Dive_Blog_2024_08_06_PL4

Purpose: Watching El Nino Underwater, Swapping of TLCs

August 6 2024

By: William Hagey

Point Loma – PL4

Vessels: The (Mighty) Kelpfish

Divers: William Hagey, Ronan Gray, and Jim Melrod

Topside Support: Glenn Hefner

Surface conditions: Short period 1 to 2 foot mixed swell. Foggy becoming sunny.

Visibility: 35 ft

Water Temperature: 51° F

Current: Very little

Dive: Time in: 08:10AM, Dive length 25

Depth Max: 74 ft

Purpose: Swap out TLCs, 50 Meter transect. (No transect done, short on time equipment issues, my mask, and dive transmitter/computer.)

Summary: Two TLCs and Mini DOT were recovered and one of each was left. Video was taken by W Hagey with new GoPro 12. Ronan took with his wide angle action cam. Jim Melrod took stills and video later.

Here’s a video of our dive that Ronan Gray made:

August 6, 2024 WENU Project Dive 1 (youtube.com)

Here’s the video made from the time-lapse camera from the past two months:

2024 06 4 Thru 2024 08 06 USA CA PtLoma PL4 PMRG1

Equipment Notes: We recovered two TLCs that were doing a side by side test of the anti-fouling options. Both TLCs took full deployments of images. The slave light and UVC lights were still working with plenty of extra battery life. TLC PMRG1 was the main TLC with MiniDot SN697549, slave light – with a half second delay and the wiper set for 30 seconds every 12 hours. NOAA 15 was the extra TLC with the UVC light. Zincs were added to the battery housing on both ends – they worked well. A zinc was also added to the UV-C light bracket. It was completely used. I didn’t expect this since the bracket was 300 series stainless steel; the zinc was small and easily replaced. .

The slave and UV light pack had 5 AH at 14.8V (two battery packs diode ORed together. This was plenty of power. 

The replacement TLC had UVC light set for 30 seconds every 6 hours – twice as often as last time. The slave light has a half second delay.. We are still dialing in the timing for this. Zincs were added to the battery housing on both ends.

Habitat characteristics and surveys: Hardscape with pits and a gentle slope. There is upper and lower story macroalgae that is evidently young. This location is well known since it has been a release site. Again, this was pretty much the same as two months ago.

Methods: We dropped anchor next at PL40A coordinates and the lead line was right there. Ronan started his dive a head of Jim and me. But, I had equipment troubles. Jim was generous enough to let me go on the dive without him. By the time I got to the TLCs, Ronan only had time to take up one of the TLCs. I quickly swapped the TLCs and followed him back up to the surface. 

A 50 meter transect was not run because we were low in time due to my equipment issues. Ronan and I both did collect video of the area which is at least some information. 

Abalone: We were so focused on our task, with the very low light and strong current so we didn’t look around for abalone.

Dive comments: Salps! ! ! It was like diving in an artist’s rendition of a 200 million old sea. The salps were everywhere and the water was blue clear like mid ocean water!

This is the oxygen and temperature profile from this deployment

See photos below:

To test anti fouling we deployed two TLCs. One with a wiper set for every 12 hours and the other with a UV light set for 30 seconds every 12 hours. 

The upper image is from the newly recovered TLC and the image below is from the TLC that was just recovered in April. Note, good and similar alignment.

This image is from two deployments ago.

This shows the TLCs as we left them two months ago.