Posts Tagged ‘pinpoint’

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 🙂 ).

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.

 

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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? 🙂

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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!

The Post – Caring, is catchy

January 30, 2008

Probably the most interesting thing in the fiddler crab experiment is my family’s reaction to them. My son came home from college at Christmas and initially looked at me like I was crazy because I talked so much about the crabs. In fact, my independent college student complained I was paying more attention to the fiddler crabs. He kept laughing at me as I talked to the crustaceans in that high-pitched mommy voice previously reserved for my toddler son and pet poodles. My husband just kept teasing me about the total amount we were up to on fiddler crab expenditures.

Within of day of being home, my son started watching them, and within a few days he was keeping track of who was doing what and telling me to check on Melanie Hamilton or Rhett Butler. In fact, I think he was the one who first noticed that Rhett Butler was dead.

My husband was the one who spotted Scarlett O’Hara molting and eagerly called me over to see her when I came in from grocery shopping. Last night, he came in from work and before he even said hello to me he stopped, peered in the tank and said with great concern, “There’s something wrong with Admiral Byrd! I think he’s dead!” As it turned out (after I poked Admiral Byrd with my latest acquisition, a 25 cc plastic pipette and bulb from Science Safari that I use to siphon out excess food), I think Admiral Byrd was just sleeping – they kind of hang there, their claws floating above their heads, and don’t react to much. But my husband walked away and said very seriously, “I think you’d better keep an eye on him.”

What I realized is that caring, like a cold, is an occupational hazard of sharing space. When you share space, even with a creature who has a brain the size of a pinpoint, it starts to get personal. When it’s personal, you start to care, even when you didn’t mean to.

I think the same thing happens with people. So often you hear people say, “I don’t like this group or that.” Then they meet someone from that group and find out they really are okay . . . maybe even . . . nice. It’s hard to share space – sit across the table from someone, hear their humanness, see it in their eyes – and not care. That’s the real risk factor I suspect . . . contact . . . sharing space. The minute you share the space, you start to see the real person. Once that happens, it’s personal. And once it’s personal, you’re done for because caring is catchy.