Mystery Rises

Discussion in 'Stillwater' started by ak_powder_monkey, Apr 20, 2009.

  1. Ed Call

    Ed Call Mumbling Moderator Staff Member

    Barbless, thanks for crushing my hope and faith that I might induce a strike on a tiny midge in red. Maybe rather than attempt my favorite place with these things I'll go to my last skunking site and plan for another...and hopefully be rewarded with a surprise.
     
  2. Big E

    Big E Moderator Staff Member

    Instead of trying to tie a single daphnia on a very small hook, tie on a cluster of daphnia on a larger hook.

    Seen a neat fly that was just that was some type of synthetic fiber like angle hair with dabs of orange fabric glue on it. Suppose you could also use mono as well.
     
  3. cabezon

    cabezon Sculpin Enterprises

    The interest in Daphnia must be a spring thing. If you search the archives (yeah, that button along the top between New Posts and Quick Links), you end up with 35 threads on Daphnia, going back to June, 2002. Most are in March, April, May, or June. There is lots of interesting discussion there, both about Daphnia and their imitations and the strange behavior of trout that may indicate Daphnia feeding. There are jewels of wisdom in the archives.

    Steve
     
  4. Kent Lufkin

    Kent Lufkin Remember when you could remember everything?

    Dick, I beg to differ. See Paul (yellowlab's) fascinating video of daphnia he pumped from a rainbow's stomach just the other day at: http://www.feltseoul.com/ Scroll down until you see the YouTube video showing them in a pink-colored dish.

    K
     
  5. I stand corrected. That's a great video. The fish he sampled clearly are feeding on them. I would be curious what the density is like in the lake and if there is a threshold above which the trout are stimulated to feed on them.

    However, the high density at Pass may be unusual and may be either local within the lake or due to some aspect of the lake (springs or mild winter/spring conditions relative to lakes at higher elevation). For example, since Daphnia reproduce more rapidly at warmer temperatures, the mild temperature at Pass Lake may keep a higher base population than in some other lakes (eg, ones that freeze over), or in shallow water where it may warm up more during the day a localized high-density population may build up that is not representative of the entire lake. It seems that Daphnia population dynamics are more variable and site-specific than I realized.

    Here's some info from a source, funded by the NIH of all places, on Daphnia biology; probably more than most of you will want to know :) (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=daph&part=ch2):

    "The life cycle of Daphnia during the growth season is characterized by its asexual mode of reproduction (apomixis) (Figure 2.9). A female produces a clutch of parthenogenetic (amictic) eggs after every adult molt (if feeding conditions permit). ... The induction of sexuality seems to be triggered by a complex set of stimuli, the most important possibly being those that go hand-in-hand with a high Daphnia density, e.g., increased competition and reduced food availability. Abiotic factors alone, such as decreased day length and lowered temperature, also seem to play a minor role."

    "A well-known behavior of Daphnia is diel vertical migration, in which they migrate toward upper levels of the water body during nighttime and then back downward during the early morning and daytime. This behavior probably developed as a predator avoidance strategy. During daylight, the Daphnia hide from fish that hunt visually by moving to darker depths, whereas during nighttime, they take advantage of the richer food (planktonic algae) in the well-illuminated upper water levels."

    "Daphnia populations vary strongly in density throughout the growing season. They typically go through pronounced cycles, with densities varying by more than seven orders of magnitude within a single season."

    "In most habitats, Daphnia have low density or completely disappear during part of the year, usually the cold or the dry season. Recruitment in the following growing season is from resting eggs and/or from surviving females. There is rapid population increase in the early season (exponential growth), with doubling times of a few days (down to 3 days at temperatures of 20ÂșC and above). Growth is eventually slowed down by density-dependent competition, usually because of food shortage; however, predators may contribute as well. ... The peak in Daphnia density usually follows a peak in algae density and may be followed by the clear-water phase in which the Daphnia effectively remove most of the phytoplankton from the water. The resulting food shortage leads to a rapid decline in Daphnia density. In large eutrophic lakes in temperate regions, phytoplankton and Daphnia may go through two density cycles (a spring and a summer peak), whereas in nutrient-poor lakes, only one peak may occur in mid-season."

    What I would take away from this is that, while there may be some lakes that will have high densities of Daphnia at this time of year here in Washington, they would be the exception, rather than the rule, and that peak densities in most of our lakes will occur in mid to late summer. Most of our lakes are pretty 'nutrient-poor' compared to lakes in the midwest or east, although certainly some of our lowland and desert lakes are pretty nutrient rich.

    Dick
     
  6. Kent Lufkin

    Kent Lufkin Remember when you could remember everything?

    Thanks for the follow-up Dick. Besides Pass, one tree farm lake I know of also seems to have a large daphnia population. Since Pass and this lake are both spring-fed, I wonder if that results in more moderate water temperatures during winter and spring than lakes fed my creeks?

    K
     
  7. zen leecher aka bill w

    zen leecher aka bill w born to work, forced to fish

    I used to see a lot of red daphnia in stomach "samples" from Upper Hampton trout in early March.
     
  8. ak_powder_monkey

    ak_powder_monkey Proud to Be Alaskan

    looks like they were chasing smolt after all, I think I was seeing tail flip type rises and thinking they were hitting emergers, more likely smolt just below the surface. Most are very deep though. At any rate low and slow with a little streamer worked tonight

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