Since you bring it up I'm pretty sure mules are sterile. Hence they could never overtake the wild population or even reproduce at all.
What is wrong with hybrid shrimp?
- Thread starter jflng
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As crosses within the shrimp genera Caridina and Neocaridina should make clear, interspecific (interspecies) hybrids are not necessarily sterile. Note: crossing experiments with other animals (I don't know of any experiments or anecdotes for shrimp) have shown that even if the first few generations of hybrids are not sterile, genetic incompatibilities can cause health and fertility problems further along the line.
So exactly how can hybridization be undesirable?
Simply put: Hybridization can permanently destroy the unique character of species and their variants -- to swamp all their wonderfully distinct combinations of form, color, and behavior.
The fact that coydogs (the offspring of male coyotes, Canis latrans, and female domestic dogs, Canis lupus familiaris) are biologically possible doesn't make it desirable for them to supplant Fido. (Besides, such creatures -- often favoring their solitary coyote over their gregarious dog side -- have characteristically poor temperaments.)
The offspring of such crosses are no longer true-breeding (in shrimp, this often means color patterns that are radically inconsistent over successive generations). Remember -- recessive traits are completely masked in the first generation of hybrids and afterwards show up much less frequently than in the pure parent type. The coloration of hybrid shrimp is rarely a simple combination or 50-50 blend of ancestor tones and patterns -- the results are difficult to predict and often visually disappointing.
Apart from aesthetics, there are real ethical objections. Despite the popularity of mainstays like cherry shrimp, many species of freshwater shrimp are owned by relatively few people, and in very limited quantities. It would be foolish to contaminate breeding colonies of such shrimp with other species capable of hybridizing with them -- to reduce the captive numbers of a rare species to zero -- when native populations are increasingly imperiled. Pollution, flawed water management policies, and invasive species, among other factors, affect shrimp just as much as any other sort of freshwater organism.
As has already happened with some species of Rift Lake cichlids, aquarists may unfortunately find themselves caring for the world's only examples of shrimp that have gone extinct in the wild. In this case, allowing or preventing hybridization may mean the difference between preservation for future reintroduction ... and extinction.
You have enlightened me Cuvier. Thank you for that very in depth explanation. I now understand the concern given to crossbreeding shrimp. Your post should be a side note for prospective breeders of any animal.
I could probably bet that most respective parties have no real understanding why they side one way or the other on this issue. Many of those who say it’s wrong likely do not have this information at their disposal. Those who see no problems apparently do not understand the possible ramifications of such endeavors.
I still wonder however, given this information, would most still believe it’s wrong to hybridize species that aren’t on any sort of red list? If it’s found that pairing of two specific varieties produce healthy viable offspring, would there be any debate about it?
I saw this thread a while back: http://www.aquariacentral.com/forums/showthread.php?t=117904&highlight=gollies The OP crossbred mollies and guppies. All replies were positive. Going by this I guess it’s safe to conclude that hybridization is permitted when there are no foreseeable threats against the selected species populations. I’m sure guppies and mollies are safe everywhere from the captive varieties to their wild counterparts. There is probably even a market for gollies/muppies.
Years from now when there is a great abundance of several different shrimp species within the pet trade, will it then be acceptable to capitalize on shrimp hybrids?
I could probably bet that most respective parties have no real understanding why they side one way or the other on this issue. Many of those who say it’s wrong likely do not have this information at their disposal. Those who see no problems apparently do not understand the possible ramifications of such endeavors.
I still wonder however, given this information, would most still believe it’s wrong to hybridize species that aren’t on any sort of red list? If it’s found that pairing of two specific varieties produce healthy viable offspring, would there be any debate about it?
I saw this thread a while back: http://www.aquariacentral.com/forums/showthread.php?t=117904&highlight=gollies The OP crossbred mollies and guppies. All replies were positive. Going by this I guess it’s safe to conclude that hybridization is permitted when there are no foreseeable threats against the selected species populations. I’m sure guppies and mollies are safe everywhere from the captive varieties to their wild counterparts. There is probably even a market for gollies/muppies.
Years from now when there is a great abundance of several different shrimp species within the pet trade, will it then be acceptable to capitalize on shrimp hybrids?
I agree hybrids are a problem, I only brought it up to answer the first comment on shrimp vs. mule.
