Resident coho feeding on 1/2" olive scud like "critter". What is it called?

Discussion in 'Saltwater' started by Roger Stephens, Apr 14, 2006.

  1. Roger Stephens

    Roger Stephens Active Member

    Yesterday i was checking a couple of estuaries for sea-run cutthroat and got lucky. One estuary had a nice mix of willing sea-run cutthroat and resident coho which appeared to feeding/chasing after chum fry. I kept one fat resident coho for dinner and it's stomach was filled with approximately 1/2" fat olive scud-like "critters" with just a few chum fry scattered in the "mix". I was surprised that there were not more chum fry in it's stomach. Does anyone know what those "critters" might be? Were they over-sized amphipods?

    As a side note, it appears that larger sea-run cutthroat have started to move away from many estuaries. About 1 1/2 weeks ago my fishing buddy and I have started to get some nice sized sea-run cutthroat up to 5-6 miles from the nearest estuary. So it is getting to be about time to start checking out spots where they hang out at mid-spring through summer.

  2. Dizane

    Dizane Coast to Coast

  3. Roger Stephens

    Roger Stephens Active Member


    Thanks for the help:thumb: ! The picture is a perfect match of the "critters" in the resident coho's stomach. There was not a name with the picture. Do you know what they are called?

    Next trip out I'll have to look on the underside of some sea weed and rocks to see what a live one looks like and how they act in water.

  4. cabezon

    cabezon Sculpin Enterprises

    Hi Roger,

    If you think that Dizane nailed it, then what they were eating were isopods. They are the same kind of crustacean as the pill bugs that you find in their garden. We have dozens of species in our area; some are found in the intertidal crawling around on rock surfaces at low tide while others are found under rocks during the day. Still other species (such as Idotea wosnesenskii - a mouthful) live on eel-grass blades; this species is a good bet for what you found in the belly of that silver.

    Isopods are similar to, but in a different taxonomic group from, amphipods. Amphipods are flattened side to side, while isopods are flattened dorso-ventrally. In both species (and in mysids too), the eggs are brooded under the thorax of the female and emerge as miniature adults - no free larval stage. A common vernacular name for amphipods in flyfishing is scuds (important as places like Rocky Ford, for example). There are some freshwater isopods (genus Asellus) too which are can contribute to the diets of trout.

  5. Dizane

    Dizane Coast to Coast


    That's a picture of an eelgrass isopod. I've collected a few and tossed them in the water to observe and they swim using their back segment as a flipper, much like a crayfish. They keep their bodies straight and fully extended when swimming, and quickly headed for the bottom or weed cover. I wonder if the silvers were picking off individuals which had been dislodged due to wave or tidal activity, or were actively rooting them out of the rocks and weeds. The fact that you found so many in one fish seems to suggest they were actively rooting them out, and not opportunisticly feeding on dislodged individuals.
  6. Roger Stephens

    Roger Stephens Active Member

    Dizane and Steve:

    Thanks for the great information:thumb: . It is nice to be able to understand a little bit more of the amazing food chain in Puget Sound available to sea-run cutthroat and coho salmon.