two Chinook salmon and one hatchery trout or hatchery steelhead.
For more information, call the Mokelumne River Hatchery, (209) 759-3383.

Mokelumne River Fishing Regulations

The Mokelumne River (San Joaquin Co if open from Camanche Dam to Highway 99 bridge is open from Jan. 1 through Mar. 31 with a limit of 1 hatchery trout or 1 hatchery steelhead.

It reopens from Fourth Saturday in May through July 15 with a limit of 1 hatchery trout or 1 hatchery steelhead.

Form July 16 through Oct. 15, the limit is 1 hatchery trout or hatchery steelhead and Chinook salmon.

From the Highway 99 bridge to the Woodbridge Irrigation District Dam including Lodi Lake, the season is from Jan. 1 through July 15 with a limit of 1 hatchery trout or 1 hatchery steelhead,

From July 16 through Dec. 31, the limit is 1 hatchery trout or hatchery steelhead and 2 Chinook salmon.

The section between the Woodbridge Irrigation District Dam and the Lower Sacramento Road bridge is closed to all fishing all year.

The Mokelumne River and its tributary sloughs downstream of the Lower Sacramento Road bridge and east of Highway 160 and north of Highway 12 from Jan. 1 through July 15 has a limit of1 hatchery trout or 1 hatchery steelhead.

From July 16 through Dec. 16, the limit is 1 hatchery trout or hatchery steelhead and 2 Chinook salmon.

From Dec. 17 through Dec. 31. The limit is 1 hatchery trout or 1 hatchery steelhead

Improved Mokelumne Salmon & Steelhead Return Strategies

Stronger Pulses – Pulse flows reached higher magnitudes compared to recent years thanks to flood control waters released from Camanche Reservoir. These pulses provide cues for salmon to move up into the river. Additional pulses provided by reoperating Woodbridge Irrigation District Dam extended the period of pulses into November.

Gate Closures – To prevent straying of Sacramento and Mokelumne River salmon, CDFW coordinated closures of the Delta Cross Channel Gates on weekdays and reopened for weekend recreation beginning in September. 

Tagging Data – Using Coded Wire Tag data from returning fish, the agencies measured the effectiveness of releasing fish on outgoing tides and limiting releases to no more than two consecutive days from the same location to increase juvenile salmon survival.

Barging – The agencies have transported juvenile salmon from the Mokelumne River by barge and released them in the San Francisco Bay. Barging improves fish survival through the Delta and may also help with imprinting for juvenile salmon to re-trace their way to natal waters.

Transfer Diet – Juvenile salmon undergo an incredible physiological change when moving from freshwater to saltwater. To ease the initial stress, a specialized feed containing higher salt levels is fed to the juveniles in the weeks before the release.

Habitat Improvement – EBMUD and DFW have spent nearly two decades developing and implementing a plan to improve spawning and rearing habitat in the river below Camanche Dam.