What is Tidepooling

Crab tucked into rock crevice

What is tidepooling? Simply, when the ocean tide goes out and exposes a rocky shoreline, pools of water remain, containing little critters of sea life to inspect.

I am not sure what prompted me to look at the tide charts on Wednesday night. But I am glad I did. The prediction for Thursday, July 4th was a -1.55 feet tide elevation at 7:04 a.m.

What is a negative tide? It turns out that the low tide is set at an elevation of zero and is calculated as the average of the lower low water heights of each tidal day, observed between 1983 through 2001. Therefore, a negative tide of -1.55 means that the low tide is considerably lower than the low of the lows. I was told by one beach-goer that this low of a tide only happens 6 times a year.

In simple terms, this means that areas that are typically covered by water, even during low tide, are exposed for a short interval. This provides a great chance to see even more sea critters than normal.

A co-worker told me Sculptured Beach was a must-see place. But, it can only be accessed during low tide. And, via a Google search, I found out it is also good for tidepooling.

I estimated it would take about an hour to drive, and 3/4 hour to hike. I wanted to be there by 6:15 a.m. So, I got up at 4 a.m., ate breakfast, packed a lunch, and made the journey.

Sculptured Beach Point Reyes National Seashore
Sculptured Beach is a rocky coastline within Point Reyes National Seashore. These areas are extremely dangerous during a high tide since the water is literally lapping at the edge of the cliff. The only exit is down the beach, before the tide rolls in. Sony a7R III + 24-105mm lens @24 mm, ISO 400, f/22, 1/8s. ©Stanley Buman. All Rights Reserved.

A lot of sea life can be found in the pools of trapped water. But, I prefer to search the exposed rocks for sea life. Sea stars have always caught my attention. Disappointingly, I only saw three of them. I met a woman at Sculptured Beach who had written a paper on the loss of sea stars. It turns out the loss is linked to climate change. Just a 4 degree rise in water temperature occurred, allowing a disease to flourish and kill high numbers of the sea stars. Other types of sea life were also directly impacted by the disease.

Additionally, there were indirect effects. Sea stars are high up in the food-chain. They eat urchins. Left unchecked, the urchin population exploded. Urchins mowed down the underwater kelp forests which supported a variety of fish, crabs, and other creatures.

Pink Orange Starfish - Point Reyes National Seashore
Sea stars are high up in the food-chain. A rise in water temperature allowed a disease to spread, killing off high numbers of them. Sony a7R III + 24-105mm lens @96 mm, ISO 400, f/22, 1/8s. ©Stanley Buman. All Rights Reserved.

Two days later, I checked out Duxbury Reef at low tide; another great tidepooling area just south of Point Reyes National Seashore. While walking on the beach, I noticed little critters crawling in rock crevices as I approached. I found numerous types of crabs that saw me as a threat and sought shelter.

Crab tucked into rock crevice
This little crab hid in a rock crevice as I approached. Sony a9 + 100-400mm lens @386 mm, ISO 400, f/8, 1/30s. ©Stanley Buman. All Rights Reserved.

I can get excited about spending time on rocky beaches. There is so much sea life to investigate. I find sandy beaches boring. There is very little to do but sit; well, unless there is bird activity.