Skip to content

It's the time of the year for students to graduate from one stage of their education to the next. We don't have students of our own at home, unless you count the cats, but we graduated some 10,000 or so bees! Let me explain.

Since the car accident and head injury in 2016, my activities as a beekeeper had been limited to advising from far away and helping with the honey wrangling. I didn't trust myself to: (1) not freak out; (2) be able to think calmly and carefully while surrounded by thousands of stinging insects; (3) be able to read a hive and intuit what needed to be done; and (4) not do something stupid, like drop a frame of bees, and piss them all off. It has taken me four years to feel confident enough to dig through a hive again. Yesterday I helped, and it wasn't like cat help--my help actually made things go faster.

At one point we had bees in three separate apiaries. Over the years we've been consolidating, and now all of our hives are in one spot. This makes it a lot easier to keep track of everything and to know where all of the equipment is. Even so, over the past year or so we had let our attention lapse and become rather dismal beekeepers. At the end of calendar year 2019 we had lost all of our hives.

We became beekeepers again when a swarm moved themselves into the Purple hive, which was still set up because we were too lazy to dismantle it. So hey, free bees! That was pretty cool. And the same day, Alex got a swarm call, so we went from zero hives to two hives in the course of an afternoon. That swarm went into the Green hive. Within the next few weeks we got two more swarms, one of which went into the Rose hive and a tiny one that went into the nuc. A nuc is a small 5-frame box for little colonies; some beekeepers sell nucs as starter colonies. Our nuc happens to be painted the same color as the Rose hive.

Four, count 'em, four hives!

Fast forward a month of strong nectar flow, and the established colonies (Purple, Pink, and Green) are all putting up lots of honey. Even the swarm in the little nuc was growing; they probably had a virgin queen that needed to get mated, so it would take about three weeks for the number of bees to begin increasing. Yesterday we went through the hives to check on things and provide space. We also took nine frames of honey, fully capped, out of Green. In the next couple of weeks there might be two more full boxes of honey that we can take. All told, there will be close to 100 pounds of honey for us to extract soon. And the early season honey that the bees make at this location is really good--light and buttery, slightly floral but not pungent. We call it popcorn honey because when it's warm the hives smell like buttered popcorn.

Four bigger hives!

You'll notice that Green now has two brown boxes? Those are honey supers, boxes where we want the bees to put honey stores. Rose also has two more boxes, one blue and one brown. The blue box is also intended as a honey super. The little nuc, which has grown to about 10,000 bees now, has graduated into the Yellow hive. They now have lots of space to expand into. We left the empty pink nuc on top of Yellow, so any returning foragers can recognize that the home they left is still there and find their way into their new residence.

And yes, we name our hives by color. I don't remember that it was something we planned, it just sort of happened. In addition to the four established hives, we also have equipment for Blue, Aqua, and Orange hives. In a perfect world we'd be able to keep each hive in one color of boxes in addition to the brown honey supers, but as time goes by we end up swapping boxes as needed and things get jumbled. The bees don't care, after all.

Today was the first time I've gone out on a low tide since before the whole COVID19 shelter-in-place mandates began. Looking back at my records, which I hadn't done until today because it was much too depressing, I saw that my last time out was 22 February, when the low tides were in the afternoon. At the time I made what seemed to be the not-too-bad decision to stay away from the remaining afternoon lows and wait until the spring shift to morning lows, which I like much more. And then then COVID hit and we all had to stay home and beaches were closed. So yeah, it has been much too long and I really needed this morning's short visit to the intertidal.

Pair of black oystercatchers (Haematopous bachmani) at Mitchell's Cove
My companions for a short while this morning, a pair of black oystercatchers (Haematopus bachmani) at Mitchell's Cove
© Allison J. Gong

Beaches in Santa Cruz County are closed between the hours of 11:00 and 17:00, except that we are allowed to cross the beach to get to the water. This means that surfers, kayakers, SUP-ers, and marine biologists can get out and do their thing. Of course, my particular thing took place hours before the beach restrictions began, so I was in the clear anyway. I didn't venture too far from home, as I wasn't quite certain how easy it would be to get down to the beach.

Spring is the prime recruitment season for life in the intertidal. The algae are coming back from their winter dormancy, and areas that had been scraped clean by sand scour or winter storms are being recolonized. Many of the invertebrates have or will soon be spawning. And larvae that have spent weeks or even months in the plankton are returning to the shore to metamorphose and begin life as an adult. Just as it is on land, spring is the time for life in the sea to go forth and multiply.

For several decades now, marine ecologists have been studying barnacles and barnacle recruitment. Barnacles are a nice system for studying, for example, recruitment patterns and mortality. The cyprid larva, the larval stage whose job it is to find a permanent home in the intertidal, readily settles and metamorphoses on a variety of man-made surfaces; this makes it easy to put out plates or tiles and monitor who lands there. The fact that barnacles, once metamorphosed, remain attached to the same place for their entire lives means an ecologist can measure mortality (or survivorship, which is the inverse) by counting the barnacles every so often.

These are young barnacles (Chthamalus sp.), about 4-5 mm in diameter. I don't know how old they are, but would guess that they recruited in the past couple of months. These individuals all found a nice place to set up, because as I've written before, barnacles need to be in close proximity to conspecifics in order to mate.

Young acorn barnacles (Chthamalus dalli/fissus) on a rock at Mitchell's Cove
Small barnacles (Chthamalus sp.) on a rock at Mitchell's Cove
© Allison J. Gong

This is a mixed group of Chthamalus sp. and Balanus glandula. Balanus is taller and has straighter sides and a more volcano-like appearance. Larvae of both genera recruit to the same places on rocks in the intertidal, and it is not uncommon to see assemblages like this.

Mixed assemblage of Balanus and Chthamalus barnacles at Mitchell's Cove
Barnacles Balanus glandula and Chthamalus sp. at Mitchell's Cove
© Allison J. Gong

Both species of barnacles are preyed upon by birds, sea stars, and snails. Predatory snails use their radula to drill a hole through the barnacle's plates and then suck out the body. Some of the barnacles in the photo below are dead--see the empty holes? Those are barnacles that were eaten by snails such as these.

Small barnacles and predatory snails at Mitchell's Cove
© Allison J. Gong

What was unusual about this morning was the number of snails of the genus Acanthinucella. I don't know that I've ever seen this many of them before.

Large group of Acanthinucella snails at Mitchell's Cove
© Allison J. Gong

Lots of Acanthinucella means that lots of barnacles are being eaten. And empty (i.e., dead) barnacle tests are more easily dislodged from the rock than live ones are. A lot of dead barnacles could result in bare patches. And guess what? That's what I saw this morning!

Bare patches in barnacle population
Bare patches in barnacle population at Mitchell's Cove
© Allison J. Gong

And those aren't just empty spaces where nobody settled. Notice the clean edges. These empty spaces formed because barnacles were there, but died recently and fell off. The abundance of Acanthinucella may have indirectly caused these patches to form--by eating barnacles and weakening the physical structure of the population. Bare space is real estate that can be colonized by new residents. See?

Newly settled barnacles
© Allison J. Gong

These brand new recruits are about 1 mm in diameter. No doubt more will arrive in the coming months, and this patch will fill up with barnacles again. Vacant space is a limited resource in the rocky intertidal, and the demise of one generation provides opportunity for new recruits. And if the barnacles themselves don't occupy all of the space, then other animals and algae will. That's one of the things I love about the intertidal--it is a very dynamic habitat, and every visit brings something new to light. No wonder I missed it so much!


I'm willing to bet that when you think about coral, what comes to mind is something like this:

Great Barrier Reef
A Blue Starfish (Linckia laevigata) resting on hard Acropora coral. Lighthouse, Ribbon Reefs, Great Barrier Reef
© 2004 Richard Ling

The reef-building corals of the tropics are indeed spectacular structures, incredibly rich in biodiversity and worthy of a visit if you ever get the chance. These coral colonies come in many shapes, as you can see in the photo above. Each colony consists of hundreds or thousands of tiny polyps, all connected by a shared gastrovascular cavity, or gut. The living polyps secrete a skeleton of CaCO3, which grows slowly over decades or even millennia as successive generations of polyps live their lives and then die. It's this slow accumulation of CaCO3 that makes up the physical structure of the reef.

Reef-building corals are members of the Scleractinia, the so-called stony corals. The stoniness refers to the calcareous skeleton that they all have. But not all corals live in the tropics. We actually have two species of stony corals in Northern California. The brown cup coral, Paracyathus stearnsi, lives subtidally, and I think I've seen maybe a handful in all my intertidal explorations. The orange cup coral, Balanophyllia elegans, extends up into the low intertidal, and can be very common at certain sites I visit regularly. When I see them at low tide they are emersed and look like orange blobs. But if you touch one with your finger, you can feel the hardness of the calcareous base.

Orange cup corals growing among coralline algae
Orange cup coral (Balanophyllia elegans) at Asilomar
© Allison J. Gong

Stony corals they may be, but Paracyathus and Balanophyllia are both solitary; that is, they aren't colonial. Each polyp developed from its own larva and lives its own life independent from all other corals. Its bright orange color makes Balanophyllia pretty conspicuous, even though most of them are less than 10 mm in diameter. They do occur in patches, which makes one wonder. If they're solitary rather than clonal or colonial, how do these patches arise?

To answer this question we need to venture into the lab and examine the biology of Balanophyllia more closely. Fortunately, they grow in the lab quite happily. Years ago my friend Cris collected a bunch of Balanophyllia and glued them to small tiles so they could be moved around and managed in the lab. Cris has since moved on to other things, but the corals remain in the lab to be studied. They are beautiful animals, and can't really be appreciated in the intertidal because at low tide they're all closed up. But look at how pretty they are when they're relaxed and open:

Group of adult cup corals, Balanophyllia elegans
Cluster of orange cup corals (Balanophyllia elegans)
© Allison J. Gong

Like all cnidarian polyps, these corals have long tentacles loaded with stinging cells, or cnidocytes. See the little bumps on the otherwise translucent tentacles? Those are nematocyst batteries, clusters of stinging cells.

Orange cup coral, Balanophyllia elegans
Orange cup coral (Balanophyllia elegans)
© Allison J. Gong

Let's get back to the biology of this beast and how it is that they seem to live in groups. Balanophyllia is a solitary coral with separate sexes--each polyp is either male or female. They are also brooders. Males release sperm, which are ingested by a nearby female. The female broods fertilized eggs in her gastrovascular cavity. After a long period, perhaps several months, a large reddish planula larva oozes out of the mother's mouth and crawls around for a while, generally settling and metamorphosing near its parent.

Planula larva of Balanophyllia elegans
Planula larva of Balanophyllia elegans
29 April 2020
© Allison J. Gong

This planula is a very squishy elongate blob, and can measure anywhere from 1-4 mm in length. It is an opaque red color, has a ciliated epidermis, and lacks a mouth or digestive system. Instead of feeding, it survives on energy reserves that its mother partitioned in the egg. You might surmise that not being able to eat would necessitate a quick metamorphosis into a form that has a mouth, but you'd be wrong. While some of them do indeed settle and metamorphose very close to their parent, others crawl around for several weeks, showing no inclination to put down roots and take on life as a sessile polyp. Perhaps they can take up enough dissolved organic matter from the seawater to sustain them through a long period of fasting.

At some point, though, the larva settles and metamorphoses into a little polyp. In the lab at least, Balanophyllia larvae settle on a variety of surfaces--glass, various plastics, even the fiberglass of the seawater tables.

Juvenile cup coral and three planula larvae of Balanophyllia elegans
Recently metamorphosed coral and three planula larvae of Balanophyllia elegans
© Allison J. Gong

The little coral measures about 2 mm in diameter and has 12 tentacles. It feeds very happily on brine shrimp nauplii and should grow quickly. Those three larvae, though, may hang around forever. I got tired of waiting for them to do something and released them into the seawater system. It might or might not have been an accident.

So there we have it. Our local cold-water coral, which doesn't form reefs or live in colonies. Balanophyllia may seem atypical for corals, but what it really demonstrates is the diversity within the Scleractinia. It reminds us that generalities do indeed have some value, and that for the discerning mind it is the exceptions to the generalities that are most interesting.

%d bloggers like this: