Ecological Musings: Pillar Point, Half Moon Bay, CA -- May 2nd, 2025

Background:

I’m currently taking a California Ecology class. One of the class assignments is to keep a field journal of each of our weekly trips. Today’s journal is about one of my favorite locations of all time: the tide pools at Pillar Point in Half Moon Bay, CA.

Baseline Data

Name: Pillar Point

Address: V300 W Point Ave, Half Moon Bay, CA 94019

Coordinates: 37.5022° N, 122.4808° W

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Date: Friday, May 2, 2025
Time: 9:00 AM – 1:30 PM

🌤️ Weather Overview

  • Temperature:

    • Morning (9:00 AM): Approximately 56°F (13°C)

    • Late Morning (12:00 PM): Approximately 59°F (15°C)

  • Cloud Cover: Mostly cloudy with occasional sun breaks

  • Wind:

    • Direction: Southwest to West

    • Speed: 10–12 mph

  • Humidity: High, around 85–90%

  • Precipitation: No precipitation reported

I first went to Pillar Point in November of 2024 with my best friends Anne and Kristina and Anne’s boyfriend Daniel. Initially, we went to fish for sea urchins and mussels. I’d gone fishing once as a small child, but never had never gone harvesting before. It was something I kept seeing on really cool videos like this one, but I was always too hesitant to try it myself. It’s funny now, looking back, because I remember a time when I was like “yeah! one day I’m going to experience that!”. But deep down inside, I could never quite envision when or how that would happen. Now, today, I feel almost seasoned at doing this. It’s my 3rd time harvesting sea urchins and mussels from Pillar Point and, each time, I think I get a little better at it. I can comfortably harvest the urchins without breaking their shells or disrupting the local rock bed. I can also more comfortably identify the right mussels to pick and pick them out without disturbing the other mussels around them.

But today’s field trip in and of itself wasn’t about fishing or harvesting (though I did that too). Every Pillar Point field trip from Bio 1C to Bio 15 has been about developing a better understanding of the region’s local ecology. For example, I had always described the sea urchins at Pillar Point as being an invasive species because news media kept describing it as an “invasive species that is decimating our local kelp forests”. Turns out, however, that these sea urchins are actually a local population and not invasive. The problem is, climate change induced issues from the past few years led to a lack of predation for sea urchins along the California coastline. The natural predators for sea urchins include sea otters and sunflower sea stars. The sea otter population suffered a decline due to a combination of ecological changes, historical exploitation, and modern human-related threats. Meanwhile, sunflower sea stars were devastated, from 2013-2015, by sea star wasting disease. Furthermore, the 2014-2016 marine heatwave resulted in warm, nutrient-poor water along the coast. Kelp growth slowed down because of this. At the same time, sea urchin populations (which are resilient in their ability to survive starvation) began reproducing rapidly and consuming the remaining kelp. The combination of all of this led to the modern problem that we have today: too many sea urchins and too little kelp. Kelp is a source of food for a lot of different marine organisms and the overpopulation of sea urchins makes it so that other organisms are unable have access to enough kelp. Long story short: sea urchins are not invasive, but climate change has led to a situation where they have been able to over-proliferate and, as a result, are over-consuming resources.

Now, I just happen to love uni. It also happens to be incredibly expensive at most restaurants. Uni is best eaten fresh, and the best uni has honestly come from the sea urchins I have directly harvested at Pillar Point. All of this coupled with the fact that the overpopulation of sea urchins in the area has led to a bit of an ecological crisis makes it so that harvesting uni is both enjoyable and environmentally friendly!

The octopus Abdullah came across.

Ironically, however, I’m apparently not the only person who feels this way. So many people realized this that they began harvesting sea urchins too. So, at this point, I don’t even think they’re nearly as overpopulated as they once were.

We saw a lot of different cool things at Pillar Point including what appeared to be a scorpion fish, lots of mussels, tiny fish and eels, hermit crabs, and more.

The scorpion fish we came across.

My favorite story about the trip, by far, is as follows. My little brother, who takes the class with me, showed up super late, hung around by the tide pools for a bit, called it quits within under an hour, and went back to the beach shortly after. Meanwhile, the rest of us are running around the tide pools looking for what our professor, Gillian, describes as “the coolest possible thing to see in the tidepools”: an octopus. As we’re looking, suddenly one of our classmates comes over and says, “Hey, Huda! Your brother saw the octopus” I looked back and her and was like “ain’t no way. AIN’T NO WAY”. This kid, on his way back to the beach, lo and behold came across an octopus. Lucky for us, he took a video of it. We tried to find it amongst the tide pools afterwards, but it had long since scuttled away.

After we left the tide pools, we enjoyed some fresh food at the iconic Barbara’s Fish Trap in Half Moon Bay. I always get their fish and chips and it never misses. Their clam chowder slaps too.

We drove to Johnson pier, inhaled our food in our cars, and then walked over to some of the docks. The class took the opportunity to look for sea sponges and sea stars under the dock wood, but I’d already done that the quarter before in Bio 1C, so I took the opportunity to draw a sea star with my oil pastels.

A little harbor seal stuck its head out of the water to greet us while we sat on the docks. It was very cute!

Afterwards, a couple friends and I stopped for ciders at a nearby spot that overlooked the water.

Overall, it was an absolutely wonderful day.

But this tends to be the case whenever I visit Pillar Point! It’s such a special place!

A 7-minute oil pastel drawing I did, on the docks, of one of the sea stars I saw in the tide pools.

Drawing on the docks has to be one of my favorite places to draw. It was so peaceful and we kept seeing this adorable harbor seal pop its head out to playfully engage with us. 🦭

huda .