Taxicuticulary: Crustacean Shell Preservation

Dear Blue Lobster:

We have a blue lobster in our fish tank. The lobster just shed his shell. Is there a way to preserve the shell or at least the claws for our child to keep? Thank you.

Dear Gentle Sir:

Families often wish to remind themselves of the good times spent with their shelled friends and one way to do this is taxicuticulary, the preservation of their cray's shells.

The first step in shell preservation is cleaning. Using a 1:1 ratio mixture of distilled water and distilled vinegar, scrub the shell parts lightly with a toothbrush. When finished, rinse thouroughly in distilled water. Since vinegar is a weak acid, it will eat the shell if left too long.

After scrubbing, soak the shells in distilled water for twenty-four hours in a cool, dry place removed from direct sunlight. This will help dissolve any deposits on the shell. After twenty-four hours, place the shell on a clean towel to dry for several hours.

The third and final step should be performed by an adult. Take the dried shell and dip it in a clearcoat or varnish. The choice is yours whether you want something thin to simply coat the shell or something thicker. Call or visit your local home improvement store for more details. Tell them you're preserving crayfish shell and they ought to have a recommendation.

One caveat: if you intend to make jewelery, such as a nice pair of pincer earrings, drill the holes after the second step, then again once the lacquor or clearcoat has dried. This preserves the shell more effectively.

Good luck with your taxicuticulary project!

Growing Prawns in Kuala Lumpur

Dear Blue Lobster:

I accidentally came across your blog while searching for material on crayfish.

I really hope you can take the time to answer my mail, as I am really interested in raring prawn/ crustaceans (particularly crayfish) in Malaysia.

This would be a really novice question, would the American Crayfish be rared in a tropical climate ?

Kuala Lumpur has a hot, tropical climate with heavy rain storms occurring throughout the year, mostly in the early evenings. Day time temperatures can reach around 95°F (35°C).

What would be the best import species to be rared here ?

I have a piece of land, roughly 20 acres with a running stream in it, I am now really thinking hard to rear something in it.

What would your advise be if i wanted something crustaceans ?

Thank you in advance for your time,

Cheers,
Jack

Dear Gentle Sir:

Selamat pagi!

Since crayfish are ectothermic, or "cold-blooded," their climate does matter. Too hot of a climate for a crayfish can cause metabolic, nervous, and respiratory complications, putting a profitable harvest in jeopardy.

The name "American Crayfish" is problematic because it does not specify a species, but assuming that it is from a hot-humid region, where it's 20  for 3,000 or more hours annually and 23  for 1,500 hours annually, the cray ought to thrive.

This includes Orconectes rusticus, which is, of course, considered an Invasive Species Class 1, which means it is under the tightest control from environmental authorities due to its proclivity to disrupt native species.

Likewise, the Marmorkrebs clones itself so readily that, even though a tropical climate would be unideal for it, it would represent a very real and urgent danger to your area.

Check with your local authorities for their regulations regarding what species are legal to grow where you live. Optimally, they will have a list of known safe species and perhaps supplier contacts as well. You should be able to request an official decision on other species should you so desire.

Also be aware that, despite superficial similarities and local jargon, crayfish and prawns are not the same type of animal. A "prawn" is a lay term for freshwater shrimp of various classifications while "shrimp" seems reserved for marine species.

When considering and purchasing species for aquaculture, always demand binomial nomenclature and research its veracity. In unregulated markets, the switch-and-bait sale (no pun intended, of course) is dangerously common.

Too many times has an honest waterfarmer been taken by a deceptive fishmonger and later found his harvest of crustaceans to be all shell and shank, or the small wiggly larvae he purchased to create nothing but clouds of mosquitos. Do not share such an outcome with less educated entrepreneurs!

Milk: It Does a Body Shell Good?

Dear Blue Lobster:

I'm afraid my electric blue lobster ins't getting enough calcium, what should I feed him?

Dear Gentle Sir:

Crustaceans form their exoskeletons from chitin, a leathery carbohydrate reinforced with calcium carbonate.

Without the calcium carbonate, as happens just after a molt, a crustacean is considered "soft-shelled." Some crustaceans eat their old shells to regain a measure of calcium so as to harden themselves. In an aquarium, where that might not be tenable, what is one to do?

One solution that was popular in the Eighties was to add milk to the aquarium. This was at the height of the American Dairy Council's "Does a Body Good" campaign, when the dairy industry was trying to create new markets. They introduced "Milk-for-Fish" to the pet trade in 1985.

Unfortunately for crustaceans in American aquaria, milk in the water had several undesirable side-effects. First, milk is slighly acid, which sent the pH levels of tanks off. Second, crustaceans can only absorb calcium by ingestion, so passing milk through their gills did nothing but make them breathe lactose and milk fats all day long.

Third, it made the aquarium opaque, so humans couldn't see their small friends and their small friends could not see one another. Fourth, it interrupted crustaceans' antennae's sensory abilities, causing them to bump into their environment drunkenly and miss out on food entirely. And fifth, it turned the water rancid and quite stinky.

After a backlash from the aquarium community, in which several lawsuits claiming false advertising were launched and several out-of-court settlements were made, the American Dairy Council withdrew their Milk-for-Fish campaign.

Since then, "calc-licks," small lumps of compressed industrial chitin by-product, have been the product of choice for crustaceans in need of a calcium carbonate boost. They can be had from your local pet store quite cheaply depending on the size.

You can also feel free to add washed shell pieces from your own shellfish dinners, something much cheaper and closer to what a crustacean might find in front of them in the wild.

The Torturous Train of Triops Taxonomy

Dear Blue Lobster:

Can you tell me if any species of tadpole/longtail shrimp live in Taiwan? Thanks!

mj klein

Dear Gentle Sir:

The triop, also known as the horseshoe shrimp, lazarus shrimp, shield shrimp, tadpole shrimp, or, in Mandarin-speaking regions, as 盾蟹 (shield crab), are sixteen species between two genera under the Linnaean taxonomical system that comprise one of the oldest and most primitive crustacean groups still extant. They have not changed much in the last 220 million years.

The distribution of species is problematic in the historical context. One species, Triops longicaudatus, is distributed through central North America, all of South America, parts of Micronesia, and East Asia (though not Taiwan). Several theories have been put forth to explain such complex distributions, but each has serious flaws.

Paterson (1977) proposed a reclassifcation of extant triops species, suggesting that the distribution failed to make sense because the taxonomy was wrong. Marmur (1979) argued that the taxonomy was indeed sound but that closer study of prehistoric landmass movements was in order while Webb (1980) pushed for even more radical taxonomic reclassification.

Webb later concluded that triops were actually two species with pronounced climate adaptations causing subspeciation (1982) and made vigorous attempts at hybridization, though he sadly was committed later that year and never contributed to the topic again; Mitchell (1984) posited that the triops genera were the result of convergent evolution.

Molecular studies put an answer to the question with Capaldi (1988), who showed the lineages were quite accurate as understood. Since then other have quibbled over species and subspecies classification and discussed plate tectonics and its intersection with triops distribution.

In answer to your initial question, there are no species of triops in Taiwan, which offers a tantalizing clue to crustaceologists. Did triops never live on Taiwan, meaning the island separated from Asia before they existed? Or did triops live there for a time but, in the specialized island environment, go extinct?

Until these and other questions are answered, the multi-million year old mystery remains, tantalizing scientist and hobbyist alike. If you're desperate to see triops in Taiwan, however, try visiting some university labs, where imported speciments thrive happily. Just don't release any in the wild!

The Case of the Feathered Crayfish

Dear Blue Lobster:

I have a 3 year old Blue Lobster named Ozzy and he just molted and now he has these weird feather-like parasites growing off the side of him. They are an inch long. They were under his shell before he molted. They look like sea-corral and have feathered fans that look like they catch microorganisms.

I was wondering if an anti-bacteria / anti-fungal medication will work eventually. It has done nothing so far.

Do you know how to get rid of them without hurting Ozzy?

I attached a picture

Gary
Ontario, Canada

Dear Gentle Sir:

Those are no parasites, those are your crayfish's gills!

Sometimes, when a cray—or any crustacean—molts, the process goes awry. This can happen for a number of reasons, such as poor diet, improper habitat, distress, or unfavorable genetics. The process is torturous to begin with and is the most vulnerable part of any crustacean's life.

Of the many things that can go wrong during a molt, it is most common in crayfish for legs and antennae to become suppressed or mangled. Therefore it's possible in some crays for whole legs to grow underneath their shell though they remain unseen on the outside. Indeed this is how crays regenerate lost limbs.

Mismolting can result in other deformities as well, some of which can lead debilitation or death. Crayfish have been known to mismolt their tails, which means they can not escape by means of tailflapping, leaving them slow and liable to predation. A cray in a laboratory was recorded to have mismolted its eyes and spent the better part of two months blind, making it way by its sense of smell alone.

In your case, though your crayfish might look freakish and scare its other tankmates away, it will likely survive. Make sure your cray has plenty of available shelter and does not share its tank with any predacious species. If you suspect water quality being a factor in your cray's mismolt, have a batch tested at your local pet care center.

In the meantime, enjoy your cray's wonderful new plumage underwater and out of the air until the next time it molts, when the gills will hopefully become enshelled again.

Lazarus (Shrimp) in Israel?

Dear Blue Lobster:

I am getting ready to start growing triops with the kids.

Are you aware whether there are fossils of triops in Israel? Where could I go with the kids to see them?

Thank you,

Nathan Wirtschafter
Hashmonaim, Israel

Dear Gentle Sir:

Despite the term "Lazarus" used to describe triops, there are no triops fossils in Israel. One was discovered in Jordan in 1922 by Dr. Abraham Müller of the Freie Universität Berlin in strata some twenty-two million years old, though its species and genus were never verified.

Despite this dearth of triops fossila, a fun experience for your children can still be had due to the short lifecycle of the creatures. Simply order a triops kit from your favorite online retailer and follow the instructions. In the course of several months your children can chart the birth, life, death, and "fossilization" of their own triops.

In whatever container your grow your little friends, include a layer of clay or mud and sand at the bottom. Once the triops die, leave their tank in the sun until the substrate is completely dried. With a toothpick, paintbrush, and magnifying glass, your children can unearth the triops exoskeletons.

Just like a real paleontologist, carefully piece together shell fragments and any other items of interest. Can your children guess from the "fossils" alone what the creatures ate? How they moved? Reproduced? How did they breathe? Of course your children know these things from watching the creatures while alive, but looking back through the "fossil record" here will be a rewarding experience.

And of course, once finished with your dig site, add some water and watch triops hatch anew, just like the real Lazarus!

Will My Ten-Incher Get Bigger?

Dear Blue Lobster:

I bought a blue lobster from WalMart about 3 years ago. He is now about 10 inches long (tail to claw) and still growing. How big do these get?

Bill Schamp

Dear Gentle Sir:

Without knowing the species, it is hard to say. Typically, there are only two species sold at retail chains in North America: Orconectes immunis, which reaches around 14cm (5½ in.) or Procambarus alleni, which grows slightly largers at 15cm (6 in.). Since your cray is roughly twice the length, it is possible that it's an Australian variety, as Australian species often exhibit insular gigantism. Whether it's a Cherax destructor, fabulosis, quadricarinatus, or tenuimanus, or another less common species, it could easily grow upwards of 34.5cm (13½ in.).

Since your cray is quite large and will likely grow larger, you should have a twenty gallon tank at a minimum, if not twice that. Considering the better conditions the cray will recieve in your tank, and the possibility that there are growth-inducing chemicals present in the water itself (from birth control pills, industrial runoff, etc.), your cray would be safest in a one hundred gallon tank. This would allow him or her to grow to an impressive 45cm (almost 18 inches!) and still feel unstifled. You can also create quite the reproduction of a natural environment with the extra room, including logs, rocks, shallows, and substantial flora.

In the future, when asking for help regarding a specific cray, include some documentation that might help identification. This includes some photographs from different angles, especially the cray's underside, place and date of purchase, and the common or scientific names and any other information given at the store. One may be able to deduce from some of the less direct evidence what family or genus the cray is, if not the species. This can help make any advice regarding your cray more accurate and therefore more beneficial in the care of your little crustacean friend.