Posts Tagged ‘larval’

The Post – Admiral Byrd is Peeking & New Aquarium Products

March 12, 2008

Some Fiddler Updates – New Product Technical Details and Romance

1) Preparations, Take 2, for the Fiddler Crab Nursery Tank:

I came home from PetsMart yesterday armed with calcium sand to replace the gravel in the nursery aquarium. That project will commence later today. The sand is actually something called Seachem Meridian Tidal Marine Substrate. It’s basically calcium carbonate precipitated from ocean waters by coral. It will stabilize the calcium and alkalinity levels in the water, and keep the pH from getting too low. Its porous structure and size supposedly are good for the growth of denitrifying bacteria. We shall see.

At the very least, it’s a dual purpose as I can also use this sand for the bottom of the land hermit crab cage I just bought. The land hermit crab project will be ramping up soon.

I also picked up some liquid food that should work fine for the larvae. I’d mentioned a product called JBL Nobilfluid that a gentleman from Finland used to raise his crab larvae. However the Nobilfluid is made in Germany and appears to be available in Finland, Germany, England, Italy and the UK, but I couldn’t tell if it was available here in the US. I could get it from a UK website but between the exchange rate and the shipping, I expect the cost is prohibitive. A JBL representative answered my email yesterday and said their product is not available in the US yet.

I found this new product at PetsMart called Kent Marine ZooPlex. The problem I had with the fiddler babies was trying to find liquid plankton to feed them. My mistake was getting live liquid phytoplankton, which made the tank toxic and killed them. I realized larval crabs need zooplankton, which is animal plankton = roughly translated: MEAT. Phytoplankton, being plant based, is the wrong plankton. Larval crabs are carnivores, not vegetarians. Anyway, Kent Marine ZooPlex is “concentrated aquacultured Marine Zooplankton” and is geared toward invertebrates including larvae. The bottle notes it can be used as a brine shrimp replacement. So this sounds like it might be just the thing for liquid feeding of newborn larval crabs who are too small to chase live brine shrimp around.

I will still need to get the dried brine shrimp eggs to hatch when I know I have a pregnant female ready to shed her eggs. The brine shrimp hatchery project will come a bit later.

2) How to raise the alkalinity of the water for the brackish tank without raising the pH?

The dilemma I have when using Instant Ocean to make up the brackish tank water for the adult crabs, is that I have to use it at about half strength. That way I get a salinity of about 1.010 instead of 1.020-1.024. The trouble is, that makes the alkalinity way too low meaning there’s not enough calcium in the water for the crabs when they molt.

I’ve tried adding Seachem’s Marine Buffer, to raise the alkalinity and it’s very successful, but it also raises the pH way up to 8.3. That’s fine for a marine tank, but for the brackish tank, the fiddler crabs seem to like the pH closer to 7.8-8.0 I have a constant battle trying to get the salinity low enough, the alkalinity high enough and the pH “just right” somewhere between a freshwater tank and a marine tank. When I use the Marine Buffer I have to then add something to lower to pH.

I was hoping to find something that would raise the alkalinity, but not the pH when I use Instant Ocean to make up the brackish water. Yesterday I came across Seachem’s Reef Calcium. The website description reads:

Reef Calciumβ„’ is a concentrated (50,000 mg/L) bioavailable polygluconate complexed calcium intended to maintain calcium in the reef aquarium without altering pH.”

I am going to try the Reef Calcium product and see if that solves the problem. I will let you know.

3) Romance: a humorous update for a Wednesday:

Ever since his success with Scarlett O’Hara, Admiral Byrd has been out there claw-waving up a storm. Melanie Hamilton spends just about all her time inside the live rock. Yesterday afternoon is the first time I’ve seen her out of it in weeks. I think she took to hiding out in the rock when Scarlett O’Hara was living in the nursery tank. With Scarlett temporarily gone, Melanie was the total focus for Admiral Byrd. I don’t think she liked that.

Anyway, after giving birth, Scarlett O’Hara has been eating almost non-stop. I think she finally slowed up a bit yesterday, but she’s still pretty ravenous. In fact yesterday, I dropped a shrimp pellet in the tank and Scarlett scrambled up and caught the thing in mid-drop. It never even touched down on the gravel. And she’s pretty good. No fumbling and bobbling the shrimp pellet. She spotted it, she jumped, clutched it to her chest and landed on her feet, eating the pellet before she landed. She could probably earn a spot as an outfielder for the Red Sox.

Unlike Melanie Hamilton, Scarlett hasn’t been too concerned one way or another with Admiral Byrd’s where-abouts. She doesn’t run from him, or toward him. She just eats. Still, I don’t think she’s averse to his presence as she’s spent a fair bit of time in his lair, the fake rock cave, while he walks around waving his claw. I have to wonder if he realizes she’s sitting in his house?

Last night I turned off the tank lights, shut off all the house lights and went upstairs to bed. A little later I had to come downstairs for something and walked by the tank. Even in the dark, I could see Admiral Byrd standing there on his gravel hill, waving his claw. Total darkness, but the crab is still out there trying to get the attention of the ladies of the tank. What dedication.

He is also very funny in his pursuit of Scarlett O’Hara. He climbs to the top of the live rock, to wave his claw of course. Yesterday while claw-waving, he caught sight of Scarlett down on the gravel next to the live rock. He stopped waving, tip-toed to the edge of the rock, peeked over the edge at her to see which way she was going, then, like a teenage boy in love, scrambled down the rock and followed her around all the while waving his claw.

So watch out Scarlett, Admiral Byrd is peeking.

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The Post – What to Feed the Babies and How Salty Should the Water Be?

March 1, 2008

Just a reminder that coming up over the next week, the next few installments on the journey of my Under the Pier novel. I had to take a break from those for taxes, actually finishing some more chapter revisions, and of course, taking care of the “grandchildren.” But stay tuned. More to come on Under the Pier.

Re the grandchildren:

What wonderful goings on! Soooo many little black dots in the nursery and they are definitely swimming around. Many are hiding out in the shadows of the live rock caves. So tiny and already they know to hide and avoid “predators.”

I am feeding them three times a day with a mixture of ground up mini-freeze dried krill, some ground up flake food, a few drops of the liquid Small Fry baby fish food, and a little distilled water mixed in. We shall see how it goes. And no, I am not grinding the mini-krill with my husband’s lovely stone mortar and pestle that he uses for grinding up herbs and spices in the kitchen!!

Regarding salinity – it’s a tricky call. While Uca minax, which are the type of fiddler crabs I have, are seen furthest up the estuary in areas of lowest salinity, there seems to be evidence that for at least the first two weeks of their larval development (zoeae) , they actually survive and do better at a higher salinity. However there is also evidence that for the next (megalopae) stage to metamorphose into crab Stage 1, this species does best with the lower salinity seen in the upper estuary environment that the adults live in. I will post more information tomorrow including the links to the two papers I found today on this subject. Long story short today though, is that zoeae of all the species of fiddler crabs, seem to need a couple weeks of “being at sea,” hence higher salinity.

I’ll also explain about the three species used in one of the studies and how their selectivity for salinity levels puts them in different spots in the estuaries and thus probably keeps them from competing with each other for resources and food.

Also to come – I dug out the small microscope I had as a kid and will pick up some microscope slides. So to follow, descriptions of babies, under the glass.

A couple of other notes – courtesy again of my engineer husband. He noted a bunch of white things all over the gravel and wondered if the babies had already molted. Maybe they have but these white dots were too big and irregular in size for baby shells. I believe it’s salt crystals that didn’t dissolve in the water before I added it. I added more water to bring the salinity up closer to a marine environment. I started at 1.010 (brackish) when they were born and over the course of yesterday raised the salinity first to 1.012, then by last night 1.015. Today I’ll finish raising it to 1.020. Then in two weeks I’ll bring it back down to 1.010-1.012, the optimal range for Uca minax adults.

Sand. Again, my husband was watching the babies swim – it is amazing to see these tiny things whiz around the tank – but he shined a light to see if they would follow the beam. The article I posted in yesterday’s gift mentioned that the babies will go to the light. My husband didn’t see evidence of that, but what he noted was that many little babies had worked their way down between the gravel bits, all the way down to the bottom of the tank. Unless they figure out how to get back up to the water, they’ve had it. Now let’s face it. Their parents had a brain the size of a pinpoint. How large a brain do you thing babies the size of a pinpoint have? So the odds of them getting back to the surface are not good. I said “evolution at work. Anybody who tunnels down in the gravel probably won’t live to reproduce. ” My husband noted that gravel is less than optimal for this (engineers talk like this by the way, things are optimal, less than optimal, sub-optimal πŸ™‚ ).

The real important point though was his next comment: “The NEXT time we do this, we should use sand.” There you have it folks. My husband has fallen in love with the fiddler crabs. In all truth, he has. He watches them, thinks about how to make their lives better, anticipates the babies getting ground up in the water filter…..those babies are lucky to have him!!!

Anyway, stay tuned for the links on those two articles about optimal (yes, OPTIMAL) salinity levels for fiddler crab larvae.

 

The Post – Nursery Update, Ethics, Parenthood, Friendship, and Just Being a Mere Mortal

February 25, 2008

Just a quick note this morning as I’m on the run. The next installment of my author journey is partially written. Those take me a bit more time. Pondering, reflecting, remembering. Lots to sift through. So those will resume this week.

For now, just to update – Scarlett O’Hara is still alive in the new tank – the “nursery.” Frankly, I was worried. I’d have felt better if I’d set that tank up last week and it had a week to run and settle out. I just hadn’t come to the point of “embracing” trying to raise larval crabs and when I did finally decide this weekend to try, it seemed like birth was imminent. Kind of a go/no-go response needed to be made ASAP.

Last night she just wouldn’t settle down in the new tank. Kept running back and forth, kept trying to climb the sides of the tank. Was there something wrong with the water that was hurting her? All the parameters looked great, in fact the water in the new tank was better than the original – that one’s overdue for a water exchange and the nitrites and nitrates in that tank are rising. So this one is actually healthier. However, certainly there’s other parameters I can’t measure. So my worry was that I’d put her in something I thought was better for her, but maybe I was killing her and couldn’t tell?

I wondered if she was just disoriented and couldn’t find a place to climb out of the water to get air. I noticed air bubbles escaping from her mouth at one point and was afraid she would “drown.” She has this lovely live rock with all kinds of crevices she could hide in, better than her old live rock, AND it’s much bigger so she can climb on top of it, but I thought that maybe in her stress she couldn’t find it. So I scooped extra gravel out of the original tank and put it in the new one and built her two gravel hills so she could walk up the hill and be partly out of water. She found them, but that didn’t seem to be the problem. She just kept running back and forth and climbing the walls.

My husband wondered if she simply couldn’t understand why the sides of this tank were so clean and where was all the microscopic algae she likes to eat? The other tank, though the glass sides look clear, apparently have microscopic algae on them because the crabs are always “picking stuff off” the sides and eating it.

Or maybe she was just so stressed out, she couldn’t relax and would kill herself with exhaustion?

I also noted last night that the formerly clear water in the new tank was now cloudy. I was convinced something awful was taking hold and maybe the live rock had something bad in it. If so, you would expect the nitrites to be rising. I repeated all parameters last night and the water looked good.

So by this point, who is more stressed? Her or me?

My husband said little, just said “It’ll be what it’ll be. You’ve done all you can.” I told him it’s not easy being “God.” He patted my back and said “At least not a God who cares.”

Anyway, I struggled with “should I just bag this whole thing and put her back in the original tank?” I decided not to add any more stress to her by moving her back. One of those – just let it go and see what happens, moments.

This morning the tank looks less cloudy. My husband said he came down and she was sitting quietly in the water, “tending” to her egg mass – ie – giving it pushes and pokes, as if turning them. When I came down, she had found her way to the top of the live rock and was just sitting there on top of her world, soaking up heat from the lights and appearing totally relaxed. (Or is she dead? Should I poke her? πŸ™‚ Just kidding).

All joking aside about my being so worried, I guess I felt guilty. As I said to my husband – Did I put her at risk of dying because I so wanted to try and raise the babies? Did my ego cause harm in this and should I have just left it all alone?

The ethical questions are never clear or easily answered. It’s like being a parent. You try your best, knowing that even when you do, you don’t know if you’ve made the right choices. And in your less than perfect moments, and we all have them, you wonder, will they be okay? Why does God entrust such a big job to mere mortals?

I think Lee Woodruff’s final comments in her book, In An Instant, apply here, at least for being parents, maybe not for being God to fiddler crabs. She worried about how her kids were affected by all the turmoil and intensity when her reporter husband, Bob, was in the hospital with a head injury. She had to be away for long periods to be with him. Things were in an upheaval even though family and friends were looking after things. I so loved her observations, because they are the truth. In thanking her kids she added:

“May you always remember that there are no perfect parents, just mothers and fathers doing the very best they can. And there are no perfect spouses either, just those who love each other enough to stand by “for better or worse.” Don’t be fooled: that kind of endurance is, perhaps, the greatest expression of love.”

I think she could only come to that lesson because of the messiness of life. I think it’s the messy low moments that teach us the most about being human, and about understanding the “human moments” in others. Those times teach us about being compassionate to ourselves and to others, especially when life is at its least pretty. We all want to look like we’ve got it together. Sometimes we do. Sometimes we don’t. Life gets messy. Thomas Moore, a former Catholic monk, in his book, Care of the Soul, I book I read, reread, dog-ear, highlight…in three different colors, quotes something from the Renaissance humanist Erasmus, that applies. Erasmus wrote in his book, The Praise of Folly, that “people are joined in friendship through their foolishness. Community cannot be sustained at too high a level. It thrives in the valleys of the soul rather than in the heights of spirit.”

So, from one very imperfect human, friend, wife, mother, fiddler crab God, go gently into your Monday. It’s really okay, no matter how it goes.

The Post – Is Birth Imminent?

February 24, 2008

I will be returning soon to the evolution of my novel, Under the Pier, but given the goings-on here, I have to take some time to tell of events unfolding in the fiddler crab world.

I decided to see if it is possible to raise at least a few of Scarlett O’Hara’s and Admiral Byrd’s babies, should they survive birth. It’s a long shot, but I want to try. Scarlett looked really pregnant yesterday – that abdomen of hers is large and when she pushes at it, it’s like jelly. I have these observations again from my husband.

It is TRUE LOVE when your husband acts as midwife for your pregnant fiddler crab, keeping close eye on her while I ran out today to get a chunk of live rock for the aquarium. He even called me on my cell phone at the aquarium store to tell me that Scarlett was picking at the larval mass, pulling out a brown thread here and there and planting it in the gravel. He felt birth was getting close and I should hurry home with the live rock. I tell you, is that a friend or not? How many people would call you on your cell phone to let you know your fiddler crab is getting ready to deliver? πŸ™‚

To back up, we went to Petsmart last night and picked up a new 10-gallon aquarium, tank top, light, light bulb, thermometer….. yes, another whole set-up. My husband is laughing but then, he is a geek, just one with different interests, so he respects this endeavor I’m involved in.

In fact, he is working on setting up his own blog that will have all kinds of tweaky things that reflect his interests. When it’s up and running, I’ll be sure to mention it. He finds the most unusual and interesting things out there. To give you a sample of the man, when we are out on a date it is not unusual to walk through the parking lot and have him explain to me the mechanisms for the inner workings of car backup lights and such. I just love it. Going somewhere with him is always interesting and an adventure. Sometime I’ll have to share how he and I hunted down the overgrown boarded up command bunker for a former Nike missile launch site in Newport News VA. πŸ™‚ But a story for another time. Those are the kinds of dates I love. Anyway, I’ll let you know when his geek site is up and running.

To get back to fiddlers, I spent last night setting up the tank. This time I started with distilled water. We have a small water distiller and I proceeded to use up our drinking supply to make up salt water for the “nursery tank.” Mixed up Instant Ocean powder in the distilled water, set up the filter, and within a couple of hours, got the water parameters just about where I wanted them: pH 7.8, alkalinity 180, hardness >300, chlorine, Nitrite, and nitrates all zero. Salinity was about 1.008, a little lower than I wanted because I want this tank’s water to be an almost exact match for the main tank.

This morning I used some marine buffer to bump the pH up to 8.0 and alkalinity closer to 300. Added a bit more Instant Ocean to get the salinity up to 1.010. I seeded the new filter with a strip of “very well colonized” filter material from the old tank to jump start the nitrogen cycle, and brought home from Fish Pros the MOST amazing chunk of live rock – ALREADY had all kinds of marine invertebrates and microscopic algae on it because it had been in another tank that had just been dis-assembled. So, the live rock is well underway growing organisms and probably has another dose of nitrogen-fixing bacteria ready to go.

I debated about what to do with Scarlett O’Hara, leave her in the old tank and struggle with where to release her babies or put her in the new tank with plenty of room for all. Finally decided to take a chance and I’ve moved her into the new tank. She seems to be doing okay in spite of being rattled by being moved. I’m hoping it didn’t disturb her too much. It always shakes them up a bit to move them around. I have done my best to make her a good nursery and here she is free from Admiral Byrd’s claw-waving. I even took the heater from the old tank and gave it to her in the new one. I ordered a new heater for the main tank which should be here Wed. But I figured Melanie Hamilton and Admiral Byrd will be fine for a couple days with the tank lights to keep them warm. I figured “momma” needed it more.

By the way, the tank heater I use is a small one geared for 3 gal aquariums. It’s pre-set and can be mounted sideways with suction cups, and there’s no risk if it touches the gravel. It’s a Marineland Shatterproof Heater (10 watts) part number VTMD10 and found it online at That Pet Place.Β  Since my tanks are only a third full of water (to allow space for the crabs to get out in air), regular heaters won’t work. Not enough water for them to be fully submerged. And regular heaters are generally large and have to be vertical.Β  This guy is short and can be sideways. Keeps the tank in the range of about 78-80 degrees F. So for what it’s worth.

So…the nursery is up and running. So very much hoping that 1) Scarlett will do okay in the new tank; I would feel terrible if she doesn’t make it because of the move 2) the babies do okay.

Then all we have to worry about is how to sell off many many many many many grandchildren? πŸ™‚ I’ll keep you posted.

By the way, if you want to have a few seconds of just staring at some nice marine creatures swimming amidst coral, click on the Instant Ocean link above. Neat intro.

The Post – How Long Do Fiddler Crabs Stay Pregnant?

February 23, 2008

I spotted this question on a Google search and decided to follow up on it. It has been the question in our house – Scarlett O’Hara seems to get bigger every day with the larval crabs she’s carrying. How long will she carry them? What will she do with them? I’ve learned that female fiddler crabs usually like to hang on to the babies until the right set of tides and conditions so that their babies will be carried out to the open ocean. Apparently they do this because the larval crabs stand a better chance of finding food, and of not becoming someone else’s food, out in the open ocean. That gives them the best chances for reaching adulthood.

The question in our minds here is: we have no outgoing ocean tides in the “aquarium estuary” so when will she release them?

We’ve noticed she keeps hanging out on top of the water filter. In fact yesterday she was deep down INSIDE the water filter. She’s also been ripping the filter backing apart and eating whatever she’s pulling off the fibers. Since fiddler crabs like to eat a lot of microscopic algae, I assume that’s what she’s found. I keep wondering though, is she going to release her babies in the “currents of the water filter?” If so, I wonder how she will decide which currents are “outgoing tide” to that imaginary open ocean we don’t have. πŸ™‚

Anyway, two good articles I came across in my search:

1) When ‘in a pinch’ won’t do: Ultra-picky female fiddler crab cited in UCSD (Univ of California at San Diego) study.

Apparently the female California fiddler crabs are VERY picky about their mates and have REALLY high standards for what kind of “house” the male is offering them. On average the female passes up 23 offers before finally selecting a male. In one case a female passed up 106 offers before choosing her mate. Now…I don’t know who to be more impressed with – the female fiddler crab who passed on 106 males before choosing one? Or the human researcher who followed this female fiddler crab around and kept track of how many males she turned down before choosing? In any event, an interesting article on the life cycle habits of the California fiddler crab.

2) The SC and C FAQ Database: it has a large number of questions and answers about crabs, shrimp, and crayfish. Question # 16 is about 3 pregnant female fiddler crabs and how long their gestation period lasts. Apparently in an aquarium, the female will release the eggs in about a week. We shall see. …Also it has information on what to feed the newly released babies, which might actually let them survive in an aquarium and grow to adults. Hmmmm 100,000 grandchildren. Needless to say my husband is thrilled with the news we might actually be able to help the babies survive in a tank! πŸ™‚ Now all I need to do is find micro-plankton, like Infusoria, to feed to them…..

The Post – Pregnant Scarlett O’Hara and the Proud Father

February 21, 2008

I am going to be out of the office today, so a brief, fun posting with pictures of pregnant Scarlett O’Hara carrying her larval fiddler crab babies. Also a shot or two of the proud father, Admiral Byrd, who is STILL waving his claw. I am determined to get a really good shot of him doing that claw wave, but these aren’t too bad.

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Here are some shots of “the babies.” They are the brown mass of egg-looking things tucked in that shelf on her abdomen. They’re not the sharpest shots, but then, Scarlett O’Hara is not the most cooperative super-model. She won’t stand still. Also, it’s hard to get a shot where she’s not moving her claws. She is CONSTANTLY shoving food in her mouth – she is a two-fisted, non-stop eater. I guess though, she is eating for a few thousand? πŸ™‚

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Admiral Byrd spots me and tries to hide in the corner of the tank against the live rock. The grayish streak is the silicone sealant in corner of the tank. I think he likes to hide behind that strip and also the thermometer strip (not seen) because it blocks his vision of me – that whole “if he can’t see me, then I don’t exist and he’s safe,” mentality? What do you want from a creature with a brain the size of a pinpoint?

The other two pictures are classic Admiral Byrd poses. He sometimes spends all day with his large claw in the air, sometime both claws in the air. While I know he’s either trying to scare me off or encourage the ladies, sometimes when he has both claws up, he looks like he’s paying homage to the god of the tank, the aquarium light above. He is also very pragmatic when trying to show off for the ladies. He’ll have his large claw up to get their attention, while using his smaller claw to shove food in his mouth. A guy has to eat, right?

See you tomorrow!