Devastation of Kelp Forests at Shaw's Cove

[HBVetera n2312]

Was wondering if anyone had a clue as to why the kelp at Shaw's Cove is gone? I took the first pic on June 23rd, second pic yesterday September 1st. Taken at the same spot. I dive here quite a bit and was surprised to see how quickly the kelp disappeared.

Thanks in advance!

 

[MaxBottomtime]

The water has been in the 70s. That will do it.

 

[Sam Miller III]

@HBVetera n2312

Kelp health is dependent on many factors - water temperature sub striate -ever changing topography - pollution etc

Currently the water is unseasonably warm.

Many years ago the late Dr. Richard Terry, of Anaheim, did his USC doctorate on Kelp along the California coast
He reviewed maps and charts (Maps are for land Charts are for water) dating back to the 16th century. He discovered that kelp was very erratic in growth patterns and transitional in locations.

As a relative new diver you might want to google Dr. Terry -- He is the only American to have a Sea Mont named in his honor in the Challenger deep of the Marianas trench-- and from Anaheim California !

SDM

 

[drbill]

Temperatures above about 68° F for a period of about two weeks will cause giant kelp (Macrocystis) to be unable to metabolize properly and die off. Certainly other factors like rocky substrate being covered by sand or nutrient depletion also play a role. I did my Ph.D. research on shifting patterns of giant kelp around Catalina Island back in the 90s and there are other factors as well. See http://www.starthrower.org/research/kelpgis/ijmargeo.htm

We are seeing die-offs here on the island but mostly in the upper water column where temps have been in the low- to mid-70s for some time. Below the thermocline where temps are in the upper 50s to lower 60s, kelp is doing better.

 

[HBVetera n2312]

Makes sense. My computer showed 65 degrees in June and 59 degrees on September 1. Nothing to say what the temps where in between my measurements, which were taken at approximately 40 fsw during the morning hours. I was just shocked at the amount of loss.

Great information, thanks again for the replies.