Skip to content

1

For several weeks now I've been raising another batch of bat star (Patiria miniata) larvae, from a fortuitous spawning that occurred in early January. Since this is rather old hat by now I'm not diligently taking photos or drawing the larvae as often as I would have years ago when this kind of undertaking was new to me. But I still change the water twice a week and look at them on Fridays, and I still have the set-up that attaches my old phone to the microscope so I can take pictures of them.

Last Friday it occurred to me that: (A) my gizmo holds the camera steady over the microscope, so I can take pictures at multiple focal planes within objects under the scope; and (B) I have software that will stitch those many snapshots into a single image. Neat!

So I made this:

Bipinnaria larva of the sea star Patiria miniata, age 44 days
44-day-old larva of the bat star, Patiria miniata
2021-02-19
© Allison J. Gong

This larval stage is called a bipinnaria or a brachiolaria. From top (anterior end) to bottom (posterior end) the larva is about 1 mm long. It swims with the anterior end in front. In some sea stars the bipinnaria grows long arms, at which point we call it a brachiolaria ('brachio' = 'arm' in Greek). Bat stars don't grow long arms, so the distinction between bipinnaria and brachiolaria is much fuzzier.

I took 11 photos of this larva, each one focused on a different horizontal plane, and did a focus merge in my photo processing software. Crossed my fingers as the software did its magic, and then peeked at the result. It worked! When looking through the microscope I have to focus up and down through the body to get an idea of its three-dimensional structure. But if the animal holds still long enough, I can do the focus merge thing and get images like this one.

And that slight halo that you see around the exterior surfaces of the larva? That is not an artifact of the photo taking or processing. That halo is due to the cilia that cover the body. There is a ciliated band, which you can see as the dark gold ribbon that snakes along the lobes of the body, and the other body surfaces are ciliated as well. The ciliated band is what the larva uses to swim through the water. Each photo freezes the ciliary action at the moment it was shot, but stitching several photos together causes the cilia to blur into that pale halo.

Nifty!

Intact shells are a limited resource in the rocky intertidal. Snails, of course, build and live in their shells for the duration of their lives. A snail's body is attached to its shell, so until it dies it is the sole proprietor of the shell. Once the snail dies, though, its shell goes on the market to whoever manages to claim it. Empty shells tend not to hang around for long.

Hermit crabs also live inside snail shells. They are the ones that compete for empty shells to become available. Here in California, at least, the hermit crabs can't kill snails for their shells; they have to wait for a snail to die. And once a shell comes on the market, it will have a taker even if it's not the ideal size for the crab. It's not at all uncommon to see hermit crabs that can fit only their abdomen into the shell, leaving the head and legs exposed and vulnerable. On the other end of the spectrum, many hermit crabs are so small that they can pull into the shell and not be seen by an inquisitive tidepool visitor. Anybody taking a snail shell home as a souvenir—where such takes are allowed, of course—must be certain that there is no tiny hermit crab hiding deep in the depths.

Hermit crab in black turban snail shell
Hermit crab (Pagurus samuelis) in shell of turban snail (Tegula funebralis) at Point Piños
2015-05-09
© Allison J. Gong

From a hermit crab's perspective, the best shell is one that is big enough to retreat into but light enough to be carried around. Snail shells come in a variety of shapes and corresponding internal volumes. Turban snails, with their roughly spherical shape, have a large interior space and are coveted by larger hermit crabs. For example, the grainy hand hermit crab (Pagurus granosimanus) seems to really like both black and brown turban snail shells.

Original inhabitant and builder of the shell:

Brown turban snail partially withdrawn into shell
Brown turban snail (Tegula brunnea) at Pistachio Beach
2021-02-09
© Allison J. Gong

And opportunistic second inhabitant of the same type of shell:

Grainy hand hermit crab in turban snail shell
Grainy hand hermit crab (Pagurus granosimanus) in brown turban snail (Tegula funebralis) shell
2018-06-01
© Allison J. Gong

Other snails are not even remotely spherical. Olivella biplicata, for example, is shaped like the pit of an olive. Unlike Tegula, of which both intertidal species are found in rocky areas, O. biplicata burrows in sand. Note the shape and habitat of this olive snail:

Olive snail
Olive snail (Olivella biplicata) burrowing through sand at Whaler's Cove
2019-11-24
© Allison J. Gong

These olive snails have a smaller internal volume, and thus tend to house smaller hermit crabs. Young individuals of P. granosimanus can be found in olive snail shells, but they quickly outgrow the cramped quarters and need to find a larger home. Smaller hermits such as Pagurus hirsutiusculus, though, are often found in olive shells.

Any hermit crab that finds itself robbed of its snail shell has a short life expectancy. The front end of the hermit resembles the front end of any crab, with the familiar armored legs, claws, eyestalks, and antennae. But the abdomen is soft and unarmored, covered by only a thin cuticle. The abdomen is coiled to follow the coiling of the snail shell, which allows the crab's body to curl around the columella, the central axis around which the shell spirals. In this way the crab can hang onto its snail shell and resist a tug by a would-be predator. A strong enough tug, though, will rip the crab's front end (head + thorax) away from its abdomen. So if you ever find yourself with a hermit crab in hand, do not be tempted to remove it from its shell by yanking it out!

The next time you encounter gastropod shells in the tidepools and want to know whether the inhabitant is a snail or a hermit crab, watch to see how it moves. Hermit crabs scuttle, as crabs do, while snails glide along very slowly. You would also notice a difference as you pick up the shell: snails stick to the rock with their foot, which you will feel as a suction. Hermit crabs don't stick at all, so if the shell comes away easily it likely houses a crab instead of a snail. See? Easy peasy lemon squeezy!

Sometimes even a well-known site can present a surprise. Here's an example. Yesterday I went up to Davenport to scope things out and see how the algae were doing. This is the time of year that they start growing back after the winter senescence. I also took my nature journal along, hoping to find a spot to sit and draw for a while.

The first thing I noticed was the amount of sand on the beach. Strong winter storms usually carve sand off the beaches, making them steeper. And during the calmer months of summer the beaches are flatter and less steep. Yesterday the beach was very thick and flat. It makes trudging across the sand in hip boots much easier!

The accumulation of sand meant that I could walk around the first point. Unless the tide is extremely low, such as we see around the solstices, the water is too deep for that. But yesterday I walked around it, and it wasn't until I got to the other side that it occurred to me that: (1) hey, I walked around the point; and (2) I could do that only because there was so much sand. See, a thick beach with a lot of sand makes a mediocre low tide feel lower because the water isn't as deep as it would be if the beach were thinner. When the tide isn't low enough for me to walk around the point, I have to clamber down a cliff. The cliff height varies depending on how much sand has built up, obviously, but is about head height for me. Getting down usually involves scooting on my butt and hoping my feet land on something that isn't slippery. As with most climbing, up is easier and less scary than down.

It's hard to imagine the amount of sand there was yesterday. Look at this picture.

Flat rock area and sandy area
North of Davenport Landing Beach
2021-02-08
© Allison J. Gong

See how the rocks in the foreground end? Usually that's the edge of the cliff. Yesterday I could have just taken a tiny step off the top of the cliff onto sand. That's over 1.5 meters of sand in that one spot! If the couple in the background were visiting this area for the first time, they'd have no idea of the conditions that made it so easy for them to get out onto the reef.

There was a lot of sand in the channels between rocks, too.

Sand between rocks in the intertidal
Intertidal area north of Davenport Landing Beach
2021-02-08
© Allison J. Gong

Normally those channels are deeper. You can see that some anemones were able to reach to the surface of the sand, but many more are buried, along with any other critters and algae unfortunate enough to be attached to the lower vertical surfaces. And while some of them will either suffocate or be scoured off as the sand washes away, many will survive and be ready to get on with life.

The second surprise of the day was a bright orange object. What I could see of it was about as big as my thumb, and at first I thought it was a nudibranch. Then when I crept closer for a better look, what popped into my head was "snailfish". Which was an odd thing, because I'd never seen a snailfish before. But something about the creature's posture looked somehow familiar.

Orange fish with large head and tail wrapped around the body
Tidepool snailfish (Liparis florae) at Davenport Landing
2021-02-08
© Allison J. Gong

Fortunately I had the presence of mind to take photos before trying to draw this little fish, because this is all I had time to get:

When I spooked the critter it took off really fast, confirming that it was no nudibranch. It was, indeed, a snailfish! It came to rest in a small hole in a rock, from where it looked out at me.

Tidepool snailfish (Liparis florae) at Davenport Landing
2021-02-08
© Allison J. Gong

The snailfishes are a very poorly studied group. As a group they are related to the sculpins. There are snailfishes throughout the northern temperate and polar regions, from the intertidal to the deep sea. iNaturalist shows 43 observations of L. florae, eight of which are in California. Before yesterday, none had been recorded at Davenport Landing.

Map of northeast Pacific coast, showing sighting of tidepool snailfish recoreded in iNaturalist
Observations of tidepool snailfish (Liparis florae) recorded in iNaturalist
2021-02-09
© Allison J. Gong

So there you have it, a snailfish! We don't know much about any of the snailfish species, even the intertidal ones. They apparently have pelvic fins modified to from a sucker, similar to the clingfishes, but I didn't have a chance to examine this specimen closely enough to confirm that. I don't know why they are called snailfishes, either. They're not snail-shaped at all.

Now, about that thing up there where I said "snailfish" came to mind even though I'd never seen one before. That happens quite a bit—a name will jump into my head before I've had a chance to think about it. Sometimes I'm wrong, but often I'm right. I know I hadn't seen a live snailfish before, but obviously I'd seen photos of them or I wouldn't have been able to recognize this orange creature as being one. It's fascinating how the brain forms search images, isn't it?

During what has become my daily check to see what's going on in Younger Lagoon, I got totally lucky and was able to see and photograph lots of birds. A morning with mostly cloudy skies meant good light for picture-taking. So I took lots of pictures! Some of these are series and need to be viewed in order to see the action. Sure, I could have just shot videos, but where's the fun in that? Sometimes still photos show a lot more than video.

It was a great day to watch wading birds! Legs and beaks come in varying lengths, and a particular species' combination of beak length and leg length determine where and how the bird forages.

Long-billed curlews, snowy egret, and marbled godwit on the beach at Younger Lagoon
Shorebirds at Younger Lagoon. Left to right: Two Long-billed curlews (Numenius americanus); snowy egret (Egretta thula); long-billed curlew; marbled godwit (Limosa fedoa)
2021-01-30
© Allison J. Gong

While the long-billed curlew (N. americanus) has the longest beak-length-to-head ratio of any bird, the marbled godwit and whimbrel also have impressively long bills. In the photo below, the three birds with slightly downcurved beaks are whimbrels (Numenius phaeopus) and the one bird with the two-toned straight beak is the godwit (Limosa fedoa). Most of the godwits I've seen have beaks that are a smidge upturned, but this one looks pretty straight to me.

Whimbrels and marbled godwits in the surf zone at Younger Lagoon
Shorebirds at Younger Lagoon. Three whimbrels (Numenius phaeopus) with downcurved beaks and one marbled godwit (Limosa fedoa) with straight beak
2021-01-30
© Allison J. Gong

All of these birds forage by probing the sand with their beaks. All sorts of infaunal invertebrates are taken, and the mole crab Emerita analoga is a favored prey item. Obviously a longer beak allows for deeper probing in the sand, and the variation in beak lengths among the shorebird species may allow for niche partitioning. In other words, a long-billed curlew can reach down for prey items that are unavailable for birds with shorter beaks. The flip side of this equation is that birds with the "short" beaks might be better at picking up prey buried that are buried at shallow depths.

Prey are also distributed patchily along the beach itself, from the surf zone to the dunes, and these birds forage in the entire range. The length of the legs determines how far down into the surf zone they can go. When the beach is steep, as it is now at Younger Lagoon, the birds don't have much time to dig around in the surf zone before the next wave comes up. Click through the slide show to see this group of godwits, curlews, whimbrels, and a snowy egret react to an oncoming wave. It's important to note that while these birds do have some waterproofing in their feathers, they do not swim. Nor can they take flight if their feet aren't on the ground. Getting swept up by a wave and carried off the beach would likely be deadly for them.

The long-billed curlew is a favorite of mine, because I can't imagine what it would be like to go through life with a 2-meter beak sticking out of my face. They are fun to watch, and can probe remarkably fast with that long beak. This is one of the phenomena that is best shown by video.

You can watch how the birds forage within the surf zone, as in the slide show above, and also how long-billed curlews probe the sand higher up the beach.

Shorebirds foraging at Younger Lagoon
2021-01-30
© Allison J. Gong

These long-legged wading birds also feed in protected bodies of water and estuaries. All of these species can be seen at Elkhorn Slough as well as on the open coast, as one would expect from the Slough's position along the Pacific Flyway. Some birds migrate to California from far away. Marbled godwits, for example, spend the summer breeding season in the interior regions of North America, and winter along the Pacific, Gulf of Mexico, and Atlantic coasts. The long-billed curlew also breeds in the interior of the continent. Snowy egrets, on the other hand, are year-round residents.

I am grateful to have access to places like Younger Lagoon, where I can spend time outdoors without other people around, remove my mask, and take pictures of birds. I love that the Younger Lagoon Reserve has so many different habitats to explore, from ocean to beach to dunes to coastal scrub, in a small area. Fingers crossed that sooner rather than later, we'll be able to once again bring students there to study the natural world in the Reserve's outdoor classrooms.

In terms of weather, this has been the first real week of winter we've had so far this season. But finally we're getting some action from an atmospheric river, and it is bringing both much-needed rain and the threat of mudslides in mountain regions that were badly burnt just a few months ago.

Graphic showing what atmospheric rivers are and how they affect precipitation

During an El Niño event, the probability of higher-than-average rainfall in California is usually due to what are called Pineapple Express storms. These warm, wet storms occur when the atmospheric river is to the south and picks up and transports water from the tropics. La Niña, which is the counterpart to El Niño, typically results in drier-than-average conditions in California, but when the atmospheric river does come into play it comes from the north and is cold.

We are currently at the mercy of La Niña, and weather forecasters predict these conditions will continue through February and then begin to wane through the early spring. This means that the storms we've had over the past several days have been cold. According to our weather station, on Monday 18 January the high temperature was 24ºC (75ºF), and a week later on Monday 25 January the high was 12ºC (53ºF). It has continued to be chilly throughout the week. Today, Friday 29 January, we're getting a break between storm systems and it's beautifully sunny. Because of the sun it feels warmer, but the actual air temperature probably won't get much higher than it has been already this week.

Yesterday we were hit by what was probably the strongest of the storms in this particular atmospheric river. At the marine lab the waves were routinely splashing up and over the cliffs. When that much water crashes into solid land, the pounding is felt as much as it is heard. After doing my chores I wandered over to Younger Lagoon to see what was going on. I wanted to see if the lagoon had broken through the sand bar.

I spent some time watching the ocean, and this is what I saw:

Storm waves at Younger Lagoon
2021-01-28

That sand bar forms as sand accumulates on the beach during the summer, following the typical sand cycle along the California coast. Younger Lagoon does not drain a river, so there is not a constant flow of fresh water down to the ocean. There is some run-off from the surrounding agriculture fields, but the vast majority of water flowing through the lagoon is run-off from rain. It's that heavy flow of fresh water that sometimes breaches the sand bar and allows water from the ocean to mix with water in the lagoon.

Given how much rain we'd had, I thought it likely that the lagoon would have breached. But as you can see from the video above, it had not. Clearly, there hasn't yet been enough fresh water flow through the lagoon to break through the sandbar.

So we're still waiting for that event. I suspect that once it does, we'll know because of the smell.

In the meantime, the ocean continued to pound the coast. I was wearing my foul weather gear so I went to Natural Bridges to watch the waves slam against the rock formations. That was a fun excursion! The big swells were coming in so fast that the deep BOOM-BOOM-BOOM was almost continuous. Close to shore the water was a constant froth of movement.

Storm waves at Natural Bridges
2021-01-28

You can see how high the waves were hitting against the cliff. The mist blew quite far across the parking lot, and I went home with saltwater drying in my hair. Fortunately I got to spend the rest of the day indoors, drinking tea and keeping dry. Winter storms are great fun, as long as you don't have to be out in them!

According to my notes at the lab, the last time I spawned urchins was December of 2016, making it four years ago. It has always been something I enjoyed doing, but I didn't have a reason to until now.

When the coronavirus pandemic began almost a year ago now, access to all facilities at the marine lab was restricted to a group of people deemed essential. In my case, "essential" had to do with the fact that I keep animals alive. There were many hoops to jump through and inane questions to answer—for example, "What will happen if you don't go in to check on water and food?" and "How many animals will die if you do not have access to the lab, and how much effort [i.e., $$$] would it take to replace them?"—but in the end someone higher up in the food chain exercised some common sense and decided to let me have continuous access to the lab. So I've been at the lab pretty much every day, to check on things and make sure that air and water are flowing.

So over the summer we were running sort of bare-bones operations at the lab. There were many fewer people looking after everyday things. The autoclave broke and wasn't fixed until September. One of the casualties of this less-than-normal vigilance was one of the cultures in the phytoplankton lab. Our Rhodomonas flasks had been contaminated since late 2019, and we were struggling to rescue them. I tried so hard to keep them going ahead of the contamination, but ultimately failed. As of this writing all of the old Rhodomonas cultures have died.

In October, after the autoclave had been repaired, I decided to take action and replace our inevitably doomed Rhodomonas cultures. I found a company that sells small aliquots of many marine microalgae and ordered a strain of Rhodomonas that was isolated in Pacific Grove. May as well see if a local strain of algae works as a food for local larvae, right? The new Rhodomonas cultures seem to be growing well and it's time to see of urchin larvae will eat and thrive on it.

Equipment and glassware used to spawn sea urchins

About a month ago I collected 10 urchins to spawn. Yesterday was their lucky day! Purple sea urchins (Strongylocentrotus purpuratus) are broadcast spawners, and spawning is both inducible and synchronous. We can take advantage of the inducibility to make them spawn when we want, as long as they have ripe gonads. The difficulty is that we can't tell by looking whether or not an urchin is gravid, so all we can do is try to induce them and then hope for the best.

As I've written before, we induce spawning in sea urchins by injecting them with a solution of potassium chloride (KCl). KCl is a salt solution that causes an urchin's gonopores to open and release gametes if the gonads are ripe. I shot up 10 urchins yesterday, and eight of them spawned. An 80% spawning rate isn't bad, but only two of the eight were female and neither of them had a lot of eggs to give.

Since the gonopores are located on the aboral (top) of the urchin, the easiest way to collect eggs is to invert the animal on a beaker of seawater, like so:

Female sea urchin (Strongylocentrotus purpuratus) spawning
2021-01-12
© Allison J. Gong

In nature the eggs, which are a pale orange color, would be whisked away by currents to be (hopefully) fertilized in the water column. In the lab we can collect the eggs in the beaker, as follows:

This is much less damaging to the animal than trying to pipet eggs off the top of the urchin.

We try to collect sperm and keep it dry, so there is no putting males upside-down on beakers of water. Instead we pipet up the sperm and keep it dry in dishes on ice. When it's time to fertilize the eggs we dilute the sperm with filtered seawater and add a small amount to the eggs.

One of my favorite things ever is watching fertilization take place in real time, under the microscope. It truly is one of nature's most amazing phenomena. It is a great thrill to watch the creation of new beings.

In the video you see eggs being bombarded with sperm, probably at much higher concentrations than they would encounter in the wild. It is common knowledge that it takes only one sperm to fertilize an egg, but what would happen if two sperm penetrated an egg at the same time? I've written about polyspermy and the fast and slow blocks thereto, in case you'd like to refresh your memory about what is happening in the video.

A successfully fertilized egg is easily recognized by its fertilization envelope, which is the slow block to polyspermy.

Zygotes of the purple sea urchin (Strongylocentrotus purpuratus)
2021-01-12
© Allison J. Gong

After fertilization, the next step to watch for is the first cleavage division, which occurs about two hours later.

2-cell embryos of the purple sea urchin (Strongylocentrotus purpuratus)
2021-01-12
© Allison J. Gong

Aren't they pretty?

Over the next day or so the cleavage divisions continue, resulting in the stage that hatches out of the fertilization envelope. This stage is a blastula, which is a hollow ball of ciliated cells. The hollow space inside is called the blastocoel, and it is here that the larval gut will soon develop.

Blastula of the purple sea urchin (Strongylocentrotus purpuratus)
2021-01-12
© Allison J. Gong

It's easier to see the 3-dimensional structure of the blastula by watching it spin around.

As the blastula rotates under the coverslip, you can see the ciliary currents that would propel it through the water. You also see some objects that look like sperm and are, in fact, dead sperm, getting caught up in the currents.

The blastula is the same size as the egg. The embryo can't begin to grow until it eats, which won't happen until it has a gut. Over the next few days an invagination will begin at a certain location on the blastula which is called the blastopore; this invagination will eventually form the first larval gut. At that point I will have to start feeding them and calling them larvae.

And just to remind you of our humble beginnings, we begin life in much the same way as sea urchins. That blastopore, or initial opening to the larval gut, is the anus. The mouth doesn't exist until the invagination breaks through to the opposite end of the embryo. So yes, like the sea urchin, you had an anus before you had a mouth!

4

On the penultimate day of 2020 I met up with my goddaughter, Katherine, and her family up at Pigeon Point to have two adventures. The first one was to find a marble that had been hidden a part of a game. We got skunked on that one, although the marble was found after we left and the hider had sent an additional clue. The second adventure was an excursion to the tidepools. I've had a lackadaisical attitude towards the afternoon low tides this winter, not feeling enthusiastic about heading out with all of the people and the wind and having to fight darkness. But the invitation to join the marble hunt, on a day with a decent low tide, meant that I could spend a good deal of quality time with Katherine.

It is not unusual for a promising low tide to be cancelled out by a big swell. It happens, especially during winter's combination of afternoon lows and occasional storms. The swell yesterday was pretty big.

Here's the view to the north, from Pigeon Point:

Looking north from Pigeon Point
View to the north from Pigeon Point
2020-12-30
©Allison J. Gong

All that whitewash breaking over the rocks is not good for tidepooling, especially with small kids in tow.

This is how things looked to the south of the point:

View to the south from Pigeon Point
2020-12-30
©Allison J. Gong

This is Whaler's Cove, a sandy beach that lies on the leeward side of the point itself. See how the water is much calmer? It's amazing how different the two sides of the point are, in terms of hydrography, wind, and biota. The south side is much easier to get to, especially for newbies or people who are less steady on their feet. Being sheltered from the brunt of the prevailing southbound current means that the biological diversity is, shall we say, a bit subdued when compared to what we see on the north side of the point.

I first took Katherine tidepooling when her sister, Lizzie, was an infant riding in her mom's backpack. Katherine was about four at the time. Her mom and I were suprised at how much she remembered. She recognized the anemones right away, even the closed up cloning anemones (Anthopleura elegantissima) on the high rocks. She remembered to avoid stepping on them—that's my girl!

She wasn't all that keen on touching the anemones, though, even after we told her it feels like touching tape.

Giant green anemone in tidepool
Giant green anemone (Anthopleura xanthogrammica)
2020-12-30
©Allison J. Gong

She did like the sea stars, too. Purple is my favorite color and I think hers, too, so the purple and orange ochre stars were a hit. It was nice to see two large healthy ones.

I had some actual collecting to do, so it was a work trip for me. Late December is not the best time to collect algae, but I wanted to bring some edible seaweeds back to the lab to feed animals. We haven't had any kelp brought in since the late summer, and urchins are very hungry. They will eat intertidal seaweeds, though, and when I go out to the tidepools I bring back what I can. It will be a couple of months until we see the algae growing towards their summer lushness, but even a few handfuls of sea lettuce will be welcome to hungry mouths.

Bright green sea lettuce growing with red algae
Sea lettuce (Ulva sp.)
2020-12-30
©Allison J. Gong

Katherine and I walked up the beach for a little way to study one of the several large-ish crab corpses on the sand. This one was a molt rather than an actual corpse.

Rock crab molt on sand
Rock crab (Romaleon antennarium) molt
2020-12-30
©Allison J. Gong

Katherine found the missing leg a little way off, and we discussed why we call these limbs legs instead of arms. "They use their claws to pinch things, like hands," she said. Not wanting to get into a discussion of serial homology and crustacean evolution with a 6-year-old, I told her that calling the claws "hands" isn't a bad idea, since they are used a lot like the way we use our hands. But, I continued, the crab walks on its other limbs like we walk with our legs, so can we call those legs? She was happy to agree with that. I can tell I will have to be careful about how I explain things to her, so that she doesn't come up with some wonky ideas about how evolution works.

In the meantime, Lizzie, the little sister, was having a grand old time. She flooded her little boots without a complaint and, after her mom emptied the water from them, squelched happily along with soggy socks. That girl may very well grow up to be a marine biologist!

Once the sun went behind the cliff it started getting cold. With one child already wet we decided to head back. On our way up the beach we saw this thing, which I pointed out to Katherine:

"What is it?" she asked. When I asked what she thought it was she cocked her head to one said and said, "It looks like a rock." Then I told her to touch it, which she didn't want to do. So I picked it up and turned it over, to show her the underside:

Gumboot chiton (Cryptochiton stelleri)
2020-12-30
©Allison J. Gong

These big gumboot chitons do look more interesting from this side, because you can at least see that they are probably some kind of animal. Katherine had seen some smaller chitons on the rocks, so she had some idea of what a chiton is, but these are so big that they don't look anything like the ones we showed her earlier. Plus, with their shell plates being covered with a tough piece of skin and invisible, there are no outward signs that this bizarre thing is indeed a chiton. Katherine was not impressed.

At this time of year, when the sun decides to go down it goes down fast. But as we were walking back across the rocks the tide was at its lowest, so there was more terrain to explore. Then it was back up the stairs to the cars, where we could get warm and dry.

Beach and lighthouse at Pigeon Point

Oh, and Katherine and her mom and sister were able to find the hidden marble! They also hid one of their own for someone else to find.

At the end of August I got to play animal wrangler for a film production. Back in the late winter I had been contacted by an intern at KQED in San Francisco, who wanted to shoot some time-lapse footage of anemones dividing. We went out and collected anemones, I got them set up in tanks at the marine lab, and then COVID19 hit and everything went on shut-down. The intern finished her internship remotely and went on to her next position, and in the meantime the anemones stubbornly refused to divide.

The KQED lead videographer for the Deep Look video series, Josh Cassidy, who would had recorded the anemones dividing if they had divided and if the marine lab were not closed, asked me over the summer if we could somehow arrange to meet up to film something else. He had heard of some research that showed the emergent property of sea stars bouncing as they walk along on their many tube feet. Is there any way, he asked, that he could film some of the stars at the lab?

Well, filming at the lab was out of the question. Only essential personnel are allowed in the buildings, and there was no way I could sneak in Josh and all of his gear. We discussed options such as meeting up at a beach but I decided that I needed more control of the site to keep things safe for the animals. We ended up borrowing some friends' back yard for the day, which worked out pretty well. They have a covered pavilion, which was ideal because of course it turned out to be hot the day we filmed. I had several bags of frozen seawater to keep things cool-ish, two coolers for the movie stars themselves, a battery-operated air pump, and 30 gallons of seawater on hand.

Filming for production purposes takes a really long time. Even for a short film, we were working most of the day. Because of course most of the stars were uncooperative. They don't have anything even remotely resembling a brain, but damn if they can't bugger things up. I was feeling kind of bad that my animals were being such troublemakers; Josh, fortunately, was much more patient with them.

And here's the film! You'll see my right hand for about 1.5 seconds.

I didn't realize this at the time, but Josh also writes an article for each episode of Deep Look, for the KQED website. For this episode the article describes the research into the biomechanics of sea star bouncing. I'm quoted at the end.

So watch this short film. I hope it helps put a little bounce in your step.

Still more or less under quarantine shutdown due to COVID19, I haven't been doing much outdoor stuff over the past several months. What with the pandemic and horrid air quality due to wildfires throughout the state, spending time in places I would normally like to hang out simply hasn't been possible. We're still getting too many out-of-the-area visitors for me to feel comfortable being around people, and weekends are especially bad. But last weekend I went to Moss Landing to take pictures of birds and other wildlife—I needed visual aids for a virtual lab my students will be doing in a few weeks.

It's the time of year for birdwatchers to get excited about winter visitors. I've had golden-crowned sparrows in the canyon behind the house for almost a month now, but I hadn't been down to a beach in a while. Moss Landing is a great place for birdwatching, because you can explore the estuarine habitat of Elkhorn Slough, the sandy beach, and the harbor during a 2-mile walk. That's three distinct habitats for very little effort!

Starting at the tidal marsh, I always keep an eye out for the long-billed curlew (Numenius americanus). They have the largest beak-to-head ratio of any bird.

Long-billed curlew (Numenius americanus) in salt marsh
Long-billed curlew (Numenius americanus)
2020-10-10
© Allison J. Gong

One of my favorite winter visitors to the marsh area is the willet (Tringa semipalmata). Unlike most shorebirds that are speckled or mottled, willets in winter plumage are a beautiful soft gray-ish brown color. Every time I see a willet I ask myself, "Willet, or won't it?"

Willets in marsh at low tide
Willets (Tringa semipalmata)
2020-10-10
© Allison J. Gong

And when they take off in flight, willets show these striking black and white wing patterns. They always take me by surprise, even though I know to expect it.

Willet in flight, showing white flashes on wings
Willet (Tringa semipalmata) in flight
2020-10-10
© Allison J. Gong

A whole flock of willets taking off at once is quite an impressive sight!

Flock of willets in flight
Willets (Tringa semipalmata) in flight
2018-11-14
© Allison J. Gong

From the marsh it's a short walk over the dune and onto the beach.

I always look forward to walking this beach because of the dead things. Don't get me wrong, the living things are fun to see, but in some ways the dead critters can be more informative. For every species there is always some baseline level of mortality in the ocean, so you expect a certain number of dead things to wash up. However, an unusually high number of corpses could indicate that something is going on at sea. This trip I didn't see very many dead critters: just a few grebes that had been there for a while, nothing out of the ordinary.

Oh, and an otter pup. At least, I'm pretty certain it was an otter.

Yes, we came across a dead sea otter pup, my first ever.

Dead sea otter pup on the beach
Dead southern sea otter (Enhydra lutris nereis) on the beach
2020-10-10
© Allison J. Gong

The body was missing a head, but the parts that remain were a bit longer than my booted foot. Although most of the soft tissue had been scavenged, the carcass had distinct paws, meaning it wasn't any kind of pinniped (seal or sea lion). Also, pinnipeds don't have fur like this, as they rely on blubber for thermoregulation. Sea otters, on the other hand, have the densest fur of all mammals, with the oft-cited 1 million hairs/in2.

But let's be honest. I like the beach because I like photographing birds, and there is always interesting bird life at this beach. I'm not one of the crazy bird people who keep a life list and need to be the first person to spot a particular something-or-other. And, unlike the idiots I saw tramping through the pickleweed in pursuit of a Say's phoebe that day, I don't climb over fences and trespass where I'm not supposed to be. Besides, even the everyday backyard birds are fun to watch. Whoever says that familiarity breeds contempt certainly is not a naturalist!

And who doesn't love a snowy plover or two?

Snowy plovers (Charadrius nivosus)
2020-10-10
© Allison J. Gong

The snowies aren't nesting at this time of year so the upper part of the beach isn't roped off. They do still get disturbed by people wandering around, who probably don't even know the birds are there. They (the snowies, that is) are so tiny that when they hunker down behind a divot in the sand they disappear completely. If you sit or stand quietly, they will pop up and make short dashes from hillock to pile of beach wrack and back again, feeding on the insects and crustaceans they find.

In addition to the snowy plovers, another tiny "peep" bird runs around on the beaches, often in large groups. These are the sanderlings, Calidris alba. I've only ever seen them in nonbreeding plumage, as they nest in the high Arctic.

Sanderlings (Calidris alba)
2020-10-10
© Allison J. Gong

Sanderlings are the little birds that run back and forth from the waves. As a wave recedes the sanderlings frantically stab their stout beaks into the sand, grabbing up small mole crabs and other crustaceans that are right at the surface. When the next wave arrives the sanderlings run back up the beach. They have short legs and don't swim, so getting swept out to sea would be a very bad thing for them.

Sometimes even the long-legged shorebirds forage on the beach. I've seen the curlew there, as well as whimbrels and godwits. This day the godwits were stealing the show.

Marbled godwits (Limosa fedoa)
2020-10-10
© Allison J. Gong

The godwits, with their longer legs, are able to stand their ground when the waves wash up. They can catch food that is buried more deeply into the sand. On mudflats they pick their way over the flat at low tide, digging for worms, clams, and crustaceans. They can feed on a mudflat only at low tide. But on the beach they can feed at any time, just moving with the tide as it floods and ebbs.

And my friend the long-billed curlew was there on the beach, too!

Long-billed curlew (Numenius americanus)
2020-10-10
©Allison J. Gong

The curlews are not as eager to forage in the waves themselves as the godwits seem to be. The curlews might wander down to where their ankles are swashed by the waves, but do not seem to like getting wetter than that. But that bill can probe very deeply into the sand or mud. I've watched them feeding on mole crabs on the beach, and on worms on the mudflats.

Autumn and winter are good times to watch birds around here. There's a bit of a lull in bird activity once the swallows leave depart for the south and before the winter residents show up. For me, autumn begins when the golden-crowned sparrows arrive in the neighborhood, which this year was September 25. I'm listening to them now as I write this! Being located on the Pacific Flyway means we get lots of birds resting for a bit on their migration even if they don't winter here. I'll try to get out to Moss Landing during the winter months, to keep track of the avian comings and going.

In this strange pandemic school year with classes online and student clubs not able to meet in person, the Natural History Club has been meeting virtually twice a week. We can't go out as a group on any field trips, so the students have been sharing their nature journals online. Yesterday we played Jeopardy! I didn't win, but I didn't embarrass myself, either.

Last spring I was scheduled to give a tidepool talk as an event for the club. The talk was scheduled for mid-March, exactly the time when COVID19 arrived and threw all plans into the blender. The good news is I get to give the talk virtually next month, as the first event of the year. Please come!

Here's the link to register for the Zoom meeting: https://cccconfer.zoom.us/meeting/register/tJ0tc-ChpjMrHdVEvjcsu3v31IjD1M3lK8aI

%d bloggers like this: