Non-native Atyids in the U.S.

Veneer · Post by **Veneer** » Mon Jun 05, 2006 2:11 pm

Gore, Robert H., George R. Kulczycki and Philip A. Hastings. 1978. A second occurrence of the Brazilian freshwater shrimp, Potimirim potimirim, along the central eastern Florida coast. Florida Scientist, 41(1): 57-62.

A 1997 Ecosummary report for the South Fork St. Lucie River, "the only remaining section of the historic St. Lucie River system that has escaped intensive development of the riparian zone and channelization of the stream bank" and "one of south Florida's few remaining meandering blackwater streams," attributes the presence of this species to "the unique tidal yet freshwater nature" of the body.

Does anyone know where breeding populations have been established? Under what circumstances was this species introduced? Could oceanic larvae conceivably have reached the mouth of the St. Lucie without human intervention?

Post by **Mustafa** » Mon Jun 05, 2006 6:39 pm

I really doubt that it's Potimirim potimirim. It would be highly unlikely for P. potimirim larvae to float from South America right through the caribbean, without establishing populations on any caribbean island, and then settle down in central Florida. I also don't see why anyone would introduce these shrimp. Introduction of such small prey species is highly unlikely unless thousands of them (tens of thousands) are released at once, as otherwise the odds of shrimp from a small population surviving and producing larvae (which also have to survive and return from the sea) is close to nil.

In this case I think the scientists made a mistake. Considering that their paper is from 1978 and that even current "shrimp" scientists have a hard time identifying shrimp under the microscope, I would not be surprised if this species is one of the Potimirim species that actually occurs in the caribbean instead of Potimirim potimirim. It would not be the first and last time that a species has been misidentified.

It might just be Potimirim americana, which found its way naturally to the Florida coast through floating larvae. Ordinarily the larvae can't get to the coast as the gulf stream moves away from the coast, but maybe some "freak" or random, highly unusual, currents carried thousands of larvae towards the coast at some point. Potimirim americana lives in Cuba, among other places, which is not that far from Florida. That sounds more likely then either south american larvae making it to Florida or someone shipping tens of thousands of shrimp from South America to Florida just to set them free and hope they establish themselves.

wklotz · Post by **wklotz** » Tue Jun 06, 2006 2:20 am

Hi Mustafa, hi all!

Mustafa wrote:I really doubt that it's Potimirim potimirim. It would be highly unlikely for P. potimirim larvae to float from South America right through the caribbean, without establishing populations on any caribbean island, and then settle down in central Florida.

I could not agree with your answer.
The paper given above is the second report f this shrimp in Florida. The first notification was given by Abele in 1971. He give some cirteria do differ between P. potimirim and other congeners an a drawing of the male pleopods. So there are not many doubs that this shrimp are really P.potimirim. There are some other reports of this species in the carribean sea. Fievet reported the species from Guadeloupe in 2001 and Lim 2002 from Martinique. I myself collected P. potimirim near the carribean coast of Panama this March. A picture from a female from Panama you can find in the Gallery of crusta10.de.

Greetings from Europe
Werner

Post by **Mustafa** » Tue Jun 06, 2006 7:42 am

Hi Werner!

Welcome to the forum!

Thanks for your input. So, you're providing more proof that P. potimirim does exist in the caribbean, albeit only in the southern caribbean and very close to South America (Paname, Martinique, Guadeloupe). As far as I know it has not been reported from further north, such as Cuba, Puerto Rico, Jamaica, Hipaniola etc.. The question still remains how P. potimirim would make it from the southern Caribbean all the way up to Central Florida. That's why I thought that some of the other Potimirim species are more likely to settle in Florida, since they occur much closer and the chance that *their* larvae make it to Florida is much, much higher. However, it is of course possible that P. potimirim did make it to central Florida against all odds and probabilities. Nothing is impossible I guess.

It could also be that P. potimirm has a much wider range in the Caribbean, but scientists have not discovered it in much of its range yet. To give you an example...I went to Curacao this year and collected some Macrobrachium from a cave. In a relatively recent paper that describes the shrimp species in Curacao, only two species are reported from that cave, one cave-dwelling Atyid shrimp (which I could not find) and one Macrobrachium species (which I did find). However, I caught a third species of Macrobrachium, which can only be Macrobrachium carcinus or an undescribed close relative/subspecies. I am going to contact the scientist who wrote that paper to notify him about this find.

In any case, this just shows that the "shrimp world" still has not been thoroughly researched and surprises wait around the corner. I would not be surprised if species such as Xiphocaris, Jonga and various Macrobrachium sp. not reported from Florida do end up being discovered in Florida in the future.

Veneer · Post by **Veneer** » Sun Jul 30, 2006 4:42 pm

Mustafa wrote:I would not be surprised if species such as Xiphocaris, Jonga and various Macrobrachium sp. not reported from Florida do end up being discovered in Florida in the future.

Interestingly, I've found a paper noting presence of M. heterochirus in Florida as well.

This document makes the following statement on Potimirim potimirim, which would seem to point towards intentional introduction: "Comments: In fresh water. Succesfully introduced in Florida (Gore, Kulczycki & Hastings 1978)."

On Atya scabra: "Comments: In fresh water. Introduced in western United States (Abele & Kim, 1989)."

Has anyone heard more on the latter introduction?

Post by **Mustafa** » Sun Jul 30, 2006 5:10 pm

Veneer wrote: "Comments: In fresh water. Succesfully introduced in Florida (Gore, Kulczycki & Hastings 1978)."

On Atya scabra: "Comments: In fresh water. Introduced in western United States (Abele & Kim, 1989)."

Has anyone heard more on the latter introduction?

I have seen that website before. That's the only website that refers to these two species as being "introduced" to the US. I wonder if the author of the website had trouble expressing him/herself in english and hence used the word "introduced" incorrectly. I don't see any logical or economic reason that would justify introducing a dwarf shrimp and a filter shrimp to the US. I remember searching various databases for information about introductions of above mentioned species and could find nothing. The title of Gore, Kulczycki & Hastings paper does not imply any introduction whatsoever.