Posts Tagged ‘development’

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.

 

The Post – Admiral Byrd was NOT Worshipping Me or The Aquarium Light

February 11, 2008

Over the last 2 days my husband noticed that Admiral Byrd has been spending a LOT of time, meaning almost ALL of his time, up on top of the gravel hill or the decorative cave rock, or the live rock, or just about anywhere else in the tank, waving his claw. He looked so funny up on the cave rock. He seemed to be staring up at the aquarium tank light, waving his claw as if paying homage to a god. We figured either he held the aquarium light or my hand in high esteem.

My husband has joked that he thinks the crabs go inside the live rock so much because it’s actually their holy site. He thinks they’ve cobbled together a crude altar made of gravel and on the altar they’ve fashioned a shrimp pellet image of their deity, the hand that feeds them . . . basically mine. As he put it, imagine that every day a hand comes down out of the sky and places steak or shrimp or pancakes in front of us. That’s what it must be like every time my hand drops algae or shrimp pellets near them.

In any event we weren’t sure why Admiral Byrd decided to spend an entire day paying homage to me or the light. Why all of the sudden? There’s been nothing new going on in the tank otherwise, all three crabs have been actually pretty placid, out and about feeding, and generally happy. Was this some sort of designated crab “Holy Day” that just happens to coincide with Lent?

As it turns out, alas, neither the aquarium light nor my hand are the object of Admiral Byrd’s devotions. Melanie Hamilton is.

From the Fiddler Crab page on the Chesapeake Bay Program’s bay restoration site:

“When looking for a mate, he stands near the edge of the burrow, often alongside a string of other males and their (similarly well-maintained) burrows, while the females, returning from foraging, walk past. The male waves his large fiddler claw until he attracts the attention of an interested female, who then stares at him for a short period.. The male resumes his claw-waving, and if the female remains receptive, the male runs toward her, then runs back to his burrow, and repeats this motion several times until she either moves on or follows him to the burrow. ”

Apparently, mating behaviors take place not just when the female forages, but also when she molts. I happened to notice this pale, upside down body lying under the water filter this morning and immediately my heart hurt. I thought “Oh no! Melanie Hamilton died!” But not so. Looking closer, I saw that it was the pale ghost of Melanie Hamilton. It was that eerie translucent white, like Scarlett O’Hara’s was, though much more petite given that Melanie Hamilton is so dainty. Melanie Hamilton sat right behind it. I would have gotten pictures for this blog but she had tucked herself and her tiny ghost so far under the water filter that I could not get a shot. If only I had fiber optic cable, maybe I could get footage! I have concluded that the fiddler crabs have designated the “under the water filter space” as the “molting place.” All 3 have used it now. I think it has enough stretching room to shrug off the old shell, but is sheltered enough to keep everyone else away while their new shell hardens.

Admiral Byrd of course, was well aware of events in the tank. He was standing just a few inches from the water filter hoping to catch her eye. Alas, while Admiral Byrd is a true romantic and his efforts were truly heroic – I mean he has to be exhausted after almost 24-hours straight claw-waving – Melanie Hamilton is having none of it. She has turned her back on him and remains secluded under the water filter.

But anyway, the mystery is solved. Admiral Byrd doesn’t give a darn about the tank light or the hand that feeds him. He apparently can sense the approach of “molting” and was doing the crab Valentine’s Day equivalent of serenading his lady.

Sorry no pictures, though. I told my husband if he ever decides to spend money on expensive jewelry or clothes for me, I would prefer one of those borescopes like they use for colonoscopies. That would work GREAT in the tank for closeups of everybody! 🙂

Coming up this week:

Now that you’ve gotten to know me a bit – a cross between sea life maniac and soulful – I’ll start to introduce some of the projects I’m working on. I’ll share what I’ve done, what I’m doing and where I see myself going. Children’s writer and illustrator, Uri Shulevitz, described three stages of a writer’s development at a conference about 12 years ago. I’ve kept them as a kind of road map in my development and will use them to describe what I’m doing.

Also to come, a Writer’s bio page of what I’ve already written.

Happy Monday!