Lake San Antonio Closed Due to Large Scale Fish Die Off; Number of Fish Impacted is Increasing and Reason for Die Off Remains Unknown

July 9, 2024-Out of abundance of caution for public health, County of Monterey Parks is closing the Lake San Antonio facility due to a large-scale fish die off from an unknown cause.

On July 5, 2024, Parks staff 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.

 

Unfortunately, the fish die off has continued with larger species such as bass, catfish, crappie, carp, and trout being impacted. Attached 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,” explains 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 12 pm on Wednesday, July 10, 2024.

 

Effective immediately, no new guests or lake users are being admitted. Once a cause is determined information will be shared 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.