# 'Opae 'oeha'a



## cousinkenni (Jan 24, 2005)

Here is the second native shrimp-like crustacean found in the freshwater streams of Hawaii.

This guy's name is _Macrobrachium grandimanus_.........I believe named for the single large claw that causes the shrimp to walk funny. Unfortunaltely this guy is still real young so it hasn't had time to truly develop the large claw. Unlike the bisulcata, this guy is usually found in the lower reaches of the treams (they aren't good at climbing). He was found by a group of us (you know who you are!) a few weeks ago in the lower reaches of Manoa stream close to the Alawai.

Thanks to Inspire91 for use of the photos!!!!!!!!


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## Steven_Chong (Mar 17, 2005)

Another creature unfortunately suffering from Habitat invasion. From what I understand, they don't compete very well with the invasive crayfish. Just like bisculata's habitat has been taken over by neocaridina in many areas . . . after all, bisculata used to inhabit lower areas as well from what I understand.


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## fish newb (May 10, 2006)

Another beautiful shrimp!

How hard is it to breed those?

I say catch all those Crays that are invading and get rid of them !

-Andrew


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## Inspire91 (Jun 20, 2005)

WHAT A FIND!!!  hopefully we can someday pick up somemore, or run across one of those massive ones  if we do...ur grabbing it!


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## Veneer (Jun 12, 2005)

fish newb said:


> Another beautiful shrimp!
> 
> How hard is it to breed those?
> 
> ...


The larvae require saline water to mature.

The invasive crayfish at hand, _Procambarus clarkii_ (red swamp crayfish of Cajun cuisine and the aquarium trade), appears established beyond all possibility of extermination. Additional competitors include _Macrobrachium lar_ and _Macrobrachium rosenbergii_ (introduced to Hawaii for aquaculture purposes); a host of aquarium fish pose additional predation risks.

And that's not getting into other modes of habitat disturbance.


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## Steven_Chong (Mar 17, 2005)

Veneer said:


> The larvae require saline water to mature.
> 
> The invasive crayfish at hand, _Procambarus clarkii_ (red swamp crayfish of Cajun cuisine and the aquarium trade), appears established beyond all possibility of extermination. Additional competitors include _Macrobrachium lar_ and _Macrobrachium rosenbergii_ (introduced to Hawaii for aquaculture purposes); a host of aquarium fish pose additional predation risks.
> 
> And that's not getting into other modes of habitat disturbance.


Sounds dire. 

Those crayfish are definitely established beyond extermination. They're freaking everywhere.


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## RESGuy (Feb 11, 2007)

Very cool shrimp. It is too bad about habitat loss  Thanks for sharing


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## Kenshin (Feb 26, 2007)

That tells us as human beings, we should be very careful not to introduce exotic species into the wild and just keep them in captivity.


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## ManakooraMan (Nov 26, 2012)

Old thread, found it looking for info on m. grandimanus. 

as noted, we've had intentional releases of m. rosenbergii and m. lar into the local water bodies. the latter I believe took hold and inhabits the same areas as m. grandimanus.

Wonder if these could be hybrids? 

There have been macrobrachium cross-genus hybrids. The assymetry in the claws is fairly common among crustaceans (could be seen in some photos of m. lar for instance).

Macrobrachiums are fairly aggressive, so m. rosenbergii was chosen for both size and for being more docile.


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## Veneer (Jun 12, 2005)

I can pretty much assure you that _M. grandimanus_ is not hybridizing with _M. rosenbergii_ or _M. lar_. While there are always surprises in nature ... the successful crosses I'm aware of in this genus involved much more phylogenetically proximate pairings than would be the case here (and were often assisted by artificial insemination ... the size difference between _M. grandimanus_ and the other two alone would make natural mating extremely unlikely). What's more, _M. grandimanus_ and _M. lar_ seem to coexist stably -- without hybridization -- in many other localities of Near Oceania and Island SE Asia.

_M. lar_ doesn't have characteristically asymmetrical second chelipeds, by the way (though many other _Macrobrachium_ do). What you're seeing is partial regeneration of a lost limb.


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