Update: Lake San Antonio closed due to large-scale fish die-off
Update posted July 10:
Number of fish impacted is increasing, reason for die-off remains unknown.
– Out of abundance of caution for public health, the County of Monterey Parks Department is closing the Lake San Antonio facility due to a large-scale fish die-off from an unknown cause.
On July 5, staff reportedly noticed that dead baitfish, mostly shad, began washing up on the shore around Lake San Antonio and immediately contacted California Department of Fish and Wildlife (CDFW) to report the situation. At that time, the CDFW fisheries biologist stated the fish die-off was most likely due to the high temperatures and low dissolved oxygen level in the water and that the situation most likely did not present a risk to the public. Parks staff also contacted the Water Resources Agency (WRA), State Water Resources Control Board, and Environmental Health Bureau.
The fish die-off has continued with larger species such as bass, catfish, crappie, carp, and trout being impacted. The above photos include a 3–4-pound bass.
CDFW, WRA, and EHB are working together to try to determine a cause of the die-off. CDFW has tested the dissolved oxygen in the water which came back in the normal range and is also collected fish samples for testing. With the continued die-off, especially of larger species that should not be impacted under the current environmental conditions, EHB has issued a “precautionary measure directive” to Parks to keep the public from boating, fishing, and swimming in the lake.
With that directive and due to the lake’s South Shore water system being surface drawn, county parks staff has made the difficult decision to close the entire Lake San Antonio facility until this situation has been resolved.
“While this may be a natural occurrence, until it is known that this is not being caused from a biological vector or pollutant that could cause harm to the public, we must keep the public safe by closing the park,” said County of Monterey Chief of Parks Bryan Flores.
Parks staff and Rangers are contacting the small number of campers and boaters currently at the lake to inform them that they will need to vacate the facility by Noon on Wednesday, July 10, 2024.
Effective immediately, no new guests or lake users are being admitted. Once a cause is determined, we will share that information with the public and when the lake can be reopened. The next task is to clean up and dispose of the dead fish. There is no estimate at this point on when clean-up could be complete or reopening could occur.
Original story posted July 9:
Lake San Antonio reports large fish die-off event
– The California Department of Fish and Wildlife has been advised of a large fish death event occurring at Lake San Antonio. Officials believe the die-off is due to extreme temperature changes causing oxygen depletion in the water.
There is no believed risk to humans or pets, according to Maia Carroll, Public Information Officer for the County of Monterey. Lake visitors can still fish but are advised to leave the dead fish alone.
