Jassa pelagica

Erling Svensen Here is a picture like they normally live together in colonies.

Erling Svensen I do not think they are juveniles. They sit in colonies, but I can be wrong.

Rob Spray Ours look more like this: http://www.1townhouses.co.uk/pelagicpixels/2009/EastJuly09/Sunday%20afternoon%20Vera/slides/P7052393.htm

Rob Spray Maybe this will embed better: http://www.1townhouses.co.uk/pelagicpixels/2009/EastJuly09/Sunday%20afternoon%20Vera/slides/P7052393.jpg

David Kipling There's also Parajassa pelagica, another tube-building critter, although I think the wavy arms at the front are different: http://species-identification.org/species.php?species_group=crustacea&id=369

David Kipling Yeah, there's loads round the corner to the right at Martin's haven, I've got pics somewhere. Sarah'll remember the name.

David Kipling (you should have swum further!)

Marco Faasse It is true that these look a bit different from Jassa Erling Svensen. Their second antennae are not that robust and they are held straight (usually downcurved in Jassa). Furthermore their backs seem banded, while the pattern on Jassa is more irregular. As Dawn Watson says in Jassa sizes tend to be segregated, but often you see a few larger ones between the small. It is also true that the juveniles look different from adults, with less robust and less densely haired second antennae. ID of juveniles is difficult and ID of adults not showing their legs as well. It's almost impossible to give a name to specimens in their tube as in your photo, Erling. There are three or more Jassa species in the NE Atlantic, there's Parajassa as David Kipling says, there's Microjassa, there's Ischyrocerus and there's still more ... For a certain ID it's necessary to collect or to take a good picture of an animal ouside of its tube. I would be glad to collect and ID some.

George Brown Photis longicaula. The more I look the more I find.

Erling Svensen Sorry George, but my brain do not understand Photis longicaula. Is this a name on an amphipode???

David Kipling Photis longicaudata: http://data.nbn.org.uk/gridMap/gridMap.jsp?allDs=1&srchSpKey=NBNSYS0000177164

David Kipling I think longicaudata translates as long tail?

Marco Faasse Photis longicaudata is another tube-building amphipod that filters the seawater with its antennae. It builds its tubes in tight colonies around the tip of Cerianthus tubes ... I think there's a pdf of a scientific article about its habits on the web. Its hindmost uropod or "tailleg" is longer than in its closest relative -> longicaudata David Kipling :-)

Marco Faasse Can't find a pdf; only have a photocopy ...

David Kipling I'm surprised the waters round Pembrokeshire aren't crystal-clear with all these ascidians, sponges, anemones, bivalves, hydroids, bryozoans and amphipods filtering everything from the water column! I wonder which make the greatest different to water quality (as in sediment/phytoplankton load)?

Marco Faasse Maybe you should turn it the other way around: that all those filter feeders abound especially there where there is so much to filter that they can't cope with it.

Marco Faasse Now I see that Dawn Watson already mentioned a remark of George Brown about the habits of Photis longicaudata ...

David Kipling Absolutely! The same was true for Raja Ampat, where many places were actually quite low-viz because of the plankton/sediment load but I have never seen so many ascidians in one place...

Marco Faasse But you are right David Kipling that those masses of filter feeders do have an influence on suspended matter. In the relatively small water mass of the Oosterschelde we see that viz improves very quickly when influx of suspended matter stops for a while. Then the mussels and ascidians do their job.

David Kipling Lisa Draughon did a thesis on using Styela plicata for bioremediation of sediment-rich waters (basically floating balls pre-covered with ascidians thrown into the water ... clears them up a treat since each animal filters > 3l/hr of water).

Marco Faasse And zebra mussels have been used in fresh water to improve viz.

Paula Lightfoot David yes there were lots of tubes, here's a better photo. Not sure what to record it as though, I know Jassa falcata makes tubes like this but perhaps other amphipods do too?

David Kipling We should find out - I bet there's someone on here who would know. Post the question over on SSID and see what people think.

David Kipling Although if it's the only one you know Dawn, perhaps you're putting loads of different species down as Jassa ;)

David Kipling A little googling comes up with another critter that seems to build tubes from my limited reading - Parajassa pelagica. Out-competes Jassa in shallower conditions with wave action apparently, and is another biofouler. Can't find any pictures of it. Keith Hiscock has written about it.

David Kipling It's mentioned in this wind farm biofouling report (which is an interesting read anyway, especially given the plan to put a farm just north of Lundy). http://www.agentschapnl.nl/sites/default/files/bijlagen/Pre-survey%20of%20marine%20fouling%20on%20turbine%20support%20structures%20of%20OWEZ%202006.pdf

David Kipling Can't find any pictures of it in tubes - have posted on the SS ID group where Keith is a member, he'll know.

David Kipling Are there any tube-dwelling amphipods in the UK other than Jassa falcata? I've come across mention of Parajassa pelagica, in the context of being a shallow-water biofouler, but can't find any pictures of it in its nests/tubes. And I have no idea if there are additional species. Keith ... you've written about these species, can you comment?

Jon Moore There are lots of tube dwelling amphipod species in the UK, but most of them live in sediments, e.g. all the Ampeliscids. Epifaunal tube dwellers include Lembos websteri, Erichthonius brasiliensis, Ampithoe spp, Microdeutopus spp, some of the Corophium spp and numerous others. However, most of the ones I see diving normally turn out to be Jassa falcata - they do seem to like the same tide-swept habitats that divers like.

David Kipling Thanks Jon!

Keith Hiscock Parjassa pelagica occurs in shallow depths on wave lashed reefs. Deeper than P. pelagica, Jassa falcata is the dominant jassid forming muddy tubes that may be so extensive that the seabed looks like a farmyard. Bob Forster commented in his 'Underwater observations on the fauna of shallow rocky areas ....' (JMBA 37, 473-482) that P. pelagica occurred to 13m at the Eddystone but only 2-4m inshore at the Mewstone. I have not found the definitive paper about depth ranges and do not have an image of Parajassa.

David Kipling Are there any tube-dwelling amphipods in the UK other than Jassa falcata? I've come across mention of Parajassa pelagica, in the context of being a shallow-water biofouler, but can't find any pictures of it in its nests/tubes. And I have no idea if there are additional species. Keith ... you've written about these species, can you comment?

Jon Moore There are lots of tube dwelling amphipod species in the UK, but most of them live in sediments, e.g. all the Ampeliscids. Epifaunal tube dwellers include Lembos websteri, Erichthonius brasiliensis, Ampithoe spp, Microdeutopus spp, some of the Corophium spp and numerous others. However, most of the ones I see diving normally turn out to be Jassa falcata - they do seem to like the same tide-swept habitats that divers like.

David Kipling Thanks Jon!

Keith Hiscock Parjassa pelagica occurs in shallow depths on wave lashed reefs. Deeper than P. pelagica, Jassa falcata is the dominant jassid forming muddy tubes that may be so extensive that the seabed looks like a farmyard. Bob Forster commented in his 'Underwater observations on the fauna of shallow rocky areas ....' (JMBA 37, 473-482) that P. pelagica occurred to 13m at the Eddystone but only 2-4m inshore at the Mewstone. I have not found the definitive paper about depth ranges and do not have an image of Parajassa.