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Major fish die off at Laguna Niguel Lake sparks outrage throughout angling community, local, residents
BY MIKE STEVENS
WON Staff Writer
LAGUNA NIGUEL— After receiving a message from a concerned angler about a situation at Laguna Niguel Lake (LNL), WON Tournament Director Billy Egan headed over to check it out. What he saw was an alarming scene centered around a massive fish kill and algae-choked water. Egan proceeded to make an on-the-spot video that was posted to Western Outdoor News’ social media channels, and it has since been picked up and circulated throughout the community.
“I live in Orange County, I grew up here in Laguna Niguel, and I started my whole fishing experience at (Laguna) Niguel Regional Park,” said Egan. “There has been a lot of changes at this lake that are really affecting our youth, their ability to get outdoors and to really get engaged with fishing. This is what’s currently going on here at Laguna Niguel Lake, the regional park run by OC Parks. A park that was donated to them years ago. This was farmland.”
The video then cuts to hundreds of dead, floating fish in just a small portion of the lake. According to Egan, there were “thousands” of them found throughout the lake, and it included a lot of trophy bass exceeding 10 pounds as well as panfish and other species.
“This is from mismanagement of water,” Egan continued. “I’m going to get to the bottom of this, but you as a citizen of south Orange County, and as an outdoorsman, fisherman, an enthusiast of the outdoors, should call your representatives and put people who are in charge on call and on notice that this is unacceptable.”
Egan did talk to someone who was part of LNL’s management years ago who wished to remain anonymous.
“Low dissolved oxygen,” he said. “It’s a shallow lake with lots of phosphorus from all the ducks and geese and maybe fertilizers from the grass, and an insufficient aeration system that cannot break down bottom muck resulting in poor water quality. Bad management.”
He went on to say LNL is a city lake, “and no city manages their ponds correctly” with a biologist to monitor the habitat due to the added cost involved. After WON posted the video, members of the angling community said they noticed the aerators at LNL were off for weeks, but OC Parks has yet to comment on that matter.
“If the water is more than 85 degrees their air system should only be on from 9 p.m. to 10 a.m.” he said. “What aeration does is mix the water to prevent a thermocline from forming. Hot water on top and colder lower oxygen water and depth is what a thermocline does. You don’t want to mix high-heat water deep as the fish have no temperature refuge. What they should have is surface agitators (fountains) to break water tension and get oxygen in the surface layers during the day. In low D.O. (dissolved oxygen) events, it is the largest fish that die first as they have a higher oxygen demand. D.O. level for bass and bluegill to feed and grow is 5 to 8 ppm. Bass stress at 3 ppm and bigger fish start dying after a few days of 1 to 2 ppm. The reason why trout don’t live in shallow ponds or lakes even is not water temp, it is D.O. Trout require 8 ppm minimum.”
Egan is nowhere close to standing as the only member of the Southern California sportfishing industry with roots in fishing LNL.
“I fished that lake religiously since I was a little kid,” said Captain Max Neue of the Pacific Voyager out of Seaforth Sportfishing. “Even with the fishing pressure, it was a great fishery.”
After cleaning the mess, OC Parks released the following statement:
OC Parks is saddened by the recent fish die off that occurred at Laguna Niguel Lake within Laguna Niguel Regional Park and have been working around the clock to address the situation. We understand the importance these lakes have for the community and want to stress that we are taking this very seriously.
While we cannot definitively say exactly what caused this to happen, as fish die offs can occur naturally from time to time, a combination of factors could have contributed to the situation such as changing weather, increase in water temperature, a lower-than-average rainfall year, the presence of algae and potential equipment malfunction.
As of now, it appears the fish die off was due to a change in weather causing the water temperature to increase, particularly in the shallow waters at the south end of the lake where most of the fish were seen on the surface. When this happens, there is less oxygen in the water, which is critical to fish survival. Catfish can tolerate the warmer, desert-like conditions present in Laguna Niguel Lake this time of year, but other fish are more affected, seemingly leading to this fish die-off. While there is no way to control the water temperature of the lake, further steps are being taken that could possibly help mitigate this from occurring in the future.
OC Parks cares deeply about providing the necessary conditions for fish to survive and thrive in the lakes under our management. All equipment has been thoroughly checked to certify everything is functioning properly. Additionally, we are continuing to monitor water temperature and oxygen levels within the lake to ensure conditions remain stable.
According to weather data, the high in Laguna Niguel reached 81 degrees on July 10, and in the two weeks that followed, it fluctuated between 73 and 75 degrees. The high only exceeded that range when it reached 77 degrees on July 17.
WON has been contacted by the mayor of Laguna Niguel and was invited to attend an upcoming city council meeting.
