Hey, everyone.

I'm an undergraduate student who's been conducting research on genetic relationships in a group of freshwater prawns (Macrobrachium). This group is mostly tropical, but Texas is fortunate enough to have at least four native species.

I'm in Boston right now, but I'll be heading down to Texas in mid-May/early June to investigate two really interesting sites: (1) Lake Corpus Christi and (2) Buffalo Bayou, hopefully collecting some tissue samples for DNA analysis.

If you've ever run into freshwater prawns -- either here or anywhere else in Texas, it'd be great to hear from you.

(1) The fact that prawns are occurring upstream of the dam at Lake Corpus Christi is pretty surprising, since their young are believed to require brackish water for development. In other words, large dams are expected to dramatically interrupt their life cycles and rule out the existence of populations in artificial impoundments. But in Corpus Christi, apparently, anglers are continuing to catch these critters -- something strange is going on.

(2) Based on photos I've seen of the Buffalo Bayou prawns, it's clear that at least some of them belong to an undocumented non-indigenous species -- Malaysian prawns (Macrobrachium rosenbergii) which presumably escaped from aquaculture. This would be the first record of feral populations in Texas.

Both of these have important fisheries management implications, so I'd appreciate any reports or tips.

I am interested in the fresh water prawns on Lake Corpus Christi.
I grew up in the area and recall catching small, somewhat translucent, shrimp we referred to as "grass shrimp".
They were about 1" long and we teased our crappie minnows with this shrimp.
Is this similar to the species you are studying?

Thanks for the reply. From your description, these sound like they belong to the genus Palaemonetes (you'll often see them sold as bait or feeders for aquarium fish under the heading of "grass" or "ghost" shrimp). The prawns I'm interested in are indeed closely related (they belong to the same family) and their young are hard to distinguish from grass shrimp, but the adults tend to get much larger (3 inches to over a foot, depending on the species). The larger prawns have robust pincers and resemble crayfish or even lobsters, but some smaller species really do look just like magnified grass shrimp.

Hello,
I'm new to the forum, but I do know that the San Marcos River in San Marcos has a population of very large shrimp/prawns. I'm guessing they are the type you are seeking.

Also the Guadelupe River in the same area has a population of them.

??? foot long prawns ???

In college we used to go snorkel the river at night with dive lights. You could go deep in some of those river bends (+- 15ft), and at the bottom there would be little overhanging shelves - poke your head up there with a light and there would be a whole line of these not-so-little prawns sitting there staring back at you.

In reference to the dams...it always used to amaze me how many dams these little dudes had to go around to get up to San Marcos. Tenacious creatures for sure.

LIKE THIS???

Long ago....

Late seventies when I was at A&M, we did some seining on sand bars in the Brazos River around a place called "Batt's Ferry." We caught some huge prawns, well over a pound on one of those sand bars.

Still a long time ago, but in the early nineties, I did some work where we did a polyculture project with Machrobrachium rosenbergiiand koi in the same pond. The koi did poorly, the prawns must have eaten them all, but the prawns did real well, growing to about three ounces each. We had one very good party off them, and that was the last of my prawn experiments.

Back around 2003 or '04 we did a lot of fish collecting in the Houston Ship Channel, Greens Bayou and Carpenter Bayou, but I do not remember catching any prawns in any of our traps, nets, seines, etc. We did catch a lot of tilapia, plecostomus and grass carp (all non-native species) though.

Holy Big Shrimp Batman!!!!

Also, that man must have the stongest forearm muscles on the planet, he doesn't even look like he is straining

I am currently raising a Macrobrachium rosenbergii. Raised from 1 inch to 10 inches (body only) in pure freshwater. It took 1 year for it to grow this size.

Juvey


Now




Videos
http://www.youtube.com/watch?v=oxWY3f68Ig4
http://www.youtube.com/watch?v=KaGEhR0hdps

Thanks for the additional information, everyone.


I've actually been down to San Marcos twice before and seen some of the work being done at Texas State with the M. carcinus there. Their migratory instinct is astounding for sure, but I'm still having a hard time seeing how they'd make it past Wesley Seale Dam to enter Lake Corpus Christi.

For anyone else reading this, I'd be especially interested to hear if you've seen these prawns in artificial lakes or reservoirs.


No joke:



... and they get even bigger. As Waldo Schmitt wrote in 1965:


The Devil's River population is, unfortunately, now extinct -- most sources attribute this to the construction of the Falcon and Amistad Dams.


Thanks for the photos. Here are some of a young M. carcinus I kept a few years back:

1+ San Marcos River, use to catch them with a dip net while trying to catch mosquito fish. I have never caught one that was over 2" though

It look like river fresh water shrimp in VietNam but average only 5 to 6inch long