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Published on Leave a comment on Hungry? Then just keep swimming

Yesterday I had some time to kill before getting a COVID test, and, as usual, wandered down to the ocean. This time I was at Seacliff State Beach. It was pretty crowded, so I walked onto the pier to see if the fishermen were having any luck. They weren't, really. One man kept catching jack silversides (Atherinopsis californiensis) that were too small to keep. There was a lot of banter about sharks and bait and crabs, but what I witnessed yesterday confirms my hypothesis that a lot of what people call "fishing" is merely an excuse to get outside for a few hours. And there is absolutely nothing wrong with that.

As for me, I have nowhere near enough patience to make a decent fisherman. I did, however keep myself amused by eavesdropping on their conversations and writing snippets in my nature journal. I did also find myself mesmerized by the anchovies. Watch for yourself.

Northern anchovies (Engraulis mordax) at Seacliff State Beach
2021-11-23
© Allison J. Gong

Like sardines, anchovies are planktivorous filter feeders. If you watch the video again and can focus on an individual fish for a while, you'll see that as it swims forward, the front end becomes white and bulbous for a few seconds. That's sunlight reflecting off the fish's jaws. Anchovies have metallic silver coloring, which is a defense against predators. For fish that live in surface waters that are brightly lit, all of those glinting flashes of light make it difficult for a predator to zero in on a single fish to pursue. There is safety in numbers, and for anchovies the silvery coloring combined with schooling behavior means that if a predator manages to catch some of the fish in the baitball, most will avoid being eaten. This works against predators such as larger fish, squid, and birds, which generally capture one or a few fish at a time. But if the predator happens to be a humpback whale, which is capable of engulfing the entire school, then the anchovies are SOL. Think about it, though. For any anchovy, the probability of encountering a larger fish, squid, or bird is much higher than encountering a humpback or blue whale. Thus the selective advantage of schooling!

Okay, now back to the feeding. Anchovies have really long jaws for their size and can, like snakes, open their mouths very wide. This allows them to filter as much water as possible as they swim. Food, mostly plankton, is caught on the gill rakers, which are bony or cartilaginous structures projecting forward (i.e., towards the mouth) from the gill arches. Some fishes' gill rakers are nothing more than short nubs. Filter feeding fishes such as anchovies have long thin gill rakers. Water enters the mouth as the fish swims forward, and plankton is caught on the array of gill rakers. The water then passes over the gill filaments, where respiratory exchange occurs, and then out from underneath the operculum. Anchovies cannot suck water into their mouths, and thus can feed only while swimming forward, or ramming water into the mouth. This is a type of feeding called ram feeding.

These anchovies were very close to shore. They were feeding, so obviously there was plankton in the water. I haven't done a plankton tow in a while, as I generally assume that fall/winter plankton isn't as interesting as spring/summer plankton. However, given the presence of feeding anchovies inshore, it might be time to test that assumption.

Published on Leave a comment on Butterflies

I go to Natural Bridges quite often, to play in and study the rocky intertidal. But at this time of year, before the low tides really get useful, there is another reason to visit Natural Bridges—to see the monarch butterflies (Danaus plexippus). Natural Bridges State Park is a butterfly sanctuary, providing a safe overwintering spot for migrating monarchs.

Yesterday morning, while it was still cool enough for the butterflies to be hanging in clusters, I went out and photographed them. Last year's count was only 550 for the winter, but I'd heard that there were more butterflies this year and it was definitely worthwhile going out and looking for them.

Monarch butterflies clustered in eucalyptus tree
Monarch butterflies (Danaus plexippus) at Natural Bridges State Park
2021-11-06
© Allison J. Gong

The butterflies rest with their wings up, so when they are hanging like this you see the duller underside of the wings. A few of them were starting to warm up their flight muscles and showing off the more brilliant orange of the dorsal wing surface.

Monarch butterflies clustered in eucalyptus tree
Monarch butterflies (Danaus plexippus) at Natural Bridges State Park
2021-11-06
© Allison J. Gong
Monarch butterflies clustered in eucalyptus tree
Monarch butterflies (Danaus plexippus) at Natural Bridges State Park
2021-11-06
© Allison J. Gong

I am really not good at counting things like this, but my guess is that there were hundreds of butterflies, all told. Based on the 2020 season, when I didn't see any monarchs at all at my house and only a few scattered individuals at Natural Bridges, this year's population seems to be doing much better. 2020 was an awful year in California in general, and in the Santa Cruz region in particular. The CZU August Lightning Complex fire put air quality into the unhealthy-for-everybody range for several weeks. Much of the rest of the western U.S. also burned, with much habitat loss for nature. Maybe that's part of why there were so few monarchs last winter in Santa Cruz. Of course, the monarchs' populations have been declining for years, so last year's population crash may be only a dip in the grand scheme of things.

Whatever the cause, it really was good to see even this many butterflies at Natural Bridges.

Oh, and before starting my butterfly hunt in earnest, I spent about an hour watching and listening for birds. I wanted to get the birdwatching in before human activity drowned out the birdsong. Unfortunately, most of what there was to hear was the cawing of crows.

Nature journal page of birds seen and heard
Page from my nature journal

Next time I'm at Natural Bridges, I'll try to remember to check in with the visitor center to see what the official count for monarchs is. Fingers crossed the number is a lot higher than 550!

Published on Leave a comment on A promising start

Over the weekend the atmospheric river slammed into Northern California and settled over us for a few days. Our weather station at home, roughly at sea level, measured 4.5 inches of rain. On Sunday afternoon it was extremely windy, and I think the rain wasn't falling vertically enough to be captured by the rain gauge, and my guess is that another half-inch or so fell but wasn't measured. A total of about 5 inches of rain feels right.

This storm was a very big deal for us, for a couple of reasons. The most obvious is that California is in the midst of another severe drought. There wasn't much rain or snowfall at all in the 2020-2021 rain season, reservoirs are drier than I remember seeing them, and the governor has asked residents to reduce water consumption statewide by 15%. We are woefully short of that conservation mark. So yeah, the amount of water available to all consumers is (or should be) of concern to all of us.

A second reason why we all paid so much attention to this storm was the fact that much of the rain was forecast to fall on areas that had burnt recently, including the 2020 CZU Lightning Complex fire burn scar. Both the 2020 and 2021 fire seasons were horrendous, leaving many acres of previously forested land bare and prone to mudslides, or "debris flows" in modern parlance. Residents in the Santa Cruz Mountains were warned to prepare for evacuation, just in case. And everyone was prepared to deal with power outages, which, oddly enough, didn't happen.

On Friday the 22nd, before the major storm blew in, I went to Younger Lagoon to record some video clips for my Marine Biology class. One smaller storm had already blown through and it was very windy. I encountered two birders who were looking for pelagic birds that had been swept into the lagoon or were seeking shelter from the elements.

This is what the lagoon looked like on Friday:

North end of Younger Lagoon
Younger Lagoon
2021-10-22
© Allison J. Gong

In fact, here's the video I put together for the students:

So that was Friday. On Saturday we went hiking at Moore Creek Preserve with our god-daughter and family. We all wanted some quality outdoors time before the major storm event on Sunday/Monday.

Yesterday (Monday) I went back to Younger Lagoon to see how much it had changed with all the rainfall. I could tell from the smell that the sand berm hadn't been breached yet. We can always tell when the lagoon breaks through, because all of the hydrogen sulfide buried in the sediment gets into the air. It's a smell that, once known, is difficult to forget. Anyway, I took a photo of the top of the lagoon from the same spot as on Friday. And see how much difference one big rain event can make:

Younger Lagoon
2021-10-25
© Allison J. Gong

To make the comparison easier, let's look at those photos side-by-side:

  • 2021-10-22
  • 2021-10-25
Younger Lagoon before (left) and after (right) the bomb cyclone storm of 2021-10-24

We had a high surf advisory yesterday, so I wandered down into Younger Lagoon to check out the ocean conditions. I could hear that the surf was really big. It was still windy, too.

Just to make sure my intuition was correct, I stopped to check out the sand berm. And yes, it was still there.

Sand berm between the Pacific Ocean and Younger Lagoon
2021-10-25
© Allison J. Gong

The waves were big and the sets were coming in fast. I shot this video at about low tide yesterday morning. We're in neap tides right now so the low wasn't very low.

High surf advisory at Younger Lagoon
2021-10-25
© Allison J. Gong

Storms and tidal surge, when combined, can wreak havoc on nearshore coastal habitats. One of the obvious victims of the recent violence is the kelp bed. The kelps have been on their seasonal decline for weeks now, and the storm-strengthened swell tore up a lot of kelp and deposited it on the beach. Thousands of detached pneumatocysts (floats) of Macrocystis pyrifera had been blown into windrows. The lighter colored pneumatocysts are the ones that were washed up earlier, probably in the second-most-recent high tide; the darker ones were deposited during the most recent high tide, about six hours earlier.

Kelp debris, mostly Macrocystis pyrifera, on the beach at Younger Lagoon
2021-10-25
© Allison J. Gong

I expected to see dead animals on the beach, too, and was surprised that there weren't any carcasses in sight. Then I looked across the beach with binoculars and saw a couple of turkey vultures (Cathartes aura) on the sand, and a third on the fence above. Vultures eat carrion, so there must be a corpse over there after all. Sure enough, there was a dead bird. As I approached I saw a black body with a smaller reddish part, and my first thought was, "Are turkey vultures cannibals? Will they eat their own dead?" because turkey vultures have unfeathered red heads. But when I got closer I could see that this corpse had webbed feet. It was, in fact, a cormorant.

Dead cormorant at Younger Lagoon
2021-10-25
© Allison J. Gong

The scavenging turkey vultures flew away as I approached. I didn't want to interrupt their brunch any longer than necessary, so stuck around just long enough to snap a few photos. By the time I had crossed back to the near side of the beach, they had returned to their feeding.

All told, this storm was a good start to the rain season. It put an end to the fire season, which is a huge relief to all of us living in California. We have a long way to go to return to normal rain levels, whatever they are in this era of anthropogenic climate change, and it irks me to hear people saying that we've had a lot of rain now, so the drought must be over. Too bad it doesn't work that way, or we would all be rejoicing big time.

Climate change models predict, among other things, oscillation between extreme rain events and extreme drought in California. Just in the past handful of years we've had drought plus the Blob (2015), a wet winter in 2016-2017, and a return to dry conditions from 2018-2020. And we all remember the extreme fire seasons of 2020 and 2021. So what is "normal" these days? I think it's impossible to know. We are experiencing climate change as it happens, and we don't know how or when things will begin to stabilize. I suspect it won't be within the lifetime of anyone reading this blog.

Still, after having about zilch in the way of rain last year, it's good to see that Mother Nature can still throw an atmospheric river at us. Fingers crossed for more rain as the season continues.

Published on Leave a comment on Practice, practice, practice

Over the weekend we had dinner with some family members down in Monterey, and my niece gave me a leaf. She had collected it somewhere and carried it around for a while, and I never did get a clear answer about where it came from. To me it looks like a magnolia leaf. When I said it looked like a fun leaf to paint, she told me I could take it home.

December's leaf

The next day I sat at my desk and studied the leaf for a while. And, as most things do, the leaf became more complicated the longer I looked at it. The shape wouldn't be difficult to get on paper, but I wanted to work with the colors. I always think that getting the right color is easier with colored pencils than watercolors, so I started with what I assumed would be the greater challenge.

As anticipated, I had real difficulties with the highlights. I still haven't figured out how to paint shine. And in retrospect it might have been better to paint wet-on-wet instead of letting the paint dry before adding more color.

And that shape, which I thought would be a slam-dunk? I was so wrong about that! The paper in my sketchbook isn't heavy watercolor paper at all, and with all the erasing I had to do to get that foreground curve right I was afraid I'd remove too much of the texture. I like the overall effect, and I did kind of get the perspective right, which is always hard for me. I stopped before experimenting more with the bright highlights because I didn't want to overwork this sketch. I still don't know what to do about those.

Now, onto the pencil version.

As I noted in the sketchbook, what I thought would be easier ended up being not. I do like the color rendition here, and I think the toned paper works well. And as an aside, the Prismacolor Black Grape pencil does make pretty shadows. In this sketch I positioned the highlights with too much symmetry, and as a result this leaf looks like a feather. It might look better if I made the veins more visible. I can still do that.

Looking at both of these sketches, I think I like the watercolor version better. What do you think?

Published on Leave a comment on Hoppenings at the beach

Over the past couple of weeks I've rented two super telephoto lenses, to see what all the hype was about. I mean, do I really need 500 or 600mm of reach? I had read up on the specs of such lenses, and one major drawback is the weight—1900 grams or more. Would I be willing to lug a beast like this around, and would I be able to use it effectively? You never know until you try, so I rented them. And, of course, it was foggy both weeks so I didn't have much opportunity to take decent photos. But since the entire point of renting the lenses was to see if I could use them at all, that was fine.

As part of the test-drive for the second lens, I went up to Waddell Beach to see if there would be any birds to photograph. It is migration season, and our winter residents will be arriving soon. Some of them, such as the red-necked phalarope, have shown up at Younger Lagoon over the past four weeks or so. It was really foggy at Waddell, remember, and I didn't have much hope of seeing anything remarkable. There were some gulls and whimbrels off in the distance. But it turned out that the stars of the show were blackbirds!

They were hard to miss, because there were 50-60 of them and they were hopping up and down like jumping beans.

This is a mixed flock of Brewer's blackbirds (Euphagus cyanocephalus) and red-winged blackbirds (Agelaius phoenicius). The glossy greenish-black birds are the male Brewer's blackbirds, and most of the brownish birds are female Brewer's blackbirds. Since both sexes were doing the hopping, I didn't think this behavior had to do with courtship or mating.

So yes, while most of the birds seemed to be Brewer's blackbirds, I did hear the liquid gurgling of the red-winged blackbird's song coming from somewhere in the flock. When I got home and looked at the photos on the big monitor, I did see some red-winged blackbirds. Here's a male, surrounded by other males red-wingeds and both female and male Brewer's blackbirds.

Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong

In this photo above the black birds are male Brewer's blackbirds. The brown birds without faint wing bars are female Brewer's blackbirds, and the brown birds with the wing bars are male red-wingeds. There were no female red-winged blackbirds in any of my photos. According to an article from Cornell's Bird Academy, the males spend the weeks leading up to springtime competing for territories, and when the females return from their winter migration they will choose mates based partly on the quality of the territory. Mid-September is too early for this kind of competition, though. We are just about up to the autumn equinox, but not near winter quite yet.

Back to the hopping. There's a clue in this photo about what I think was going on:

Male Brewer's blackbird (Euphagus cyanocephalus) at Waddell Beach
2021-09-14
© Allison J. Gong

See that little fly? There were many such flies, most of which were lower on the beach gathering around the kelps and other wet detritus that had washed up. There were fewer flies up where the driftwood accumulates, though. Once again, it wasn't until I saw the pictures on my big monitor that I could figure out what those blackbirds were doing. They were hopping up to eat flies!

Here's a series of shots showing one of the male red-wingeds in mid-hop.

  • Looking up, just before the hop:
Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong
  • Up he goes! See the very edge of the red epaulette on his right wing? And all those flies?
Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong
  • Is he going to catch something?
Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong
  • Maybe?
Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong
  • After all that, I'm not at all sure if he actually got anything!
Male red-winged blackbird (Agelaius phoenicius) at Waddell Beach
2021-09-14
© Allison J. Gong

I don't have any hard evidence that the blackbirds (both Brewer's and red-wingeds) are catching flies. And while I was at the beach watching them hopping up and down I had no idea what they were doing. However, now that I've seen the flies in the photos, it makes sense that the birds would be hopping up to catch and eat them, especially since both sexes of the Brewer's blackbirds were doing the same thing.

So that's what was hoppening at the beach!

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Published on 1 Comment on Anniversary

One year ago today a lightning storm settled over the Santa Cruz Mountains and dry lightning ignited a bunch of wildfires. Given the drier-than-normal conditions at the time the fires took off like crazy and eventually merged into one megablaze that CalFire dubbed the CZU Lightning Complex fire. The CZU Lightning Complex fire burned over 80,000 acres in Santa Cruz and San Mateo Counties before being contained by CalFire on 22 September. It raged through Big Basin Redwood State Park and destroyed the buildings at the park headquarters up in the mountains. Several mountain communities were threatened, with over 1400 structures destroyed. I personally know two families whose homes were lost, and many others who evacuated. We were also ready to evacuate, with bags packed and a place to flee to.

To commemorate the first anniversary of the CZU Lightning Complex fire the Santa Cruz Museum of Natural History and the Santa Cruz Public Library put together a series of events called "CZU and You" to teach the public about this particular natural disaster. This past weekend we attended a walk through Rancho del Oso, led by Richard Fletcher, who is one of the California State Parks interpretive rangers. Rancho del Oso sits in a little valley that I think of as the "bottom" of Big Basin Redwood State Park. It ends at Highway 1 directly opposite Waddell Beach. In previous years I have taken my Ecology class to Rancho del Oso for the first field trip of the semester. Rancho del Oso was cleared to reopen for visitors on weekends only just a few weeks ago.

My nature journal entry
2021-08-14
© Allison J. Gong

The Nature and History Center at Rancho del Oso is housed in the building that was the residence of Hulda Hoover McLean, who was the niece of President Herbert Hoover. Hulda and her husband, Charles, raised a family in the Rancho; Hulda taught her children about the natural history of the area. She sold her 40 acres of land and her home to the Sempervirens Fund in 1985, with the intent to create a place where people could visit and learn about this part of the natural world. There was one ranger on site on August 16, 2020 when dry lightning ignited the fire on the hillside directly across Waddell Creek from the nature center. He managed to flag down a single fire truck and crew. Working through the night this handful of people built a backfire to burn up the hill towards the flames that had sped around the house and were approaching from the other side, and sweeping off the burning embers that landed on the roof

The first things that Ranger Fletcher showed us were some cones from Monterey pine (Pinus radiata) trees. He described this species is being moderately serotinous, meaning that seeds don't fall out of the cones until they are exposed to the heat of a fire. Heat dries and opens up the cones, allowing the seeds to fall and be dispersed.

  • Unopened cones of Pinus radiata
  • Scorched and opened cones of Pinus radiata

In the area this backfire burned, literally across the driveway from the nature center, we could see some of the fire followers. These are the first plants to show up after a fire. Some of them may have arrived by seed, but many are regrowth from underground roots or bulbs.

The naked lady lilies (Amaryllis belladonna) are non-native ornamental bulbs that have been planted in gardens all over the region. They are called naked ladies because their leaves die back completely before the stalk blooms in late summer; you can see all the brown leaves at the bases of the flower spikes. In this first bloom season after the fire they seem more vibrantly pink than usual. The other foliage in the foreground is a blackberry (Rubus sp.) that could be either native or not. In the background you can see some bracken fern (Pteridium sp.).

Naked ladies (Amaryllis belladonna) in burned area at Rancho del Oso
2021-08-14
© Allison J. Gong

After a disturbance such as a fire the process of ecological succession is reset. Given the European colonizers' habit of suppressing all fire, it had been at least 100 years since the Waddell Valley burnt. In the many decades since the previous fire the homesteaders and ranchers had planted all sorts of non-native ornamental plants in their gardens. The naked ladies and invasive blackberries are examples of plants that are well suited for our Mediterranean climate, and they certainly made a showy return after the CZU Lightning Complex fire.

Fortunately it's not just the non-natives that are coming back. The ranger was excited to point out that one yellow bush lupine (Lupinus arboreus) had popped up on this same slope. Lupines are good plants to have on burnt slopes because they help stabilize the soil. They are also nitrogen fixers, which makes the soil more hospitable to other, hopefully native, plants.

Bush lupine (Lupinus arboreus), bracken fern (Pteridium sp.) and naked ladies (Amaryllis belladonna) in burned area at Rancho del Oso
2021-08-14
© Allison J. Gong

One plant that I hadn't expected to see in this location is Equisetum, the horsetail. There is a lot of Equisetum along the Marsh Trail, and I associated this plant with wetlands. So why was it growing on this particular slope, which is measurably drier than the Marsh Trail? It was growing really well, too!

Equisetum in burned area at Rancho del Oso
2021-08-14
© Allison J. Gong

And see how lush it is growing along the Marsh Trail?

Equisetum along Marsh Trail at Rancho del Oso
2021-08-14
© Allison J. Gong

We hiked the Marsh Trail—how could there be so many mosquitos when we're in such a bad drought??—and crossed Waddell Creek to where the Skyline to the Sea trail ends (or begins, if you were to start at the beach and hike uphill). This is where Ranger Fletcher told us more about the fire itself and its ongoing effects.

We were hiking at Rancho del Oso on a foggy morning. It was so very different last year, when the marine layer abandoned us early in the summer and left us to dry out just in time for the dry lightning in mid-August. But this is the area where the first lightning strikes hit ground:

Hillside northwest of Waddell Creek, where the Waddell fire began
2021-08-14
© Allison J. Gong

Once the fire was extinguished this hill was covered with black, burnt vegetation. Anything green is vegetation that has grown since then.

CalFire declared the CZU Lightning Complex fire contained on 22 September 2020 and controlled on 23 December. What nobody knew at the time was that the fire remained burning underground. Considering their great height, redwood trees don't have deep roots. But they have lateral networks of roots that entwine with those of neighboring trees (which are likely to be clonemates) and form a more or less solid mesh that holds all of the trees up. The fire travelled along this root network and continues to burn. One of our group asked "What is there to burn, if the roots have already burnt?" and Ranger Fletcher explained that now there are tons of charcoal buried in the ground, and we all know how well charcoal burns, right? Not being able to detect where roots are burning underground means it's difficult to evaluate trails and know when they are safe. Just last week a ranger was working up at Big Basin and stepped into what turned out to be a cavern containing burning embers. CalFire estimates that the fire will continue to burn underground for another four years. Trees that were weakened or killed by the fire will also be falling. It will be several years before the Skyline to the Sea trail opens again. But in the lifespan of a redwood forest, five or even ten years would be a blink of the eye. And I'd just as soon not step into a burning hole while hiking, thank you very much.

On this side of Waddell Creek you can see the meadow that acts as a buffer zone between the mountains and the ocean. When wildfires burn through hilly areas, we worry about winter rains causing mudslides. This past winter we got hardly any rain at all, so at least the mudslides didn't materialize. But even when there aren't mudslides, a lot of nutrients wash downhill towards the ocean. The meadow is a biological sponge that soaks up these nutrients and keeps them from creating problems in the marine habitat. This is one of the reasons that wetlands are such important players in the health of coastal ecosystems. I took this photo from the Highway 1 bridge that crosses Waddell Creek. Just on the other side of the highway the creek spills onto Waddell Beach.

Waddell Creek and flanking wetlands
2021-08-14
© Allison J. Gong

From a fire behavior perspective the CZU Lightning Complex fire was unusual. Fires usually burn up hills, but this one burned downhill towards the ocean. Waddell Beach is almost always foggy, and the marine layer can be felt away from the beach, as it was on our most recent visit to Rancho del Oso. This marine influence should have acted to keep the fire from racing downhill as fast as it did. Alas, the marine layer was not doing its job last summer. If it had been, we wouldn't have seen so many lightning strikes in the first place. The paucity of rain from the previous winter didn't help things, either. Climate change is coming back to bite us in the ass. Around the world we are seeing extreme weather events, from severe drought to equally devastating floods to heat records tumbling by the wayside. We are living in the era of anthropogenic climate change, and we will not be alive when an equilibrium returns to Earth's climate. In the timeframe of a human lifespan, however, it is nice to see and document how this small part of the landscape is recovering from last year's fires. Now that Rancho del Oso is open again I'll try to get up there every so often to record changes in my nature journal.

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Published on 4 Comments on Ready for battle

For some reason, many of the sunburst anemones (Anthopleura sola) in a certain area at Davenport Landing were geared up for a fight. I don't know what was going on before I got there yesterday morning, but something got these flowers all riled up. We think of them as being placid animals, but that's only because they operate at different time scales than we are used to. A paradox about cnidarians is that they don't do anything quickly except fire off their stinging cells; that, however, they do with the fastest known cellular mechanism in the animal kingdom. Go figure.

Pale green sea anemone with slender feeding tentacles surrounding the oral disc. Below the ring of feeding tentacles there is a ring of thick club-shaped tentacles used for fighting.
Sunburst anemone (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

What looks like an anemone wearing a tutu is actually an anemone ready to fight. The normal filiform feeding tentacles are easily recognized. But those club-shaped white tentacles below the ring of feeding tentacles are called acrorhagi. They are all about fighting. The tips are loaded with potent cnidocytes that usually aren't used to catch food. They are used to fight off other anemones, and possibly predators.

Here's another shot of the same animal, which shows how the feeding tentacles and acrorhagi are arranged in concentric rings:

Pale green sea anemone with slender feeding tentacles surrounding the oral disc. Below the ring of feeding tentacles there is a ring of thick club-shaped tentacles used for fighting.
Sunburst anemone (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

So who would this anemone be fighting? This individual was the only one of its kind in the pool where it lives. I don't know why its acrorhagi are inflated. I suppose they could be used to fend off a would-be predator, but I didn't see any other animal in the pool that seemed a likely candidate.

But look at this duo:

Two pale green sea anemones with slender feeding tentacles surrounding the oral disc.The anemone on the right has inflated fighting tentacles. The animal on the left has fewer inflated fighting tentacles.
Sunburst anemones (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

Now, clearly there is (or had been) something going on between these individuals. They both have their acrorhagi inflated. I've been looking at this photo for a while and can't decide which is the aggressor. At first I assumed that the anemone on the right had initiated an attack on the other. But now I wonder if that is a defensive posture rather than an offensive one. That animal does seem to be more bent out of shape than the one on the left.

I've seen anemone fights before, and I've also seen anemones living side by side, tentacles touching, in apparently perfect amity. It's very clear that they can coexist peacefully. Why, then, do they sometimes choose to fight? It's important to point out that Anthopleura sola is an aclonal species. Unlike its congener A. elegantissima, whose primary mode of growth is cloning, each A. sola represents a unique genotype. With these anemones, whether or not two individuals fight is not determined by relatedness.

In a different pool these two anemones are sharing the carcass of a rock crab.

Sunburst anemones (Anthopleura sola)
2021-06-27
© Allison J. Gong

Maybe that third anemone at the top had also taken part in the feast, but at this point it seemed to be minding its own business. Given the demonstrated aggression of some A. sola, it would be interesting to know whether or not this trio ever fight amongst themselves. When we 'ooh' and 'aah' over them in the tidepools they look like passive flowers, and we forget that they are active predators. But we humans have access to the anemones' home for only a few hours every month, and I have no doubt that they get up to all sorts of shenanigans when we're not looking.

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Published on 3 Comments on Letting gravity do the work

This morning I went to Natural Bridges. The tide this morning was the lowest of the season, but early enough that for the most part I had the intertidal to myself for a couple of hours. I always like those mornings best.

I did meet a docent out there, and we chatted for a few minutes. Towards the end of the excursion, when the tide had turned and I realized I had to get to the marine lab for the usual Friday feeding chores, she pointed out something that didn't make sense to her. She described it as two anemones side-by-side, but one was really stretched out down towards the water. She wondered what could be going on, as the other anemone looked normal.

Two large sea anemones at the edge of a tidepool. The anemone on the left is stretched down to more than twice the length of the anemone on the right.
Sunburst anemone (Anthopleura sola) and giant green anemones (Anthopleura xanthogrammica)
2021-06-25
© Allison J. Gong

Looks strange, doesn't it? What this anemone is doing, I think, is disgorging the remains of its most recent meal. If you look at the oral end, which is indeed stretched down towards the sandy bottom of the pool, you can see two things sticking out. The whitish blob is the internal part of the anemone's pharynx. It is not at all uncommon for anemones to sort of prolapse the pharynx, especially after a big meal. Remember, anemones have a two way gut with a single opening for both food ingestion and waste expulsion. The other thing sticking out of the mouth is a clump of mussel shells thickly coated with slime.

Here's a close-up of what's going on at the mouth of this anemone:

Sunburst anemone (Anthopleura sola) disgorging mussels
2021-06-25
© Allison J. Gong

It's hard to tell whether or not the mussels have been opened and digested by the anemone. It looks like at least some of the acorn barnacles attached to the mussel might still be alive, although smothered in slime. Nor can we see how many mussels are still inside the anemone's gut. In any case, the anemone is getting rid of this part of the mussel clump. However, this isn't a phenomenon that can really be watched, unless you can watch in time-lapse. The docent asked, "Doesn't it use peristalsis, or something like that?" The answer is that no, anemones don't use peristalsis. They don't have the type of muscles that can contract in that way. The anemone still has to somehow expel wastes and undigestible matter from its gut, through that single opening that we call a mouth but functions as both mouth and anus.

Our human gut, of course, uses peristalsis to move food along from esophagus to rectum. And while for the most part we don't like to think about how that works, we have all experienced what happens when things don't go as planned. I doubt that anybody gets through life without vomiting, so it is probably safe to say we all know that it is a violent way to thoroughly expel food, toxins, and other noxious items from the stomach. Anemones, however, have no peristalsis and cannot vomit. How, then, does an anemone void its gut of something larger than the typical digestive waste?

This particular anemone is ideally situated to let gravity do the work. Hanging down like this and relaxing the simple sphincter muscle around the base of the tentacles will allow the mussel clump to eventually fall out. Without peristalsis to speed things along, it will probably take a while. Would it be finished by the time the tide comes back? I couldn't stick around to watch, so I can't say. But it was a very cool thing to see, even though it happens about as fast as paint drying.

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Published on 1 Comment on A busy place

In Morro Bay, CA, there is a stand of eucalyptus trees that has been designated a natural preserve. In 1973 the Heron Rookery Natural Preserve was established to protect great blue herons (Ardea herodias) as they nested. Since then other bird species have taken to nesting in these same trees. When we were there at the end of May we saw these species with nests in the eucalyptus trees:

  • Great blue heron (Ardea herodias)
  • Double-crested cormorant (Phalacrocorax auritus)
  • Great egret (Ardea alba)
  • Snowy egret (Egretta thula)

This particular rookery is not at all removed from human activity. It is right across the street from the municipal golf course and next to a hotel, and there is a walking/biking trail that runs directly under the trees. Signs advise people to keep their voices down, but pedestrians are walking under the trees all day, dodging the rainfall of guano from above. The birds don't seem to be bothered.

Unlike the Brandt's cormorants (Phalacrocorax penicillatus), which nest on cliffs and rocks, the double-crested cormorants nest in trees. Birds build nests with local materials, and there is a difference in what I could see making up the nests of these two species. The Brandt's cormorants at Natural Bridges in Santa Cruz were using seaweeds as the main building material; I could see birds flying back with algae in their beaks, and then either handing it off to a mate on the nest or tucking it into the existing structure itself. In some cases I could see the pieces of algae well enough to make a tentative ID.

Group of ~40 large black marine birds on a rock. ~12 nests of mounded algae, with a single bird lying on it. Other birds standing on rock, preening or presenting algae to their mate. Some birds show blue throats of breeding plumage.
Brandt's cormorants (Phalacrocorax penicillatus) nesting on rock arch at Natural Bridges
2021-05-14
© Allison J. Gong

Those are the Brandt's cormorants. The double-crested cormorants nest in the trees, as we saw at the heron rookery. Here's a pair that have a brood of three chicks:

Family of large black seabirds in a eucalyptus tree. The nest contains three chicks and one parent. The other parent is perched on a nearby branch.
Double-crested cormorant (Phalacrocorax auritus) parents and trio of chicks
2021-05-23
© Allison J. Gong

At Morro Bay, which is an estuary rather than a rocky area, the double-crested cormorants use a lot of eelgrass (Zostera marina) in their nests. Eelgrass is very abundant in the Morro Bay harbor and Estero, whereas the birds would have to fly a bit farther to gather algae. Eelgrass, being a true plant, is less slimy than the algae are, and these cormorants' nests look much drier than the mounds of algae used by the Brandt's cormorants up in Santa Cruz.

A short distance up the coast at San Simeon the double-crested cormorants were nesting in a smaller rookery, also in eucalyptus trees. I liked the pattern of how these four nests were situated in three-dimensional space:

Four nests in a dead eucalyptus tree. There is one adult black cormorant in each nest.
Double-crested cormorants (Phalacrocorax auritus) nesting at San Simeon
2021-05-23
@ Allison J. Gong

Returning to goings-on at the heron rookery in Morro Bay, the herons and egrets were also raising youngsters in that stand of eucalyptus trees. Remember, this rookery is very easily visited by humans. Here's a view of the trees, taken from the small parking area:

Grove of eucalyptus trees
Heron Rookery Natural Preserve in Morro Bay, California
2021-05-23
© Allison J. Gong

It's difficult to photograph the nests because of all the branches obscuring the view. We were also there near mid-day, with the overhead sun making lighting conditions less than favorable for good photography. I did find one comparatively visible heron nest, containing one parent and one sullen punk-ass teenager of a chick. The nestling had started growing feathers but was still almost half fluff, clearly not ready to fly yet.

Large gray-ish blue bird and its partially-feathered chick in their nest in a eucalyptus tree.
Great blue heron (Ardea herodias) nest at the Heron Rookery Natural Preserve
2021-05-23
© Allison J. Gong

Both great egrets (Ardea alba) and snowy egrets (Egretta thula) nest at the heron rookery. Here's a great egret nest with two chicks:

Large white bird with two white chicks in a nest in a eucalyptus tree
Great egret (Ardea alba) nest at the Heron Rookery Natural Preserve
2021-05-23
© Allison J. Gong

From what I could see, the herons and egrets don't use any marine material at all to build their nests. One factor that determines the suitability of a potential building material is proximity—even if a certain material is fantastic in other ways, birds may not use it (or may use less of it, compared to other materials) if it costs too much energy to fetch and bring back to the nesting site. For the herons at this site, sticks are easy to come by. Another thing to consider is that herons and egrets are not marine birds. Although some populations live and nest in coastal areas, most do not. Thus it is not surprising that their nests are built from materials that are terrestrial rather than marine.

I did not see any snowy egret nests in areas where they could be photographed well. However, there were some adult snowies in their spectacular breeding plumage. There was enough of a breeze to ruffle up those long plumes that used to be harvested to decorate ladies' hats.

Look at these beautiful birds!

White bird with long black legs and a black beak perched in a eucalyptus tree. Long white plumes blow away from the birds head, neck, and back.
Adult snowy egret (Egretta thula) in breeding plumage
2021-05-23
© Allison J. Gong
White bird with long black legs and a black beak perched in a eucalyptus tree. Long white plumes blow away from the birds head, neck, and back.
Adult snowy egret (Egretta thula) in breeding plumage
2021-05-23
© Allison J. Gong

For several decades now, the cormorants, herons, and egrets have been nesting in these eucalyptus trees, which brings to mind the consideration of native versus non-native species. The trees themselves, blue gum eucalyptus (Eucalyptus globulus) are non-native, having been imported to California from Australia starting in the 1870s. This introduction was encouraged by calls to replace native trees that had been cleared for fuel and building material, both of which were desperately needed during and after the Gold Rush. Since ecologists began considering the effects of non-native species in the 1980s there has been a backlash against the blue gums. Given their large size, their having been planted in groups to serve as windbreaks, and their propensity for dropping a lot of debris, they are very conspicuous, and it is easy to get all hot and bothered at how in certain places they dominate the landscape.

Great egret (Ardea alba) in flight
2021-05-23
© Allison J. Gong

At which point, however, does a species cease to be considered non-native? Having been established in California for 150 years, what is the role of E. globulus in the ecology of the Golden State? There are many people and organizations that would like to see the blue gums eradicated, or at least their populations greatly reduced. On the other side of the argument, groups such the San Francisco Forest Alliance posit that blue gums should be treasured as heritage trees.

At the Heron Rookery, some of the eucalyptus trees are dying. One reason is sheer old age. Another is the several decades' accumulation of bird wastes onto the soil, which is slowly killing the trees. As the blue gums die, the birds will have to find other places to nest. One of the pro-eucalyptus arguments is that many species of native birds—not just these here but other species such as red-tailed hawks, red-shouldered hawks, and a whole host of songbirds—nest in eucalyptus trees throughout the state. If the blue gums are removed, then where will these undoubtedly native birds nest? Especially if the native trees have long been gone?

Taking the long view, my guess is that the birds will figure it out. Ecological communities evolve over thousands of years. The 150 years of the eucalyptus trees' presence in California seems like a long time, but in terms of ecological time they are merely a blink of the eye. The herons, egrets, and cormorants have been nesting at the Heron Rookery for an even shorter period of time. When this stand of blue gums is gone, due to either natural attrition or removal by humans, the birds will find another place to nest. They might not choose a place that is so easily visited and observed by people, though.

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Published on 2 Comments on Serendipity, once again

Sometimes things just work out, through no fault of my own. In terms of good minus tides occurring in daylight hours, this weekend's tides are the best we will have all season. Today (Saturday 29 May) is the third of five intertidal excursions I have planned. This morning I went up to Pistachio Beach to collect some things for the Seymour Center. I always feel a teensy bit apprehensive agreeing to collect for anybody but myself, because it is quite likely that I will get skunked and not be able to bring back what is needed. So usually I just agree to keep my eyes open for things that are on the wish list and make no promises.

The current wish list for the Seymour Center includes fishes. I've already brought them some sculpins and a clingfish, but small pricklebacks are also welcome. Pistachio is a popular place for people who fish for large pricklebacks. Apparently they (the pricklebacks) put up a good fight and make tasty eating. The usual way of fishing for them is poke-poling. I am not entirely sure how that works, but it involves a long pole and baited hooks. I think the idea is to lure a prickleback out from its hiding place at low tide, when it is sort of stranded away from open water. Adults get up to 70-80 cm long, and are as big around as my forearm.

Unlike the fishermen, I was fishing for young pricklebacks, hoping to find some that were about the length of my hand. Possessing the ideal set of characteristics for avoiding capture—a long eel-like body, small head, slimy coating, and the ability to augur really quickly into even the tiniest crack amongst the cobbles—these small fish led me on a merry chase for quite a while. However, the advantages that I have over even a wily prickleback are an enlarged cerebral cortex, opposable thumbs, and the dexterity to use both a dip net and a zip-loc baggie. When all was said and done I had two appropriately sized pricklebacks in my baggie, and two others had gotten away from me. Oh, and I did also bag another clingfish!

Having had that bit of success and not wanting to press my luck, I started poking around just for the hell of it, without any clear objective in mind. As I've said before, what we gain from a super low tide like this (-1.6 ft) is not only access to more real estate in the low intertidal, but more time to spend there before the tide returns. I took lots of photos, which I will present in chronological order. These will give you an idea of what it was like out there this morning.

Even the hike across the beach yielded something nice—this small stand of Postelsia palmaeformis, the sea palm. These poor junior kelps will be taking a beating with these spring tides rushing up and down. That's the price they pay for living out there on those exposed rocky points.

Group of 6 sea palms on the beach
06:53 Postelsia palmaeformis
2021-05-29
© Allison J. Gong

The leather star Dermasterias imbricata isn't one of the most common stars in the intertidal around here. It was one of the species that was hit pretty hard by the most recent outbreak of Sea Star Wasting Syndrome. We see one every so often, but they are nowhere as abundant as the ochre stars or bat stars.

07:10 Dermasterias imbricata
2021-05-29
© Allison J. Gong

Pistachio Beach isn't the best place for large anemones, but of course there are some. This is one of the few big Anthopleura anemones that I saw today. There are many of the small cloning anemones, A. elegantissima, in the high intertidal, as well as the moonglow anemones, A. artemisia, in the mid and low sandy areas.

07:12 Anthopleura xanthogrammica
2021-05-29
© Allison J. Gong

I was so pleased to see my favorite red alga doing really well in the low zone! It is so pretty.

Red seaweed
07:29 Erythrophyllum delesserioides
2021-05-29
© Allison J. Gong

And at the same time I accidentally discovered a pretty big rock crab, which was tucked under a rock. For its species, this one was pretty calm and didn't come at me with big claws up. It could be that this crab is a male, and is clasping a female beneath him. I didn't check.

Dorsal view of a rock crab
07:29 Romaleon antennarium
2021-05-29
© Allison J. Gong

One of the things I found while turning over rocks to look for fish is this purple urchin:

Sea urchin with purple and green coloration
08:02 Strongylocentrotus purpuratus
2021-05-29
© Allison J. Gong

And a bit later, a nice healthy group of Dictyoneurum californicum. As these thalli age, they will develop longitudinal splits at the base of the blades. Right now they are young and crispy.

Blades of a brown seaweed with a waffle-like texture
08:15 Dictyoneurum californicum
2021-05-29
© Allison J. Gong

And who can resist such an exuberantly decorated limpet? Certainly not I! Reminds me of the fancy hats that ladies used to wear for Easter. Or Beach Blanket Babylon.

Limpet heavily fouled with encrusting and upright coralline algae
08:28 Limpet, probably Lottia sp.
2021-05-29
© Allison J. Gong

Chitons, the overlooked molluscs that reach peak abundance and diversity in the intertidal, can be very common along the coast. Species composition varies from site to site, though. Here at Pistachio Beach, the two species of Tonicella are very common. I found several of them on the undersides of rocks. This one is T. lokii.

Chiton with dark wavy lines on the shell plates and alternating pink and beige patches on the girdle
08:52 Tonicella lokii
2021-05-29
© Allison J. Gong

After two hours of catching fish and looking around, I was getting cold. Time to head back up and out. That took an additional half-hour or so, because I kept getting distracted by the algae. For example, look at how beautiful this Fucus is. And note the swollen tips, which mean this thallus is getting sexy. 'Tis the season, after all.

Olive-green seaweed with wide dichotomous branches and swollen branch tips
09:15 Fucus distichus
2021-05-29
© Allison J. Gong

One of the other rockweeds, Pelvetiopsis limitata, was also very thick and abundant.

Olive-green seaweed with narrow dichotomous branches
09:19 Pelvetiopsis limitata
2021-05-29
© Allison J. Gong

The rockweeds share the high intertidal with a few species of red algae. The most common reds in this zone are the two (or however many there are) species of Mastocarpus, and Endocladia muricata.

Reddish-brown seaweed with wavy blades, covered with tiny bumps
09:21 Mastocarpus papillatus
2021-05-29
© Allison J. Gong

I always want to stop and look around in the high zone on my way down. Because when I walk past sights like this, it's hard not to stay and study more closely. Then I remember that I can take as much time as I want in the high zone on the way out. This morning I took lots of photos of these reds and rockweeds.

How many different types of seaweed can you see?

09:24 High intertidal algal assemblage
2021-05-29
© Allison J. Gong

So there you have it, my morning summarized in about a dozen photos. I hope your Saturday was as enjoyable as mine was!

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