River Health Update: Biologists and volunteers return to work on the upper river fish study

dozer

STAYING FOCUSED on the fish study at hand, volunteers get some company in the background. (Credit RCDSMM Stream Team)

By Rosi Dagit
Guest Contributor

On our return to Sepulveda Basin, to continue the upper river fish survey, we captured 203 fish, a far cry from the more than 3,600 tilapia fry caught this time last year.

There had been the first major rain of the season the day before, on Monday, Nov. 21, with between 0.75-1.25 inches over the LA River basin. Sediment and the remains of several homeless encampments were in our car park site. Muck was unconsolidated and varied from 1-6 inches deep. We couldn’t walk far upstream, starting 30 yards to the underpass at Burbank Blvd. because the water was too deep but flow in the main stem concrete area where the sample sites are located was shallow. Most of the vegetation along the banks was gone with just a few patches of water primrose (Ludwigia hexapetala), a few cattails and some willows closer to the bridge were all that remained.

The majority of fish were non-native juvenile Tilapia sp. and Gambusia affinis. Both of these species are common and abundant throughout the LA River, where they were initially released to control mosquito larvae. Samples of both species, as well as fathead minnow, juvenile red swamp crayfish and Asiatic clams were also collected and frozen for toxicology testing.

A single adult Plecostomus (Hypostomus plecostomus), which is a common aquarium fish, was also found washed up on the concrete bank at site 2. It recovered when placed into cool water, but was collected for toxicology testing.

An Army Corps ‘dozer and dump truck moved sediment and debris out of the concrete channel, according to their management permit. The site supervisor kindly allowed us to complete our site 1 and 2 sampling before they moved heavy equipment into that area. The rest of our six sites were upstream of their work area.

plecostomus

YOU NEVER KNOW when an aquarium dweller will show up in the LA River, in this case the gnarly Plecostomus. (Credit RCDSMM Stream Team)

Following collection of what looked like an arroyo chub (but was later confirmed to be a fathead minnow) at site 1, just downstream of the disturbance in the channel, we contacted the California Department of Fish and Game about this potential threat to any other arroyo chub that might have washed down.

Dagit is the Senior Conservation Biologist, Resource Conservation District of the Santa Monica Mountains.

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More than 3,600 tilapia fry netted in upper river fish survey

BIOLOGISTS Sabrina Drill (left) and Rosi Dagit inspect part of the tilapia haul. (William Preston Bowling)

BIOLOGISTS Sabrina Drill (left) and Rosi Dagit inspect part of the tilapia haul. (William Preston Bowling)

By Rosi Dagit

Guest contributor
Looks like we captured 3,699 fish, the majority of which were juvenile tilapia under 1 inch. Based on the few larger (up to 3 inches) fish, most appeared to be redbreasted tilapia (Tilapia rendalli), but that is not yet verified with the voucher specimens.  These fish can breed year around in warm waters, and it was quite interesting to find such young fish at this time of year, but water temperatures were 24-27 degree C. (75-81 degrees F.), which is pretty warm. They can reach up to 18 inches and live for up to seven years.
They are native to Africa, and are primarily herbivores that spawn in the substrate and guard their nests.  They are considered to be competitors with native fish for food and spawning areas, and high densities of fish can negatively impact native aquatic vegetation.
In other areas, they have not survived strong flows or colder temperatures, so it will be really interesting to see if they make it through the winter El Nino.
SEINE NETS yield 3,000 tilapia fry in Haskell Creek above Sepulveda Dam on Friday. (William Preston Bowling)

SEINE NETS yield more than 3,600 tilapia fry in Haskell Creek above Sepulveda Dam on Friday. (William Preston Bowling)

No steelhead in L.A. River’s mouth not the whole story

Twenty-five-inch steelhead trout caught in the Los Angeles River near Glendale, in January, 1940. (Courtesy family of Dr. Charles L. Hogue)

Twenty-five-inch steelhead trout caught in the Los Angeles River near Glendale, in January, 1940. (Courtesy family of Dr. Charles L. Hogue)

Every so often, news stories come along that seem to tell the story, but, when enveloped in a larger context, turn out to be a shadow of the actual truth. Reading yesterday’s Los Angeles Times, old school (in paper!), I found environmental writer Louis Sahagun’s “Searching for the elusive steelhead trout,” to be in need of context and rebuttal.

Those newshounds among you know that Vox, formed by some former Washington Post staffers, thrives on its policy of “understanding the news.” Context in this digital age is king.

If I’d never fly-fished or reported on the L.A. River, I would have read Sahagun’s piece and asked “Why would anyone attempt a fish study in this toxic waste water?” and probably had a very good laugh at the photograph of the fool from Trout Unlimited with a sock attached to his line, and snickered at the abandoned shopping cart shot.

But, as it stands, I have a platform to cry foul on this piece. I started lariverflyfishing some four years ago with the tagline “fishing for carp, waiting for steelhead,” and have amassed over 1,000 followers and 46,000-plus hits as of this writing.

For those of you who actually do enjoy recreational fishing in Glendale Narrows, you know this story doesn’t begin to tell the broader context of our river.

And for those of you who participated in the latest clean-up efforts, you know that if Friends of the Los Angeles River, the organization that has organized clean-ups for the past 25 years, had gotten a piece of this area, the junk would have been removed.

FOLAR released “State of the River: The Fish Study” six years ago. This singular Los Angeles River study combed four areas for fish, a Glendale site, Newell site, Figueroa site and a Riverside site. The seine nets captured carp, tilapia and sunfish in significant numbers. Because of this study I realized an LARFF contributor had really caught a legend when he recently captured a largemouth bass, because only one appeared in the study, as compared to nearly 250 tilapia.

The most telling lack of context in the Times piece is not mentioning that this study was funded to complete the work begun in 2008. As the study says:

“These coastal and estuarine species will not be

A steelhead rendered on the Guardians of the River gate. Once these oceangoing trout ran up the river. Time for them to return.

A steelhead rendered on the Guardians of the River gate. Once these oceangoing trout ran up the river. Time for them to return.


discussed further here, but will be present and of
concern when work extends to the lower Los Angeles
River. It is becoming increasingly apparent also that
coastal lagoons in and near the mouths of central
and Southern California rivers are very important to
at least one of the two anadramous species known
to have occurred in the Los Angeles River system,
steelhead trout. Thus, they are also important to their
ability to return, spawn, and establish a population.”

A piece that continues to get hits on LARFF is one I originally wrote for California Fly Fisherman magazine. Although events have moved forward significantly since I penned “Will steelhead ever return to the L.A. River” in 2012, most of it remains sound, including this quote from the river’s noted poet:

“Maybe next time they rechannelize it, they do it to the specifications of the steelhead,” mused Lewis MacAdams. “Have a panel of steelhead, fins up, fins down. Let the steelhead decide the shape of the channel. I’ve always felt that what we were doing was calling things home. You know, ‘it’s OK to come back’. There is something to that.”

See you on the river, Jim Burns