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“Blinded Me with Science”–February 24, 2014

Cue the theme music, “Blinded Me with Science” by Thomas Dolby:

The March 2014 issue of NEBRASKAland magazine just went on-line, Digital NEBRASKAland; there is a short piece there that Nebraska anglers will find of interest.  I have blogged before about how unique Nebraska’s sandhill lakes are, and in recent years fisheries research has taught us a lot more about those waters (e.g. “Blinded Me with Science”–February 25, 2013, “Blinded Me with Science”–November 21, 2011 ).  In March 2014′s issue of NEBRASKAland, Mark Kaemingk and Dr. Dave Willis report on some more of that research where they specifically looked at the timing of yellow perch and bluegill hatching and competition between those two species in a Nebraska sandhill lake.  You can see that story on page 6 of the March issue, “Competition Between Two Favorite Nebraska Panfish?”  It will not take you long to read it and even though it is fisheries science, you will be able to understand and learn something from it.

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“Don’t need no stinkin’ perch.”

We know that Nebraska’s sandhill lakes are incredibly productive and are capable of supporting very healthy, abundant, and fast-growing populations of several panfish species all in the same lake.  However, just because those systems are incredibly productive and can produce enough food to feed several species of panfish, that does not mean there are not interactions between panfish species.  Mark and Dave’s report indicates that the timing of yellow perch and bluegill hatching can give a competitive advantage to the earlier-hatching yellow perch early in their lives.  However, that does not mean that yellow perch are going to always have the upper hand over bluegills in sandhill lakes; some years late cold spells will “whack” the early-hatching yellow perch and then the competitive advantage swings to the later-hatching bluegills.

As I am always pointing out, fisheries are dynamic and there are a lot of variables beyond our control.  Large year-classes of yellow perch may be produced in some years under certain conditions while other years there will be large year-classes of bluegills and in yet other years there may be relatively small year-classes of both species produced.  No, there may not be much that fisheries managers can do to control the variability in year-class production, but understanding those mechanisms and interactions does help us realize there are always going to be “ups” and “downs”, good years and bad years.

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“Don’t need no stinkin’ bluegill.”

Let me add a couple of personal notes:  Mark Kaemingk now is doing some post-doctoral fisheries research work in New Zealand!  Unfortunately, we just lost Dr. Willis a few weeks ago, Dr. Willis.

The next time you stare down a sandhill lake ice hole hoping for a big perch or a big bluegill to bite, ponder the world below the surface of the water and how intricate it is!  If you think about that for a moment, you will have a great appreciation for that big perch or big bluegill when you do catch it!

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About Daryl Bauer

Daryl is a lifelong resident of Nebraska (except for a couple of years spent going to graduate school in South Dakota). He has been employed as a fisheries biologist for the Nebraska Game and Parks Commission for 25 years, and his current tour of duty is as the fisheries outreach program manager. Daryl loves to share his educational knowledge and is an avid multi-species angler. He holds more than 120 Nebraska Master Angler Awards for 14 different species and holds more than 30 In-Fisherman Master Angler Awards for eight different species. He loves to talk fishing and answer questions about fishing in Nebraska, be sure to check out his blog at outdoornebraska.org.

8 comments

  1. Daryl,

    I am gathering that a lake that is void of aquatic vegetation probably has trouble sustaining a good population of zooplankton. The lake with an abundance of aquatic vegetation tends to succeed more, correct?

    Let’s say in a perfect world, we have this lake that is void of submergent vegetation( I think that’s a pointy-headed terminology for sea weed)and has an occasional turbid period after heavy rains. It also has a population of rough fish present but not overwhelming. Does this lake have an ability to sustain any zooplankton population ?, if so, what are the contributing factors?

    Thanks! , I’ve got more!

    • Ray,

      All waters have zooplankton. The types and sizes of zooplankton will vary, and yes, water quality and other habitat conditions have an impact. Clear waters without any planktivorous fish tend to have the most and largest zooplankton. More turbid waters will still have zooplankton but certainly less and yes, likely smaller types.

      Daryl B.

      • Daryl,

        I was sniffing around that pond boss site and viewed a video from the “Bugman”. That was an interesting look into something I had no clue about. That company figures out how to remove nuisance vegetation sometimes with no chemicals. They use a lab to break down a plant and find it’s weakness, then these mad scientists whip up some magic to degrade and eliminate the problem. I guess that’s what you mean by “Blinding me with Science!”, you weren’t kidding! It was humbling and you guys don’t wear little caps with spinning propellers like I was led to believe, maybe a spinning muskrat hat though?

        Last question, I promise. Has anyone ever tried to create a “Bloom” of zooplankton prior to stocking a lake or impoundment with fry? Basically what I’m asking is ,can you “fertilize” zooplankton and help an ecosystem or is that just nuts?

        Thanks !

        • Ray,

          Sorry to disappoint you; I have not been working on any top secret vegetation control measures. I have done some pretty “far out” stuff in the past though.

          Your question on the zooplankton blooms is an excellent one and in fact yes, we do try to “fertilize” zooplankton. In our fish hatcheries, we often try to encourage the growth of terrestrial vegetation on pond bottoms before the ponds are flooded and fish are added. In fact we might even plant millet or some other type of grass to get it to grow on those pond bottoms. And, we often incorporate fertilizers into dry pond bottoms before those ponds are filled with water. Those activities are done exactly to provide a pulse of productivity when a pond is flooded which will result in a nice bloom, “crop”, of zooplankton just when fry are added to the pond.

          Obviously the logistics of doing that kind of thing in the wild are usually impractical, but there definitely are zooplankton blooms that occur in nature too. As the water warms each spring the aquatic food chain begins to ramp up and that results in natural zooplankton blooms throughout the spring. Young of many fish species take advantage of those blooms and that may be one reason many of our fish spawn sometime in the spring and early summer. Another example would be anytime water floods terrestrial habitats a great pulse of productivity is released resulting in zooplankton blooms which again are very beneficial for fish. That is one reason why high water events are important parts of river ecosystems and also is a huge reason why new reservoirs are so productive, why fish grow so well in new reservoir environments.

          Daryl B.

          • Thanks for the comments Daryl, that answered my questions. The correlation of spring spawning of fish in inland waters and “blooms” of zooplankton makes complete sense due to a usual high water event in spring, given we have a wet spring.

            That made me think how important it is that salmon die after the spawn in the fall in rivers, they compensate for the lack of nutrients in the river for fry by fertilizing a river with their own bodies.

            You broke that down for a novice, that’s why I keep reading this blog. Thanks

          • Ray, yes, that is exactly what Pacific salmon do! Those runs of salmon are very important for the entire ecosystem in those areas.

            Daryl B.

  2. Daryl,

    Well Mr. Bauer, I have a rounder-head vs a pointy-head so I’ll ask a few questions.

    Is the Sandhill region the only testing ground used for Daphnia in our state? I am guessing it is probably a one of a kind region of lakes , therefore, a good testing ground. Is it based on there isn’t as much agricultural run-off in these lakes? You brought up science and I am curious.

    The impoundments we have scattered across the eastern part of our state I realize, are different water qualities. If I’m not mistaken, I can see Daphnia with the naked eye correct? With the aid of a floating light I witnessed what appeared to be Daphnia attracted to a light source in an area lake. This particular lake has residential run-off from lawns. Do fertilizers have a direct effect on algae blooms in lakes with residential run-off, I guess what are herbicides doing to counter act that?

    Sorry Daryl, I don’t want to go all “Pipeline” on this but that little critter tells us a lot about water quality doesn’t it?

    Great read as usual , Thanks!

    I

    • Ray,

      There are a variety of zooplankton found in all of our waters. A variety of Daphnia and closely related zooplankton are common. Water quality certainly does impact algae and zooplankton numbers and types, but Daphnia are not necessarily indicators of high quality habitats. Daphnia and similar zooplankton are some of the largest zooplankton and are highly preferred by small fish. Typically as those large zooplankton are “grazed” down, other types of smaller zooplankton tend to dominate.

      I do not know if that answers all your questions, follow up with more!

      Daryl B.

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