A tale of sand, a shell, and a seal

The new moon is tonight, which of course means that we are in spring tides. Yesterday afternoon my friend and colleague Scott joined me for my first visit to the intertidal in 2016. And where to go for this inaugural field excursion of the new year, but to Franklin Point? Low tide was at 15:53 yesterday, so we met up at 14:00, stopped to fill up the gas tank, and headed up the coast. Expecting it to be crazy windy as afternoons tend to be on the coast, I had dressed in extra layers. Scott and I were surprised to emerge from the car and find it wasn’t windy at all, so even though the air temperature was cool at least we didn’t have to deal with any significant amount of windchill factor.

Hiking over the dunes we saw Unusual Thing #1–a bridal photo shoot. A couple of stretches of the trail are covered by a boardwalk, and on the first of these we encountered a bride decked out in full regalia–wedding dress, flowers, hair, make-up–and two photographers. They were very nice and let us pass through in our decidedly inelegant boots and field gear. I didn’t think it would be very nice to take their picture. However, I did think that they’d lucked out and gotten a great day for photography: the aforementioned lack of wind meant that the bride wasn’t freezing in her slip of a wedding dress, and the afternoon light was flat so there were no shadows or harsh glare.

Descending onto the beach we came across Unusual Thing #2–an elephant seal.

It is e-seal haul-out time at Año Nuevo State Park a few miles down the road from Franklin Point, and I’ve seen them on the beach a few times before. This was the first time I’d seen an adult male, though, and he was HUGE! Without being stupid and going over to stand next to this animal it’s hard to depict how large he is, and unfortunately there wasn’t anything in the vicinity to give a sense of scale. So trust me, or look it up for yourself, male elephant seals are ginormous. This big guy was taking a siesta, and we could hear him snoring. He did wake up and lift his head to look at us, but we gave him plenty of room as we walked past and he returned to his nap.

One of the reasons I wanted to see Franklin Point after the El Niño storms of the past week was to see how much sand had been washed away from the beach. Sand typically accumulates on California coastal beaches during the dry storm-less months of summer and autumn, only to be flushed away by storms the following winter. After a particularly violent storm or a series of storms occurring in a short time, very large amounts of sand can be removed from a beach. For the past four years we haven’t had much of a winter storm season (hence the awful drought) and the beach at Franklin Point has been tall and gently sloped. I’d grown accustomed to this state of affairs, which makes what we saw yesterday qualify as Unusual Thing #3–rocks that had been covered with sand for years and are now exposed.

To set the stage, here’s a picture that I took on an afternoon low tide last year on 17 March 2015:

And here’s yesterday’s photo from the same general area:

Can you see how much steeper the beach is in yesterday’s photo? And those rocks on the left side? They are not visible in the photo from last spring because they were under sand!

Here’s a closer look at the newly exposed rocks:

You can see exactly how high the sand was last summer. What’s really exciting is that these rocks represent pristine habitat that has yet to be exploited. I can look at primary ecological succession this spring! Well, at least until the sand returns and buries the rocks again.

As we meandered among the rocks in the intertidal, Scott and I both noticed an abundance of abalone shells. Fairly early on we spotted this black ab shell lying emersed above the water line:

Turning the shell over we saw Unusual Thing #4–an abalone showing signs of withering syndrome:

We were actually surprised to see that the animal was alive. Healthy living abalone are firmly attached to rocks, tucked into crevices. This one wasn’t attached to anything, just lying on the sand. We picked it up, turned it over, and found the body of the animal shriveled up and filling up only about half of the space it should have occupied. It didn’t respond to gentle pokes but wasn’t dead yet, or at least not dead enough to pass the stink test for deadness.

Withering syndrome is a bacterial disease that inhibits digestive function in abalone. To stave off starvation the infected animal begins to digest its own body tissues. As a result the entire body shrinks and eventually the foot can no longer stick to rocks. In California it affects black abs and red abs (H. rufescens). Until the recent years of warmer-than-usual water black abs (H. cracherodii) had been most common in southern California, but I’ve been seeing more of them in the past few years. Now it looks like the disease that plagues them has accompanied them up the coast. It’s not surprising, given the current El Niño conditions.

This gives me another thing to keep an eye out for in my intertidal excursions. I’ll start keeping track of abalone and see if withering syndrome becomes more prevalent. Might as well start with this afternoon’s low tide!