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.