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Why cull shrimp?

5K views 24 replies 15 participants last post by  Silmarwen 
#1 ·
An honest questing I'm not looking into the morals etc.

I know a lot of breeders cull poorly coloured stock, is this due to bad genes or just a less than ideal colour?

I was thinking about it this morning, in my family almost everyone has black hair, however my uncle and myself have red hair, but still produce dark haired children. I know from breeding guppies that recessive genes will often spring up, only to last one or two generations. Do you get the same with shrimp, or will "culls" only produce more of the same?
 
#2 ·
Unless I'm mistaken, the culls are the dark haired people in your family (the normal color people, or dull colored shrimp). If you and your uncle were separated from the group and given red haired women, then repeat with the offspring in an attempt to create an all red haired family.
 
#6 ·
It could be any trait, it's just to clean up the genes so that the ones that aren't disireable don't show up in later generations. Also when we use the term cull, we sometimes don't mean to kill them off, we just remove them from our breeding population.
 
#7 ·
That's what I do at the moment, and just sell the less colourful shrimp as lower grade.

Growing up in a semi rural area I always assumed culling to be killing, it's good to know they are not being popped off for not looking perfect. I know I will probably be seen as a bit soft for this but I see it as a bit harsh to kill mine off when I can just as easily re-home them.
 
#9 ·
Culls will always have a home in the RAOK section too :) Myself for example - I have two tanks and wanted shrimp in both. Don't want a breeding program and don't intend to cull anything or enforce any specific trait - just wanted a handful of rejects from people who are trying to do these things.

They end up with perfect Painted Fire Reds and CRS that are almost all white - I get nice 'just plain red' and CRS with bands of white and red, exactly what I wanted for 'pets'

:)


Culls could also be used as feeders for fish, but I don't think anyone offering "culls from my breeding program for the cost of shipping" would ever have to wait long in the ROAK room!
 
#11 ·
I too was unfamiliar with the purpose of culling until I started breeding PFR's. I had one female with a flaw in her carapice. On either side of her head, she had a muddled spot that looked almost transparent compared to her rich red body. I mistakenly didn't cull her, and i found the same flaw in about 20 shrimp down the road. I had about 20 berried females in the tank, and thats not to say that she didnt produce any high quality offspring (there would be no way to know), but it took me a very long time to grow out those offspring to find their flaws and remove that gene. Just my two pence. :)
 
#15 ·
Culling isn't always about promoting/removing specific genetic traits either.

Shrimp, fish or otherwise, there's also culling to re-balance gender ratios, remove aging or debilitated specimens and to decrease overall numbers to improve resource availability for the remaining population.
 
#19 ·
Let's face it. Shrimp in general breed so fast and have so many offspring, and because we have taken away natural predators that keep their number down, WE are now the necessary evil that needs to keep numbers down in whatever way we decide to do it.

In the perfect conditions, a female shrimp can have 30 eggs fertilized (30 babies) every month. That's 360 yr.

No consider maybe half in a batch are female= 15 shrimp in one batch x 30 babies= 450 babies

Now after 3 months, each batch is mature= ####

### + ### + ### + ### etc

Okay, I'm too lazy to work out the math, but as you can see it is easily thousands of shrimp. Keep the best, cull the rest.
 
#20 ·
I don't keep shrimp yet, but I've heard talk of using culls as fauna in nano tanks, plus I'd likely just feed them to larger fish if populations start getting out of control. Keep the super-pretty ones to look at, and return the rest to the natural circle of life. The additional benefit of culling your own shrimp to use as feeders is that you know the water they came from, and you can be sure that there will be no problems with disease.
 
#22 ·
Exactly :) If I start breeding shrimp, honestly it will more be out of need for feeder shrimp than anything else, haha.
 
#24 ·
I'm one of those using culls in my micro tanks (think 1g down to 1cup) and-- despite putting them in conditions that I wasn't sure they'd even survive in-- I'm now finding myself having to cull again: I've got berried females in two of my smaller vases and with so little volume I can't afford to add to the load.

While I understand the fascination with brightly colored shrimp, culls are sadly underestimated. For most of my tanks, amanos and ghosts can get too big and too obnoxious, and high grade dwarfs would *detract* from the natural layout. Tiny dwarf culls--brown or greenish, lightly spotted, transparent or nearly so---are perfect. I can have a whole swarm of 'em tucked unobtrusively away in the underbrush picking away at algae and debris, merrily doing their jobs and providing the occasional live treat for my larger fish. It's fun seeing what variants are thrown as well--pretty amazing what can happen when you just let 'em go wild.
 
#25 ·
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