Shrimps/prawns in Freshwater

Ukwildlifeo · #1 (**permalink**) 17-11-2010, 08:07 PM

I had a dip with a net in a ditch today checking to see what in there and I caught plenty of mayfly nymphs (pond olive I believe), caddisfly larvae and diving beetle larvae which all suggest the water is fresh or near enough. But I also caught 2 shrimp/prawns. Anyone else come across them in freshwater before?

Lindsay-c · #2 (**permalink**) 17-11-2010, 08:56 PM

Yeah, many times when I've been lifting over rocks in freshwater streams I've come across freshwater shrimp among mayfly and stonefly. Look up Freshwater shrimps:

FSC (Field Studies Council) - Life in Freshwater

Freshwater Shrimp (Scuds, Sideswimmers) - Class: Crustacea, Order: Amphipoda

They what you mean?

Ukwildlifeo · #3 (**permalink**) 17-11-2010, 09:39 PM

Sorry Lindsay I should have been more clear - Im refering to the decapod true shrimps/prawns (like those usually found in rockpools) not the amphipod freshwater 'shrimps' Gammarus sp.

Ukwildlifeo · #4 (**permalink**) 17-11-2010, 09:56 PM

Heres a pic of the crustacean in question

Fauna · #5 (**permalink**) 17-11-2010, 10:04 PM

This looks like a Palaemonetes sp sold for fresh water aquarians?

Looks like somone has emptied their contents of their aquarium into this water.
They can live in ponds out doors but i believe they get killed off when the water gets to cold (thats if it is what i think it is)?

Ukwildlifeo · #6 (**permalink**) 17-11-2010, 10:55 PM

Quote:

Originally Posted by Fauna

This looks like a Palaemonetes sp sold for fresh water aquarians?

Looks like somone has emptied their contents of their aquarium into this water.
They can live in ponds out doors but i believe they get killed off when the water gets to cold (thats if it is what i think it is)?

The ditch is a bit out the way for someone to dump stuff (well more a case they will pass a few ponds before reaching the ditch) but near an estuary (within 100m) and gulls and ducks move between the two - Im wondering if they came across on the feet of one of these perhaps as larvae?

There is a species of prawn found in freshwater of the Tamar and the Broads according to an old book of mine.

triops · #7 (**permalink**) 17-11-2010, 10:56 PM

I was amazed some years ago searching at a pond near Romney Marsh, to catch dozens if not hundreds of shrimps like these. I was so surprised that I had to taste the water and found that as far as my taste buds could tell there was no salt in it. So, marine shrimps of some species can survive in (almost) fresh water.

nightshade · #8 (**permalink**) 18-11-2010, 02:35 AM

Could it be a Fairy Shrimp? I seem to remember that there are pockets of these unusual shrip the eggs can be viable after 15 years and they appear in puddles on Salisbury Plain

Dogghound · #9 (**permalink**) 18-11-2010, 08:14 AM

Two possibilities spring to mind, Palaemonetes varians and Palaemon longirostris. Is this ditch network linked to a river?

Ukwildlifeo · #10 (**permalink**) 18-11-2010, 08:38 AM

Quote:

Originally Posted by triops

I was amazed some years ago searching at a pond near Romney Marsh, to catch dozens if not hundreds of shrimps like these. I was so surprised that I had to taste the water and found that as far as my taste buds could tell there was no salt in it. So, marine shrimps of some species can survive in (almost) fresh water.

Thnaks, looks like this isnt unique. I wonder how they get there.