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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California Killifish surprise catch for fish study

I don’t know how biologist Rosi Dagit does it but every time she calls a meeting of the fishing-for-science clan, the mercury breaks another record. Today was no exception, as around 25 sweating volunteers traveled to Willow Street in Long Beach for the last effort to see what could be caught in this important area where the Los Angeles River runs into the ocean.

We saw a dozen or so mullet, as they danced around our side of the lagoon, bobbing and weaving to invisible underwater music. Four of us tried everything in the flybox, from San Juan worm, to topside stimulator. What goes into the record book is but a shadow of what’s really in the water.

The kayak crew, pulling a net, came up empty, a disappointment.

John Tegmeyer fashioned his own boilies — like the Brits do, but with a dose of Tapatio Sauce thrown in for color — and came very close to landing a large carp.

Meanwhile, Zino Nakasuji fooled a 7-pound common carp with a pale egg pattern.

But Dabin Lee of Los Angeles handscooped the most important catch of the day — a tiny California Killifish, which is a native and lives in brackish water.

“I do it all the time,” Lee said, referring to her habit of catching small fish in her hands. It made for a remarkable end to four attempts over the last year and a half to document exactly what lives in this part of the river.

The great hope is to spot a steelhead.

“I just recently  got a picture of one from Cabrillo Pier,” Dagit said.

And, of course, that is the lofty dream of so many of us, that the Southern California Steelhead, currently an endangered species, will make its comeback in tandem with the river renewal. With the anticipated El Niño this winter, we may yet get that opportunity, when fish return from the ocean, hoping to ride high water in to their inland spawning grounds.

And if you missed this part of the survey, you’ll have another opportunity. Next year, Dagit is targeting the Sepuveda Dam area in the San Fernando Valley.

Meanwhile, I hope you enjoy this silly video from the day.

 

See you on the river, Jim Burns

 

 

 

 

 

Biologists tentatively ID mystery L.A. River bass

Our mystery bass. (Roland Trevino)

Our mystery bass. (Roland Trevino)

Another view of the mystery bass. (Roland Trevino)

Another view of the mystery bass. (Roland Trevino)

One of the best parts of fishing our river is you never know what you’re going to pull out of it. In the old days, this comment would elicit some snark about a “really brown trout,” haha. But today, we discuss what in the heck are these crazy bass that Roland Trevino pulled from one section?

Take a look at his pics and see how white the sides are.

Rosi Dagit, Senior Conservation Biologist and Certified Arborist for the Resource Conservation District of the Santa Monica Mountains, agreed that they were “strange-looking bass” because “the white-side blotches are quite noticeable” in the pics we showed her.

She enlisted the help of Camm Swift, emeritus PhD from the Natural History Museum of Los Angeles.

“These appear to be very faded out largemouth bass, but it would be good to see both dorsal fins elevated. Maybe they came from fairly turbid water,or were held in a white bucket for a time and lost lots of color?” he wrote in an email to Dagit.  “There is a slight possibility they are white bass or white perch, Morone chrysops or M. americanus, but they have much larger anal fin spines than largemouth bass and do not appear to be present in these fish.

“Both of these species are from the eastern United States (as are largemouth bass for that matter!) and the white bass is known from a few places in central California but unlikely in L. A.   Thus, without some other convincing evidence I would call them largemouth bass.”

Swift also offered some advice on how to help the experts positively ID a mystery fish.
“If it’s hard to keep the fish, a good photograph from the side with the fins spread is useful to get close, anyhow.  Putting them in a water-filled Ziploc or one of those small plexiglass boxes like fish photographers use can suffice.  Usually the fish will expand its fins when swimming or resting in  one of those.”
For my part, I’m still not so sure. If anyone catches another white mystery bass, let’s get a better shot and see what the biologists say.
See you on the river, Jim Burns