Freshwater mussels lure fish

[Mark Melton]

The strange, savage life of a freshwater mussel

Oh, you think mussels are basically rocks? I’m afraid you are very wrong.

www.vox.com

 

[Billy]

Fascinating

 

[Draketake]

Thank you for sharing. Had no idea.

Have a good weekend.

Bob

 

[Jim F.]

Wow! I'll never view them the same. What fascinating critters.

 

[SilverFly]

Amazing. That explains the things I've seen attached to steelhead gills in the fall.

 

[Matt B]

I find these critters fascinating, too. Globally, North America is a hotbed for freshwater mussel species richness but here in the Western US we missed out on that with only the pearlshell, western ridged and floaters, the latter of which the taxonomists are having fun with debating splitting and lumping.
@SilverFly we don’t know a ton about what triggers the populations of mussels to sync up their reproduction, but I’m not sure if the timing explains what you’re seeing on (adult?) steelhead in the fall. Get a microscope next time to check it out! The glochidia just look like teensy tiny mussels. http://xerces.org/sites/default/files/publications/10-030.pdf

 

[Mark Melton]

I find these critters fascinating, too. Globally, North America is a hotbed for freshwater mussel species richness but here in the Western US we missed out on that with only the pearlshell, western ridged and floaters, the latter of which the taxonomists are having fun with debating splitting and lumping.
@SilverFly we don’t know a ton about what triggers the populations of mussels to sync up their reproduction, but I’m not sure if the timing explains what you’re seeing on (adult?) steelhead in the fall. Get a microscope next time to check it out! The glochidia just look like teensy tiny mussels. http://xerces.org/sites/default/files/publications/10-030.pdf

Thanks for including the pdf. It contained a lot of information not included in the article I cited. Living approximately100 years surprised me.

 

[Matt B]

Thanks for including the pdf. It contained a lot of information not included in the article I cited. Living approximately100 years surprised me.

Yeah with the long lived Margs there can actually be populations of only old individuals that have not successfully reproduced for whatever reasons for years or decades. Folks have used freshly collected specimens, specimens from historic archives, and from prehistoric middens as environmental tracers of changes to river systems over time!

 

[SilverFly]

I find these critters fascinating, too. Globally, North America is a hotbed for freshwater mussel species richness but here in the Western US we missed out on that with only the pearlshell, western ridged and floaters, the latter of which the taxonomists are having fun with debating splitting and lumping.
@SilverFly we don’t know a ton about what triggers the populations of mussels to sync up their reproduction, but I’m not sure if the timing explains what you’re seeing on (adult?) steelhead in the fall. Get a microscope next time to check it out! The glochidia just look like teensy tiny mussels. http://xerces.org/sites/default/files/publications/10-030.pdf

Not sure what species we have in SWW rivers but they have a somewhat elongated, and thin shell. More like a small, oval razor than a butter clam.

Haven't been to a couple spots on the Washougal in many years where there were (are?) large mussel beds a few square yards in area. I've never seen any weird "lures" in those beds, but would be interesting to know if those steelhead were duped into becoming hosts. The larvae I remember seeing attached to steelhead gills were fairly large at about 1/4" long.

 

[Peyton00]

The skookumchuk has freshwater mussels....or at least they look like mussels.

 

[Mark Melton]

Not sure what species we have in SWW rivers but they have a somewhat elongated, and thin shell. More like a small, oval razor than a butter clam.

Haven't been to a couple spots on the Washougal in many years where there were (are?) large mussel beds a few square yards in area. I've never seen any weird "lures" in those beds, but would be interesting to know if those steelhead were duped into becoming hosts. The larvae I remember seeing attached to steelhead gills were fairly large at about 1/4" long.

Used to live near the Washougal (Camas) about 40 years ago. I can remember seeing fair numbers of mussels there. No idea if they are still there or not, nor what species they were.

 

[Matt B]

Not sure what species we have in SWW rivers but they have a somewhat elongated, and thin shell. More like a small, oval razor than a butter clam.

Haven't been to a couple spots on the Washougal in many years where there were (are?) large mussel beds a few square yards in area. I've never seen any weird "lures" in those beds, but would be interesting to know if those steelhead were duped into becoming hosts. The larvae I remember seeing attached to steelhead gills were fairly large at about 1/4" long.

The pearlshell seem to be most common in the higher energy more gravelly cobbley rivers we frequently like to fly fish. Western Ridged mussels seem to occupy similar habitat but are generally rarer and more commonly found to the east of SW WA. Floaters generally occupy slower habitats with finer sediments, but beds have been found with all three species, and I recently read a report on the Willamette where a predominately pearlshell bed was investigated and they identified a single western ridged out of hundreds of pearlshells.
Here is a nice little ID guide for us PNWers.

https://pnwmussels.org/wp-content/uploads/2016/07/QuickMusselGuide_CTUIR.pdf

 

[SilverFly]

The pearlshell seem to be most common in the higher energy more gravelly cobbley rivers we frequently like to fly fish. Western Ridged mussels seem to occupy similar habitat but are generally rarer and more commonly found to the east of SW WA. Floaters generally occupy slower habitats with finer sediments, but beds have been found with all three species, and I recently read a report on the Willamette where a predominately pearlshell bed was investigated and they identified a single western ridged out of hundreds of pearlshells.
Here is a nice little ID guide for us PNWers.

https://pnwmussels.org/wp-content/uploads/2016/07/QuickMusselGuide_CTUIR.pdf

Thanks for posting this. The Floater shell at the upper right are the type I'm most familiar with, which is odd because because these were well upriver in a fairly high gradient section. Although the beds were in a slow, shallow area of mixed/firmly packed cobble downstream of a deep pool. Even so, I'm sure I've seen pearl shells somewhere based on the "bent" shape of the shell.


Edit: Missed that floater larvae attach to fins, vs pearlshell on gills. So pearlshells must be present in the Washougal also.

 

[Smalma]

Silverfly -
Things you see in the steelhead gills is likely Salmincola californiensis; a parasitic copepod. After a short free swimming stage after hatching the larvae attach to the gills (and other locations) of various salmon and trout where they eventually mature and release eggs to repeat the cycle.

Curt