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. . . taking a small group of highly motivated students into the field!

My invertebrate zoology class this semester has only 10 students, which allows me a lot more freedom to improvise on the fly and actually participate in the course instead of having to stand back and supervise 30 of them at the same time.

Most of my class getting started on their investigative journalist assignment at Point Pinos. 27 October 2015 © Allison J. Gong
Most of my class getting started on their investigative journalist assignment at Point Pinos.
27 October 2015
© Allison J. Gong

Their job was to interview at least six marine invertebrates and suss out answers to the Big 6 questions: Who? What? When? Where? Why? and How? In other words, to do a small bit of preliminary ecological investigation into animals they don't already know much about. Some of the students also used the time to scope out the site for their independent research projects, which they will be starting soon.


. . . serendipity!

This past couple of classes I lectured on Platyhelminthes and Nemertea, and we saw both on the field trip.

The flatworm, Eurylepta californica, was spotted by a keen-eyed student, who thought at first it was a nudibranch but then noticed the ruffling edge and decided it must be something else.

Eurylepta californica, the "chocolate drizzle" polyclad flatworm, at Point Pinos. 27 October 2015 © Allison J. Gong
Eurylepta californica, the "chocolate drizzle" polyclad flatworm, at Point Pinos.
27 October 2015
© Allison J. Gong

This individual was a bit less than 2 cm long. I've only seen it at Point Pinos. Such a cool animal!

Some day I want to find one of these at a site where I can collect, and bring it back to the lab for closer observation.

On each of these class field trips to the intertidal there's at least one conversation that goes something like this:

  • Student: Allison! I found this thing! What do you think it is?
  • Me, from several rocks over: Well, what does it look like?
  • Student gives a vague description, which usually isn't very helpful.
  • Me: Is it alive?
  • Student: I think so.
  • Me: Color?
  • Student: Sort of orange. (or brown or purple or whatever)
  • Me: Shape? Size?
  • Student: This big (holds up fingers or hands to indicate size, then describes shape).
  • Me: Is it hard or squishy?
  • Student: I don't want to touch it! Is it going to hurt me?
  • Me: Not unless it's a big crab. Just touch it and tell me what it feels like!
  • <pause>
  • Student: Hey, it didn't hurt me!

This conversation occurs as I make my way over to see what it is. Eventually I can take a look at the whatever-it-is and explain as best I can. The nemertean that we saw yesterday resulted in a conversation similar to this, but the student had pretty much decided on her own that she had found a nemertean. By the time I made it over to where she was pointing the worm had just about disappeared into a mussel bed, which is where they hang out. I could see enough to determine that it was Paranemertes peregrina.

Paranemertes peregrina, a nemertean worm, at Pistachio Beach. 31 January 2015 © Allisoin J. Gong
Paranemertes peregrina, a nemertean worm, at Pistachio Beach.
31 January 2015
© Allisoin J. Gong

Nemerteans are unsegmented, slimy, predatory worms that feed by shooting out a sticky proboscis and wrapping it around prey. Some have a stylet at the end of the proboscis with which they can repeatedly stab the prey and inject toxins. They may not be much to look at, but watching them in action should make you glad that you're not a small animal.


. . . being in the right place at the right time!

Yesterday we saw octopuses! Three of them, I think. And one of the most glorious sea anemones I have ever seen.

Octopus rubescens crawling around at Point Pinos. 27 October 2015 © Allison J. Gong
Octopus rubescens crawling around at Point Pinos.
27 October 2015
© Allison J. Gong
A beautiful Anthopleura xanthogrammica anemone at Point Pinos. 27 October 2015 © Allison J. Gong
A beautiful Anthopleura xanthogrammica anemone at Point Pinos.
27 October 2015
© Allison J. Gong

The octopuses that were out of the water were duly rescued by my students. The red one that I photographed turned out to about the length of my hand when it swam away into the depths of a tidepool. Watching the students release this little animal back into the water was a fitting way to close out what had been a fantastic field trip.

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If I were the type of person to make and keep a bucket list, today I would have been able to cross off one item. For some reason until today I'd never managed to get to Ed Ricketts' Great Tidepool, even though I'd been several times to Point Pinos which is right around the corner. Today I had intended to do some collecting for a colleague back east, but it was just as well that those plans changed as I didn't find what I was supposed to collect. However, since I had blocked out the time I thought I might as well take advantage of the opportunity to scope out a new site.

Now that we're back in afternoon low tides, fighting darkness becomes a real problem. Today's low tide was at 16:28 and I had plenty of time to poke around and explore. Tomorrow I'm taking my class to the intertidal for an afternoon field trip, and on Wednesday I'll do some collecting of my own, almost literally racing against nightfall. Still, it was wonderful just to be out there again.

Sign

I'd heard about all the sea hares in the intertidal, and they were out in full force this afternoon. There were dozens of them, hanging out in ones and twos, either emersed or submerged just below the water line. They are big animals, about the size of a football, and silky soft to the touch.

California sea hare (Aplysia californica) in the Great Tidepool in Pacific Grove. 26 October 2015 © Allison J. Gong
California sea hare (Aplysia californica) in the Great Tidepool in Pacific Grove.
26 October 2015
© Allison J. Gong

The sea hares are herbivores, and they continued to munch on red algae even when completely emersed. At one point I accidentally either stepped on or kicked one, because suddenly the water around my feet started turning purple. I looked around for the culprit and found a large sea hare (almost half a meter long) heading towards the depth of a pool, oozing huge amounts of purple ink. And by "oozing" I really mean spewing. It looked like a volcano shooting lava into the water:

Color me impressed! Here's the animal that made all the ink:

California sea hare (Aplysia californica) exuding ink. 26 October 2015 © Allison J. Gong
California sea hare (Aplysia californica) exuding ink.
26 October 2015
© Allison J. Gong

It was a good day for molluscs. I saw a couple of these little chitons, Chaetopleura gemma. They are only about 1.5 cm long, and the ones I've seen in the field are orange, often with one of the valves an entirely different color.

Chaetopleura gemma, a small chiton. 26 October 2015 © Allison J. Gong
Chaetopleura gemma, a small chiton.
26 October 2015
© Allison J. Gong

And there were some other chitons, too. This is a beautiful specimen of Katharina tunicata:

The black katy chiton (Katharina tunicata). 26 October 2015 © Allison J. Gong
Black katy chiton (Katharina tunicata).
26 October 2015
© Allison J. Gong

In this species the girdle, the tough lateral edges of the mantle extend dorsally to nearly cover the eight plates on the back. They are one of the easiest chitons to identify in the field because of this feature.

And on my way out I saw a large (~7 cm) mossy chiton, Mopalia muscosa. These chitons can be fairly abundant at the sites I visit; every time I see one it's like meeting up with an old friend.

Mossy chiton (Mopalia muscosa). 26 October 2015 © Allison J. Gong
Mossy chiton (Mopalia muscosa).
26 October 2015
© Allison J. Gong

I find chitons very interesting, maybe because they can be quite abundant and yet are often overlooked. Many of them look not too different from the rocks they live on, and they don't exactly lead the most active lives when we see them. However, if we were to spy on them at high tide, I bet we'd see a lot more action from chitons. And maybe it's the very stillness of chitons that make them so easily foulable by other organisms. The Mopalia in the photo is host to a lot of spirorbids (tiny polychaete worms that live in spiral calcareous tubes) and various algae.


The Great Tidepool holds a special place in the hearts of marine biologists in the Monterey Bay region because it is where Ed Ricketts did much of his collecting and formulating the ideas that would become the field of marine ecology. He was a gifted writer and I find that his books convey not just his understanding of the rocky intertidal, but an affection for the animals that live there. Scientists are often assumed to be rather cold, dispassionate people; Ed Ricketts proved otherwise. If you've never read any of Ricketts' writings, I recommend Between Pacific Tides, as well as the memoir that he wrote with his friend John Steinbeck, Log from the Sea of Cortez.

I want to be Ed Ricketts when I grow up.

 

1

So, those bits of Ectopleura crocea that I grabbed from the harbor on Monday are voracious eaters. I didn't feed them yesterday because I didn't have time and the students spent the afternoon looking at them in lab, and I hoped that they'd be alive today. Some of the stalks had dropped their hydranths (the distal part that bears the feeding tentacles, mouth, and reproductive gonophores) but most of them were alive and lovely. I had a nice fresh batch of brine shrimp all hatched out and ready to go and thought I'd see if the hydranths could eat them. Little did I know that this simple exercise would occupy most of my day.

I started by squirting some of the brine shrimp onto the hydranths, which for the most were pretty lackadaisical about catching them. Then I decided to feed them the mashed up brine shrimp that I'm still feeding the tiny Melibe and WOW! that did the trick! Maybe it was the scent of the macerated brine shrimp that triggered the feeding response. I was fascinated.

They are beautifully and unexpectedly animated animals.

After I watched them feed for a while, it seemed to me that the outer ring of tentacles catches and holds onto prey, while the prehensile manubrium swings around and brings the mouth into contact with the food. In the meantime, while all this brine shrimp catching is going on there are other larger crustaceans crawling all over the hydranths, even onto the tentacles, without getting stung. I think their exoskeletons must be thick enough not to be penetrated by the hydroid's cnidocytes (stinging cells).

Having discovered the trick to making the hydranths eat, I squirted brine shrimp mush on them and left them alone for about 20 minutes. When I came back they had eaten and I could see brine shrimp in their guts, so I gave them more. The feeding response was pretty much as vigorous as the first one had been. So I kept feeding them throughout the morning and early afternoon.

If I didn't have other things to do, I could watch these all day. I hope that if I can keep feeding them this much they will regrow their dropped hydranths. Although I'm not sure how realistic it is to think that I can go through this routine every day. And do I really need a few dozen more mouths to feed on a regular basis? I seem to accumulate animals like other women accumulate shoes. On the other hand, I don't expect the Ectopleura colonies to last long in the lab so even my "forever" relationship with these particular animals will likely be over in a week or so. I can probably keep up this level of effort for that long.

1

Tomorrow my students will be examining cnidarian diversity in lab, so early this morning I went to the harbor to collect hydroids. Or 'droids, as I refer to them. These are not the droids of Star Wars fame, such as C-3PO and R2D2, but rather colonial cnidarians. As such, they are made up of many iterated units (called zooids) connected by a shared gastrovascular cavity (GVC), or gut. Despite how weird it seems to most people, this sort of colonial lifestyle is not uncommon among marine invertebrates; it occurs in several other taxa as well, most notably the Anthozoa (sea amenones, corals, and others), Bryozoa (bryozoans such as Membranipora), and Urochordata (sea squirts).

On my various trips to the harbor over the past few months I've been keeping an eye out for 'droids, as I knew I'd need them. The one species I was glad to see getting established this summer is called Ectopleura crocea; it is one of the non-native members of the fouling community that shows up in harbors all along the California coast. It is a most beautiful animal, and quite conspicuous when it is present. This year I've seen it growing lustily on the docks, mussels, and any manmade object that has been marinating in the water for a while.

In situ it looks like this:

The hydroid Ectopleura crocea, at the Santa Cruz Yacht Harbor 19 October 2015 © Allison J. Gong
The hydroid Ectopleura crocea, at the Santa Cruz Yacht Harbor
19 October 2015
© Allison J. Gong

The stalks in this particular colony are 3.5-4 cm long. Each one of those tufts at the end of a stalk is a hydranth, the part of the zooid that bears the feeding tentacles and mouth. Hydroids are cnidarians and thus have stinging cells along their tentacles, which form a ring surrounding the mouth.

Ectopleura hydranths actually have two concentric rings of tentacles, with the mouth in the middle of the smaller ring. Between the tentacle rings there is a sort of empty space that is filled with reproductive structures called gonophores when the colony is preparing for sexual reproduction. In some hydroids gonophores release medusae, but in Ectopleura they release gametes. A given colony is either male or female, and any one of the hydranths can become reproductive and develop gonophores.

Hydroids are definitely animals whose beauty is better appreciated when observed under a microscope:

Hydranth of Ectopleura crocea 19 October 2015 © Allison J. Gong
Hydranth of Ectopleura crocea
19 October 2015
© Allison J. Gong

In the colonies of E. crocea that I've observed before, mature male gonophores are a solid white and female gonophores are pinkish. I collected three clumps of Ectopleura today, and none of the gonophores are mature. You can see why the common name for this animal is "pink mouth hydroid," as the mouth is borne on a pink tubular structure called a hypostome.

I've tried multiple times to grow this animal in the lab. There are some experiments on resource sharing in hydroids that I've been wanting to do for years but haven't yet found the right species to work with. In captivity Ectopleura eats well, then after several days all the hydranths drop off and the colonies die. I've never had success getting them to regrow their hydranths, either. So I bring them in for short periods and observe them up close while I can.

I always find that autumn is a tough season for me, in terms of maintaining enthusiasm and fascination with the world around me. I feel, like most creatures, that autumn is a time to hunker down and take it easy until the winter solstice, after which we'll be gaining daylight again instead of losing it. Even if we get blasted by El Niño storms in January and February, it will be easier for me to feel energized simply because the days will be getting longer.

However, even though I really want to hole up with books, tea, and knitting (hi, Junkies!) life goes on and I can't ignore the siren call of the natural world. This morning I went whale watching with some of my students. It was a class trip organized by the other instructor for the course, and almost all of my students came along. If you know me, you probably know that I have a history of horrendous seasickness. As in so awful that none of the OTC meds even touch it, and although I have tried some of the prescription meds they all make me so drowsy that I can't drive or even really stay awake.

It has been a good year for whale watching in Monterey Bay. Humpbacks have been everywhere the past several weeks, showing off all their acrobatic skills and lunge-feeding right off the beaches in Santa Cruz. So it really is a fantastic time to go whale watching, and since I had to go with my class I asked my doctor about other seasickness drugs to try. She gave me something that has worked for other people, including the pharmacist who filled my prescription, and although I've been burned before by the words, "Oh, this will work. You'll be fine!" hope springs eternal and I tried it. And by George, I think it worked! Not that the seas were bad at all, but I think that if I'd gone drug-free I would have been substantially less happy out there.

We did see whales, but for the most part they were pretty far away. They didn't spend much time at all on the surface, just a breath or two and then a show of the flukes as they dove to deeper water. The only breaches we saw were way off in the distance. There were a lot of common murres swimming around, which were extremely fun to watch. They are ecologically similar to penguins in the southern hemisphere and even resemble penguins, with their "tuxedo" plumage.

I was trying to photograph some murres on the surface when this happened:

Pair of common murres (Uria aalge) and a humpback whale (Megaptera novaenagliae) on Monterey Bay 16 October 2015 © Allison J. Gong
Pair of common murres (Uria aalge) and a humpback whale (Megaptera novaenagliae) on Monterey Bay
16 October 2015
© Allison J. Gong

Most of the murres scattered when the whale surfaced, and I was lucky to get even two of them in the frame.

We also saw a lot of pelicans.

Adult (white-headed) and juvenile brown pelicans (Pelecanus occidentalis) in Moss Landing Harbor 16 October 2015 © Allison J. Gong
Adult (white-headed) and juvenile brown pelicans (Pelecanus occidentalis) in Moss Landing Harbor
16 October 2015
© Allison J. Gong

Those browning lumpy things in the water at the top left of the photo? Those are sea otters.

And look at this!

Assorted wildlife covering a dock in Moss Landing Harbor 16 October 2015 © Allison J. Gong
Assorted wildlife covering a dock in Moss Landing Harbor
16 October 2015
© Allison J. Gong

The rocks in the background are covered with adult pelicans. The upper dock is occupied by Brandt's cormorants (Phalacrocorax penicillatus), which appear to require more personal space than do pelicans, and one of what I think is a great egret (Ardea alba). The lower dock is almost submerged by California sea lions (Zalophus californianus).

I'm counting today as a minor victory, and I'm grateful to have been able to enjoy it. This is the first time I've been out that far on Monterey and not wanted to die. 'Tis the season for gratitude, isn't it?

ORGANISM OF THE MONTH: Pugettia producta, the kelp crab

For a few months now, I've had a pet kelp crab running around in one of my seawater tables. I don't remember where I collected it, or even whether or not I collected it at all; quite often crabs and other animals arrive as hitch-hikers on kelp that we bring into the lab to feed urchins, and I end up with many cool critters in my care that way. However she got here, this crab has been rather a pain in the butt during her stay with me. For at least a couple of weeks she got stuck in the drain of the table and would not come out despite three experienced marine biologists (including yours truly) trying to persuade her by altering water flow and offering food bribes. Then she disappeared from the table drain and I assumed that she had gone all the way through to the floor drain, where she could live quite happily for all eternity. Then she suddenly showed up again in one of my urchin baskets. When she came back up from the drain and how long she'd been hiding, I'll never know.

Wondering why I keep referring to this crab as "she"? It's because I know for certain that she's a female. Here's the secret to how you can determine the sex of brachyuran crabs (most of the common crabs: kelp crabs, shore crabs, rock crabs, even Dungeness crabs): You look at the shape of the abdomen, which is curved forward on the underside of the body. See here:

Abdomen of female Pugettia producta. 16 October 2015. © Allison J. Gong
Abdomen of female kelp crab (Pugettia producta)
16 October 2015
© Allison J. Gong

The abdomen is the broad flat upside-down-U-shaped panel that covers about half the width of the ventral surface. Female crabs brood their embryos under the abdomen, hence the broad shape. Male crabs of the same species have a much narrower, pointed abdomen.

Since her escapade with the drain the crab has been more, shall we say, co-operative. She's still free to scurry around at will in the table, but I haven't found her doing anything objectionable such as tormenting urchins or trying to get down the drain again. She has also been eating well.

Until this past week, that is. On Monday she accepted a piece of food but then abandoned it without even tasting it. On Wednesday she fled from the food, which I took to mean that she was getting ready to molt. Like all arthropods, crustaceans molt their exoskeletons every so often. The decapod crustaceans I'm most familiar with tend to off their feed for a few days before molting, and usually the actual shedding of the exoskeleton occurs at night. Then we show up the next day and voilà! like magic there's a new, bigger crab in the table.

Ms. Kelp Crab stopped eating on Monday of this week. Today (Friday) I didn't get to the lab until about noon, and one thing I noticed in the table was an empty carapace. Sure enough, she had molted. It took a little hunting to find the crab herself, but she wasn't really hiding and her new exoskeleton had already hardened. I'm pretty sure she'll eat on Monday.

Kelp crab (Pugettia producta) and carapace of its molted exoskeleton. 16 October 2015 © Allison J. Gong
Kelp crab (Pugettia producta) and carapace of her molted exoskeleton
16 October 2015
© Allison J. Gong

Living in a rigid exoskeleton means that a crustacean can increase in body size only in the time period between when an old exoskeleton is shed and the new one hardens up. I'm always curious about exactly how much crabs grow when they molt. So today I measured the crab and her old carapace at the same place, halfway between the two points on the lateral edges of the carapace. Huzzah for empirical data! The old carapace measured 27.6mm across, and the new one 33.8mm, for an increase in width of 6.2mm or 22.5%. Mind you, this is simply the increase in one linear dimension of the crab's body. To obtain a more accurate measurement of body size increase, I'd have to have weighed the crab immediately before her molt and after it. Still, it does give an estimation of how much bigger a body part can get when a crab molts.

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. . . must come to an end, so they say. And Scott's and my little experiment growing Pisaster ochraceus came to its end when the last of our teensy stars gave up the ghost a week ago. We aren't entirely surprised, as nobody before us had succeeded in growing these guys in the post-larval stage, but it's still sad to see the empty paddle table and disappointing to know that we haven't really added to the body of knowledge about how to grow them.

But we did make a small bit of progress, at least to further our own understanding of exactly how difficult it is to do what we attempted. To summarize, here's a timeline of what we did and what happened:

  • 18 and 20 May 2015 -- Collected adult stars from local intertidal sites. Made up the solution of "magic juice" (100 µM 1-methyladenine).
  • 2 June 2015 -- Shot up stars with 1-MA. Got usable amounts of gametes from a total of three stars: 2 Purple (1 female + 1 male) and 1 Orange (female). After examining gametes to make sure they were okay, set up two matings: Purple x Purple; and Orange x Purple. The Purple x Purple embryos went through the earliest developmental stages just fine. The Orange x Purple embryos got off on the wrong foot and never recovered.
  • 5 June 2015 -- Purple x Purple embryos began undergoing gastrulation. Began feeding them. Orange x Purple embryos all dead.
  • 20 July 2015 (age 48 days) -- Larvae began settling.
  • 27 July 2015 (age 55 days) -- Counted a total of ~22 tiny stars in the jars. Removed a few to measure, and they were all 500 µm or smaller in diameter. It was very difficult keeping track of things this tiny in our 1-gallon jars.
  • 13 August 2015 (age 73 days) -- Paintbrushed out all of the little stars into a bowl and divvied them up into six food treatments. Replaced bowls in the paddle table to provide very gentle stirring.
  • 21 August - 7 September 2015 -- Stars died off in all but one of the food treatment bowls. By 7 September (age 96 days) the only surviving stars (N=4) were the ones we kept in a bowl with a small piece of mussel shell.
  • 11 September 2015 (age 100 days) -- And then there were three.
  • 28 September 2015 (age 117 days) -- Two survivors + 1 corpse.
  • 2 October 2015 (age 121 days) -- And then there were none.

In a nutshell, the larval development went fairly well, as we expected, and the post-larval survival sucked, also as we expected. We did manage to get those last two stars to survive 48 days post-metamorphosis, which is something. I'm not sure how much credit we can take for that, though, as I suspect that the reason the other juveniles died had to do with poor water quality as much as lack of food.

Here's what I think might have been going on: We are in our second consecutive year of elevated seawater temperature, and coupled with the massive El Nino that yesterday was proclaimed to be among the strongest ever this means that coastal animals are being subject to higher-than-normal temperatures. In ectothermic poikilotherms such as marine invertebrates, metabolic rate is directly related to environmental temperature. Thus, higher ambient seawater temperature should result, all else being equal, in a faster growth rate.

This sounds like it might be a good thing for the Pisaster larvae, especially if predation and other risks are higher in the planktonic larval stages than as benthic juveniles. However, I think there's more to the problem than simple growth rate. What if success as a juvenile depends not only on how quickly an animal progresses through all of its developmental stages, but also on how much time it spends in the different stages? For some larvae, notably the nauplius larva of barnacles, the primary job is to eat as much as possible and deposit energy reserves in the form of oil droplets; these food reserves will be utilized by the second larval stage, the non-feeding cyprid, as it hunts around for a place to establish a permanent home in the benthos. Perhaps part of the job of the developing Pisaster brachiolaria larvae is also to sequester energy reserves. Although no oil droplets were visible in any of the larvae that Scott and I observed this summer, energy could have been stored in other tissues of the larval body.

Back to the problem of post-larval survival. Our larvae began metamorphosing after only 48 days in the plankton. One of our sources has Pisaster ochraceus undergoing metamorphosis at 76-228 days in culture, at temperatures of about 12°C (for the duration of our experiment this summer ambient seawater temps were 15-18.5°C). So, if the warmer temperatures caused the larvae to develop more quickly than normal, and the larvae spent ~25 fewer days in the plankton than they "should" have, they may simply not have had time to accumulate whatever energy reserves they'd need to draw on once they metamorphosed.

That's just a guess on my part. I also imagine that poor water quality played a part in our juvenile stars' demise. It proved to be impossible to make potential food available to such tiny animals while keeping their water clean. We thought that stirring on the paddle table might help, and who knows, maybe it did.

In any case, RIP, little guys. Thanks for what you taught us, and I'm sorry we weren't able to help you succeed.

Juvenile Pisaster ochraceus, age 75 days. 16 August 2015 © Allison J. Gong
Juvenile Pisaster ochraceus, age 75 days.
16 August 2015
© Allison J. Gong

 

That cute little Melibe I found last week is still alive, and still super cute. It lost one of the two large cerata on its back the second day I had it, and I wasn't sure it would be able to survive long without it, but it has hung in there and started growing a replacement. This afternoon it was crawling on the underside of the surface tension in the bowl:

Melibe leonina crawling on underside of surface tension. 2 October 2015 © Allison J. Gong
Melibe leonina crawling on underside of surface tension.
2 October 2015
© Allison J. Gong

It is extremely difficult photographing transparent animals; this is the best shot I got. You are looking at the animal's ventral surfaces. It is using its elongate foot to stick to the surface, and the rest of the body is suspended from the foot. The oral hood is wide open and you can see the little blue spots at the base of each tentacle.

The best news is that the tiny Melibe has learned how to eat! The first couple of days I offered it live brine shrimp nauplii, and the Melibe didn't seem to like the thrashing of the nauplii. It cowered and shrank instead of trying to eat them. Then it occurred to me to mush up the nauplii first, so they wouldn't be so active. I also thought that the Melibe might be able to eat the mush itself. Aha, success! Except that I wasn't able to capture any video or photos then.

Today, though, the Melibe did this, while I had the camera all set up and ready to go:

Instead of cringing from the nauplii, today the Melibe was actively going after them. In this video it encloses its oral hood around a handful of nauplii and collapses the hood, forcing the nauplii into its mouth. You can actually see the nauplii stop struggling as they are ingested.

I think the Melibe is growing, too. I'll have time to measure it on Monday.

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