Trout Kill Blamed On Dam Testing

Pictured are seven of the 11 trout killed below Matilija Dam during a seismic test of the dam that dried up a pool in the Ventura River.

By Daryl Kelley
Eleven endangered Southern steelhead trout, or their more common rainbow trout relatives, were killed in the Ventura River last month, when an earthquake safety test of Matilija Dam and dry weather conditions stranded the fish without water in the upper Ventura River, officials said this week.
“It was a combination of those factors,” said Steve Wickstrum, general manager of the Casitas Municipal Water District, which shut off the flow of water from the dam’s reservoir for a few hours on June 14, so a county agency could test it for structural safety.
It was the largest of kill of steelhead or rainbow trout in recent memory, Wickstrum said.
Seven dead fish were found the day after the dam water was shut off, and four more died after they were relocated to river pools.
Casitas has asked federal and state agencies to investigate the incident, and to determine whether the dead fish are actually the ocean-to-river southern steelhead, a unique form of rainbow trout, or the freshwater rainbow.
The fish look the same when the steelhead are young. And none of the dead fish — between 5 and 10 inches long — was large enough to be immediately identified as the larger steelhead. Lab tests of the dead fish’s earbones will show their type.
“They were just too stressed out to survive,” said Scott Lewis, fisheries program manager for Casitas, of the four fish workers had tried to save. Two did survive.
Lewis reported the deaths this week in a report to the Casitas board of directors, some of whom were concerned that they were not told of the incident before.
“This is significant,” said Director Richard Handley in an interview. “Here we are spending $9 million on a fish ladder and this happens. We need to be more vigilant about what we do in the river. These fish should have been trapped and moved ahead of time.”
In his report to the board, Lewis said: “The cause of the mortalities was most likely due to the lack of water as a result of the water flowing through Matilija Dam being shut off on June 14.”
The water was shut off at the direction of the county Watershed Protection District, Lewis wrote, so the agency could test the dam’s safety. Vibrations from flowing water near test points would have disrupted the procedure, he said.
Since the fish deaths, Casitas has asked county officials if they could move the test points away from the dam’s release pipe, so the water flow would be maintained at all times, Wickstrum said.
The water agency has also asked federal officials who oversee the southern steelhead recovery program for guidelines on whether to save stranded fish and how to handle the recovery, he said.
“We’ve asked for direction, but there has been no protocol to date for rescuing the fish when the river runs dry, or where to rescue them to,” he said.
The U.S. National Marine Fisheries Service oversees the steelhead program. And Casitas biologist Lewis said the federal agency is apparently attempting to address the rescue question on a regional basis.
“There’s a question of whether we can rescue (them),” Lewis said. Because of record dry conditions on the river, “we asked many weeks before this incident if we could do that, and they didn’t have a plan. It sounded like they wanted to work on a more regional approach.”
The southern steelhead was declared an endangered species in 1997, after its numbers dwindled from thousands to a few hundred from Santa Barbara south. Only about 100 adult steelhead remain in the Ventura River watershed, federal officials estimate.
A key question is whether the dead fish were, in fact, steelhead, officials said.
That is important, partly because the federal government has required Oak View-based Casitas to spend $9 million to build a fish ladder so the steelhead can migrate up the Ventura River and then return to the ocean. Casitas must also provide between $1 million and $2 million worth of water a year so the fish can migrate. A costly federal lawsuit to reimburse the water agency for the expenditures is before a federal court.
Considering efforts and money to save the steelhead, Wickstrum said federal government’s lack of a plan to rescue the fish when stranded “is ironic.”
As for county dam testing procedures, watershed protection director Jeff Pratt said he’d heard nothing about the fish kill, but would look into whether his staff can change procedures so water is not shut off during twice-a-year seismic testing.
“We’d do anything we can not to kill the fish,” he said. “We’re going to do anything in our power not to kill the fish.”