Barbs and Backlashes

Fall spawning? by Nebraska Game and Parks Commission
October 23, 2009, 10:09 am
Filed under: Fishing | Tags:

I was over to Omaha last Saturday morning to be a guest on Greg Wagner’s radio show on 1620 AM, .  Greg does that show every Saturday morning at 9:00 a.m. and it is a hoot.  If you want to read more of Greg’s rambling, be sure to check out his blog, .  Anyway we had a call from a buddy of ours, a member of the Nebraska Walleye Association, , who was up on the Missouri River snagging paddlefish and catching some walleye and sauger.  He asked a question that Greg and I answered on the air, but I felt like I did not give the best answer I could.  So, I did a little research and sent an e-mail this week to give him a more complete answer.  Now, if I can quit rambling and dropping names, let me share some of that with you.

Have you ever harvested some fish in the fall and when you were cleaning those fish noticed eggs?  What’s up with that?  I am often asked if those fish are going to spawn in the fall?  Nope, that is not it at all.  We do have some strains of brown and brook trout in Nebraska that spawn in the fall, but other than that, all of the other species spawn in the spring or summer.  So why would they have eggs in the fall?  Settle in for a little fish biology lesson.  Fish are poikilotherms; their body temperature is essentially the same as their environment (let me digress for a second, research has shown that some species of large, ocean, predator fish can actually have a body temperature warmer than their environment, but that is a whole ‘nother discussion and none of those big predators swim Nebraska waters).  I do not like to say fish are “cold-blooded” even though that is the most commonly used term to describe poikilotherms.  That is mostly because I am a pointy-headed fisheries biologist, but think about it, in the middle of August when the water temperature is 84 degrees F they are not “cold-blooded”.

Production of eggs and sperm, gametes, requires a lot of energy.  One reason fish stay active and feed as much as possible in the fall is to ingest extra energy to prepare for the winter and to begin the development of eggs and sperm for the next spring’s spawn.  Different species of fish function at peak efficiency at different temperatures, but generally the colder the water, the slower the metabolism rate.  That means that during the winter the development of gametes is essentially “on hold”.  Fish begin development of eggs and sperm in late summer and through the fall, then there is little development of those gametes during the winter.  Depending on the species of fish and their spawning season, next spring the eggs and sperm will finish maturing and then comes the spawn!  If you look close you will see the milt sacs in males in the fall as well as the eggs you can find in female fish.  They do not spawn in the fall, that is next year’s hatch!

Let me mention something else that it interesting about the development of fish eggs and sperm.  In some species of cool-water fish, yellow perch and walleyes for example, it has been shown that even though there is little or no growth of the sex products during the winter, those species actually need a certain period of time during the winter for their gametes to develop properly.  If the winter is not cold enough, does not last long enough, the quality and survivability of eggs and sperm of those cool-water species is reduced.  That is one reason those cool-water species do not thrive in warmer environments.  Nebraska is a state with a huge gradient in climate from north and west to south and east.  Yellow perch do not perform well in southern and eastern Nebraska waters while some of our north-central and northwestern waters can have excellent yellow perch fisheries.  It is possible that yellow perch do not thrive in southern and southeastern Nebraska waters because the winters just are not long enough nor cold enough.  That also could apply to other cool-water species like walleye and northern pike in some of the warmer regions of the state.  Winters not long enough???? Who would have ever thought?

This IS one of our fall spawning fish in Nebraska.  This 13-inch male brook trout in full spawning colors was caught in October from Soldier's Creek in Nebraska's Pine Ridge.  It is not the biggest fish I have caught, but it is one of my best trophies!

This IS one of our fall spawning fish in Nebraska. This 13-inch male brook trout in full spawning colors was caught in October from Soldier's Creek in Nebraska's Pine Ridge. It is not the biggest fish I have caught, but it is one of my best trophies!


2 Comments so far
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That Trout photo was really gorgeous!

Comment by Pat Engelhard

I was so close to not getting any photo of that fish! I spotted that trout before I caught it; he was actually with a larger fish, a female I imagine, but I knew as soon as I saw him I wanted that fish. He was gorgeous. I literally crawled on my hands and knees to get into casting position without spooking the fish. After gently dropping my line in the current, that big beautiful brookie eased forward and took the bait! I landed him, immediately got the camera out, clicked one frame and as I advanced the film for another shot I discovered that I was at the end of the roll! Arrrrrggggghhhhhh! I made a special trip to a film shop with that roll of film and told them there might be one exposure at the very end that might not be a full frame exposure, but if they could get that exposure I would really appreciate it. Thank goodness they did!

That is part of the story behind my saying that is one of my best trophies ever!

Daryl B.

Comment by Daryl Bauer

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