walleyecrazy839 wrote:

Craig do you have any studys,on how many and if so what spiecies of fish the outflow on our lakes have? Otherwise how many of each fish go out the tubes during these high water years.Does it effect one spicies more than another? Nick

Nick,

Timing has much to do with what species and how many will be lost during release events.  Obviously if high release rates occur during mid-March to mid-April then walleye are highly likely to be flushed from a reservoir since many are concentrated along the dam for the spawn.  Walleye do like to 'go with the flow' which is one reason why sauger and saugeye have done well in waters that walleye failed.  Sauger/saugeye are less likely to flush out than walleye making them a better choice in high flow through waters.

Scott Waters, KDWP fish bio in Region 1, did a study a few years back on fish entrainment rates at Lovewell Reservoir.  He basically looked at all fish lost through the irrigation releases at the reservoir over a 3-year period.  It would be difficult to extrapolate the fish losses that Scott found during irrigation releases at Lovewell to flood storage evacuation at another lake.  The irrigation releases were lower rates over extended periods while flood storage evacuations can be very high durations over much shortage period.  I don't know of any Kansas studies looking at fish losses during flood storage releases but it is definitely a concern to fish managers within the state.

I'll do some digging around and I'll post back if I find some good species composition losses from Scott's study.

walleyecrazy839 wrote:

Thanks Craig, Our lakes can't afford to loose to many Walleye seems like the numbers are down for most all the lakes. Marion seems to be the most consistant number and size wise. Nick

Nick,

Here is the abstract from a study by Scott Waters, KDWP Fisheries Biologist at Glen Elder, which gives information on fish losses during irrigation releases.  These losses will differ from what other reservoirs would see from releases during flood events which could be of much higher release rates but this study will give you an idea of what can be lost.  I hope you find the information useful. 


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Fish Entrainment in the Courtland Canal Below Lovewell Reservoir, Kansas April 2008.

Abstract— Growing concern from anglers and department employees regarding the potential negative impact of fish entrainment within the irrigation canal on the Lovewell Reservoir fishery led to the development of a multi-year study to estimate entrainment rates and associated indices during the 2005-2007 irrigation seasons.  Irrigation releases began in mid-June and continued through mid- or late August each year.  Sampling occurred throughout the release schedule and during different segments of the day.  During sample periods, we collected virtually all of the fish entrained during either nighttime samples collected between 1500-0300 or daytime samples collected from 0300-1500.  Total releases during the three-year study averaged 29,170 acre-ft, well below the previous 10-year average of 47,251 acre-ft.    Estimated number of fish entrained varied with an estimated 5.5 million in 2005, 2.9 million in 2006, and 6.1 million in 2007.  Species composition was consistent each year with gizzard shad Dorosoma cepdianum accounting for 77-98% of the entrained fish, freshwater drum Aplodinotus grunniens varied between 2 and 15%, crappie Pomoxis spp. accounted for 0.3 to 8%, and walleye Sander vitreus and white bass Morone chrysops were each less than 1%.  Entrainment rates varied both diurnally and seasonally.  Fluctuating release rates due to water availability or recent rainfall events controlled entrainment rates throughout the irrigation season each year.  Initial releases triggered gizzard shad and other species to migrate to the outflow, become entrained, and yield the highest rates observed each year.  Fluctuations throughout the irrigation season also led to increased catches, but the highest entrainment rates were nearly always during the first four to five weeks of the season.  Diurnally, highest entrainment rates for sportfish species (walleye, crappie, and white bass) were usually during the evening and early morning hours between 1800 and 0600.  Gizzard shad exhibited a less predictable pattern of entrainment.  Highest rates in 2005 were between 1500 and 2100, in 2006 the 0600 to 15000 period had the highest rates, and two discernable peaks were evident in 2007 between 0300 and 0900, and 1500 and 1800.  Results of the three years of sampling indicate a fish barrier device, alteration in dam operation procedures, or post-irrigation mitigated fish stockings may be useful for improving the Lovewell Reservoir fishery.  The negative effect of entrainment on year class strength of crappie, walleye, and gizzard shad was evident based on standard reservoir sampling and entrainment estimates.  Installation of a fish barrier may be the best management option to help reduce entrainment rates and enhance the Lovewell Reservoir fishery.