What do the coho near olympia eat?

[dmoocher]

I think I found the answer...I've been doing really well on sparse baitfish patterns but today I though I'd try an orange spider and came up with this guy...15 inches and stuffed. Any good sandshrimp patterns out there? I've been fishing this beach most Sundays since mid January, haven't been blanked yet...and now...I just jinxed myself.

btw: Half the sandshrimp were still kicking when I opened him up...must have been a pretty good "hatch".

[nativewiggler]

WOW!!!!

I enlarged the pic and got a really great view too!!!

You know that belly was beyond full!!! Your lucky he bit with being such a greedy little booger...:p

Thanks for sharing, great pic!

Not sure about the sandshrimp pattern though... Anyone else know???

[Dizane]

dmoocher,

Here ya go on that sand shrimp pattern:

http://www.washingtonflyfishing.com/board/showthread.php?t=37384&highlight=sand+shrimp

Check the last post in the thread.

[Roger Stephens]

dmoocher:

IMHO those small shrimp in your picture look like coon stripe shrimp(reddish brown color)rather than sand shrimp(tan color).

Roger

[cabezon]

I don't think that they are sand shrimp (Crangon sp. - wrong color, should be tan to gray as Roger pointed out), but I don't think that they are coon-striped shrimp (Pandalus danae - should have a well-developed tail and thorax) either. Plus, I've seen my share of dead Crangon and Pandalus in the stomach contents of sculpins and they have never been such a vivid red color. Instead, I think that they are mud shrimp (Callianassa or Ubogebia). Why? First, it seems from the photo that some of them have one very large claw, a characteristic of this group (and lacking in either Crangon or Pandalus). Second, neither the tails nor the thorax is very well-developed, again consistent with a burrower like Callianassa or Ubogebia.

If they are mud shrimp, the question that comes up is how did the salmon access them. These shrimp are supposed to be burrowers in soft sediments. Why would they be out in the open where hungry trout, salmon, flounder, or staghorn sculpins could eat them? Might your salmon have taken advantage of the moon last night to eat the shrimp when they were out foraging on the surface?

That's my $0.02

Steve

[dmoocher]

Might your salmon have taken advantage of the moon last night to eat the shrimp when they were out foraging on the surface?

Not a chance...these had been swallowed up during the tide this morning, they were still alive...they are the burrowing mud shrimp (males with one larger claw)...the same genera you get in the styrofoam container at the bait shop. There must have been an emergence...I doubt he was rooting in the mud for them....but it does make you wonder????

[cabezon]

The problem is that these kind of shrimp aren't known for any type of "emergence", at least during the day, plus those individuals looked too small to be mature, and they can't swim worth spit. If they were eaten in daylight, they were definitely out in the open in the wrong place at the wrong time OR silver salmon have some clever techniques to root them out of their burrows that I have never heard of.

I might make a speculative defense on my hypothesis that they were caught during the night / early morning. Death is not necessarily immediate for food items in the stomach [I did some experiments many years ago that showed that snails with an operculum can pass through the whole digestive tract alive and amphipods in some other feeding experiments were regurgitated alive after almost an hour in the stomach of tidepool sculpins]. First, given the volume of food in that silver's stomach, it is unlikely that the pH was very acidic yet. It takes quite a while to change the acidity of such a large volume of food. Second, these shrimp are very adapted to anaerobic environments. The minimal oxygen in the stomach may not have been as quick a death sentence as it would be for other crustaceans.

Thank you very much for sharing,

Steve

[Roger Stephens]

Steve:

Your insights and knowledge of organisms in the diet of fish in Puget Sound is much appreciated. It helps in our quest to be successful fly fishers on the waters of Puget Sound.

Roger

[Freedon]

Great photo, I want to add my thanks. How did the fish take your fly? I'm guessing that you were over a sandy bottom, but were you drifting your Spider in the surface film, or dredging the bottom with a sinking line? That information might help Steve and Roger figure out how the shrimp got out of the sand and into the fish!

[dmoocher]

Roger/Steve/Don....

These were fresh mud/sand shrimp...no digestion or acidity was apparent in the gut, many were still alive...don't kow the max survival time in the gut so I can only guess. Don, Tom B. knows exactly where I was...standing in the mud flats between the patches of sand dollars doing a slow, jerky retrieve on my clear intermediate.

Steve, it is possible that they were taken at first light during the high slack ~ 4-5 hrs before I cleaned him. All were about an inch to inch and a half.

[CovingtonFly]

Did you eat the shrimp too? That might have made a nice Gumbo.

[Freedon]

Did you eat the shrimp too? That might have made a nice Gumbo.

Gawd! I shot an18lb cabezon under Fox Island Bridge one Halloween, and in it was a "fresh" legal sized dungeness crab, swallowed whole. For about a minute, I sniffed the crab, turned it this way and that, considering, 'hell, how bad it could have gone?" Then I saw a seagull eying me and regained enough pride to do the right thing. It was comforting to know that I can draw the line somewhere.

[Catfish Jack]

Toss it in the pot with the shrimp! LOL!

IMHO, moocher makes sense with the shrimp still kicking and that many in this coho's guts.

I am no expert by far, but it just seems like common sense to me.

Go easy on me boys, I am not sure who out pisses who here yet!

[Jon Borcherding]

Hypothesis:
1. Intensive harvest of geoducks with high pressure water jets blast shrimp out of bottom substrate.

2. Harvesting, (poaching) occurs at night so as to avoid attention of public.

3. Cutthroat, being the opportunistic critters that they are, are quickly conditioned to key in on geoduck harvest as a food source.

OK, it's a hairbrained idea but it's not impossible is it? :confused:

Was there any other activity that could account for the mud shrimp being dislodged from the bottom?
Night time clam digging, dredging, bulkhead building, anything like that?

Dang! I love a good mystery!

JonB