Fisheries Report December 2016 Prepared by Logan Cowan and Matthew Ward Introduction This fishery survey report covers the fishery survey we conducted on the 6 th and 7th of December, 2016. As always, we appreciate the opportunity to serve you and welcome any questions that the board members or shareholders may have. First, we will list our observations and then we will give you our recommendations. Recommendations are aimed at helping s fishery reach its potential as a recreational fishery. Note that we will be comparing the 2015 data to that collected in the last fishery survey and as such we will note the trends we see. In broad terms, your adult fish have grown substantially in size and remain quite healthy. This year s spawn was substantial but did drop some from what was noted last year. The large number of small bass from last year s spawn likely reduced recruitment from this year s spawn. The lake s forage continues to consist of large numbers of sunfish, gizzard shad, brook sliver sides, but far fewer threadfin shad this year than last (assuming we didn t just miss the fish during sampling, which can happen if they are schooling in deep water). Vegetation coverage is beneficial to your fish and water quality is at the highest level we have yet seen. Observations Water Quality In 2016, we checked water quality parameters during our fisheries survey. PH usually measured 6.5 and alkalinity measured between 15 and 20 mg/l. These readings are marginally acceptable though as expected considering the runoff that has been experienced in the last two years. ph Dam-end of Lake Mid Lake Silvey Bridge Desired Range 2016 6-6.5 5.5-6.0 5.5-6.0 6.5-8.5 2015 6.5-7.0 5.5-7.0 5.0-6.5 2014 7.25-7.5 7.25 7.25-7.5 2013 6.25-7.5 6.0 6.0-6.5 2008 7.0 6.5 6.2 Alkalinity Dam-end of Lake Mid Lake Silvey Bridge Desired Range 2016 38 mg/l 41 mg/l 44 mg/l >20mg/L 2015 15 mg/l 25 mg/l 15 mg/l 2014 25 mg/l 25 mg/l 25 mg/l 2013 15-25 mg/l 20 mg/l 10-25 mg/l 2008 13 mg/l 13 mg/l 8 mg/l
Page 2 of 21 Hardness o Total hardness had dropped to 32mg/L. This hardness is acceptable for a healthy fishery. Visibility o Visibility varied from the dam up to Silvey bridge as usual. Measurements varied from 8-96. In general, the lake was relatively clear but as expected for this time of year. No particular reduction in plankton growth was noted during our vegetation surveys this year. Vegetation As usual s vegetation was very diverse. This year s growth was fairly similar to that observed last year, except for some submerged vegetation which has not been noticed for years being found below Silvey Bridge. All of this growth was minor and far from being a cause for concern, presented a healthy development for the lake s fishery. Submerged vegetation was generally scarce in the main body of the lake, but mats of submerged vegetation topped with water primrose and alligator weed persisted above Silvey Bridge. Marginal vegetation remains extensive with spot treatments having kept growth within bounds. Growth is well distributed around the lake and does not impede recreational access. Submersed vegetation consisted mostly of coontail and slender spike rush. I suspect that variable-leaf watermilfoil remains in the lake below Silvey Bridge, but we did not happen across any mats during our vegetation surveys over the past two years. A very small amounts of filamentous algae and hydrilla was also noted this year. Emergent vegetation consisted of yellow waterlily, lotus, water primrose, alligator weed, southern wild rice, maiden cane, rushes, pickerelweed, arrowhead, elephant ear, smartweed, water willow, buttonbush, cattails, bald cypress, lizard s tail, white waterlily, torpedo grass, pennywort, and willows. The pictures below show some of the lake s plants, but these pictures do not represent an exhaustive photographic library of s plants. Pennywort Coontail
Page 3 of 21 Maiden Cane Pickerelweed Southern wild rice Arrowhead White water lily Smart weed
Page 4 of 21 Aside for Fishermen Last year s report gave a detailed set of recommendations for fishing various forms of vegetation and habitat. This year, I decided to include a brief piece about more specific lure selection. Sunfish Imitations Sunfish will tend to hang out in shallow weedy waters, when they are small, when they are spawning, and when they are foraging. The remainder of their time is spent in deeper water, where they can escape predation and remain out of sight of hungry predators. Usually large swimbaits and crankbaits will do a good job of imitating these deep water sunnies while spinnerbaits, chatter baits, and lipless or shallow diving crankbaits will adequately imitate sunfish in shallow water. The most important spawning seasons occur in the spring and the fall, but sunfish like bluegill or green sunfish will spawn all summer long. Males become brightly colored during the spawn while females and males out of spawn have more muted colors. I tend to prefer, chartreuse, red, yellow, and bright blue/turquoise to imitate spawning males and green, brown, muted blue, and rust to imitate females and sunfish out of the spawn. Firetiger is a particular color pattern which was intended to imitate the male spawning sunfish. When fishing sunfish imitations, know that the larger the lure the bigger of a fish you will generally catch. Bass over 8 lbs can often swallow sunfish that weight up to a pound and may measure as much as 10 in length. That being said, bass metabolisms slow during the winter, so you may still catch giant bass during the winter on relatively small sunfish imitations. Crayfish Imitations Crayfish will live throughout the lake, but especially enjoy riprap and other hard substrate like timber. They will generally spend most of their lives hiding in tight spaces, but they do adventure out into the open, particularly during mating seasons. There are two mating seasons one in the spring and another in the fall. Different crayfish species vary a bit on the timing and location of their spawns but these are the best times of year to fish crayfish patterned lures. Generally speaking crawfish become dull colored as they approach the spawns, undergoing molt after the spawn is completed. Their colors are brightest after the molt. This means that you should fish dull colored crayfish imitations prior to and during the spawn, switching to bright colors post spawn. Know that soft plastic imitations will more accurately reflect molted crayfish while hard baits will tend to have more of the texture of spawning crayfish. Threadfin Shad Imitations Threadfin shad are open water denizens and as such will generally be found schooling off of major points, channels, and ridges in the main lake. The exception to this is during warm spells in the winter when threadfin shad will tend to congregate in the upper ends of the lake s coves, where they will find the warmest water in the lake. At, they may also hang around the warm water discharge canal. They will tend to go deep during the middle of the day and move to the shallows at night. This movement helps to protect them from predation during the day and allows them to follow the plankton they feed on. Plankton tend to migrate down during the day to avoid predation, traveling up to the water s surface at dawn and dusk. Threadfin shad spawn in spring and a bit in the fall. This spawning activity is usually visible, with threadfin shad breaking the water s surface along main lake shorelines. This activity occurs at first light and again at dusk. This is a great time to fish the lake s banks.
Page 5 of 21 Threadfin shad populations tend to peak in late summer and on into the fall. During this time of year, you can often chase schools of shad which break the water s surface as they are hounded by bass. A pair of binoculars and a good shad imitating lure are your ticket to success. Because you will generally be covering a lot of water when imitating threadfin shad, you should choose lures that are easy to cast a long way. Typically, jigging spoons, regular spoons, rattle traps, and small swimbaits will get the nod from experienced fishermen. Structure/Habitat As mentioned in the past, is made up of a wide variety of habitats which include large expanses of standing timber, windswept sandy points, shallow bayous, marshy wetlands, flooded living timber (e.g. cypress and willow trees), sand bars, an island, open water, quiet coves with various forms of vegetation, docks (some with added timber to attract fish) and rip-rap (rocky shorelines). Total cover is sufficient for a healthy fishery to subsist in the lake. Fish This year s survey revealed good fish species diversity as usual. Overall species diversity was similar to that observed in our previous surveys. Species distribution continues to vary with certain species being found scattered throughout the lake, while other species were concentrated in certain habitat types. The variety of habitat continues to ensure species diversity because of the variety of ecological niches available. I have included pictures of the fish observed along with common names and a brief description of the species abundance and the kind of habitat the fish seemed to prefer in. Redear Sunfish Redear sunfish were abundant in this year s survey. Redear where found throughout most of the lake. Medium, large and giant redear were abundant, while small redear were common. Threadfin Shad Threadfin shad were common and found only in the upper ends of creek arms. All of the shad observed where quite small indicating some recruitment. Populations are likely much higher than was observed as sampling is a bit hit or miss for the species.
Page 6 of 21 Redbreast Sunfish Redbreast were common in most of the shallow waters below Silvey Bridge. Redbreast numbers were much higher this year than last. Gizzard Shad Gizzard shad are quite abundant throughout the lake. Gizzard shad were generally found in the shallows. Warmouth Warmouth sunfish were not common with only a few individuals being sampled in shallow water. Flathead Catfish Flathead catfish are more rare than channel catfish, though we did sample one individual in the gillnet. The one measured 20 and weighted 2.66lbs. Channel Catfish Channel catfish were rare with 3 being found in the gillnet, and 5 via electrofishing. Channel catfish measured from 18-28.5 and weighed up to 12.45 lbs. Channel catfish sampled were generally healthy. White Crappie White Crappie appear to be slightly more abundant than black crappie and slightly larger according to our findings. This year, 10 white crappie were sampled, the largest being 14 and weighing 1.34lbs.
Page 7 of 21 Black Crappie Black crappie are often under-represented in an electrofishing survey, but we sampled 7 individuals. The largest measured 11.75 and weighed 0.79 lbs. Black crappie average Wr was 0.90. White Bass White bass were not sampled while electrofishing, but one was found in the gillnet. White bass appear to be rare this year. The one we found measured 16 and weighed 2.55 lbs. Bluegill Bluegill, the most abundant sunfish, were found scattered around the lake in a wide variety of habitats. Small and medium sized bluegill were abundant while large bluegill were common. Spotted sunfish Were rare this year with only two individuals found in our survey. Triploid Grass Carp A handful of triploid grass carp were observed during our survey. Sampled grass carp were large. Tilapia Were rare this year with very few found being sampled.
Page 8 of 21 Chain Pickerel Spotted Sucker Spotted suckers were common throughout the lake, with most being sampled above silvey bridge. Chain pickerel have been relatively elusive in most of our fishery surveys, this year we found 2. The largest measured 15.5 and weighed 0.77 lbs. Chain pickerel held tightly to vegetation Spotted Bass Once again, we sampled a handful of spotted bass in this year s survey. Spotted bass were rare to common. Spotted bass were concentrated around hard substrate and especially near the outflow canal. Spotted bass juveniles were found along with individuals up to 13.5 inches in length weighing up to 1.30lbs. Spotted Bass can be distinguished from largemouth by their connected dorsal fin and the lines of dots present on their ventral surfaces. Spotted bass jaws reach the back of the bass eye, when closed while largemouth jaws extend behind their eyes. All spotted bass lengths and weights are reported with largemouth bass data shown below. Common Carp, Bowfin, and Spotted Gar Many of these fish were found and harvested during our survey. Bowfin and gar were scattered around the lake, being found amid a variety of aquatic vegetation types. Common carp were mostly found in shallow water above Silvey Bridge. We harvested 169 bowfin, 36 gar, and 6 common carp.
Page 9 of 21 Largemouth Bass Largemouth bass were abundant, being by far the most common predatory fish in the lake. Largemouth were found throughout the lake in a variety of habitats. All sampled fish were weighed and measured with all data reported below. Sampled fish varied in length from fingerling bass to the 22.25, 8 lb. 15oz. fish shown above. Similarly, to last year, many of the bass sampled were schooled together. This is a common occurrence during the fall and enables bass to more efficiently prey upon schooling forage such as threadfin shad. A particularly large number of bass were found above Silvey bridge. Bass average Wr declined very slightly from last year. Average Wr was 0.94. 72% of the bass measured 14-20 long, 7.6% of bass weighed in at over 4lbs.
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Page 11 of 21 Analysis/Recommendations Water quality Despite the heavy run-off the lake has experienced the last few years, water quality is at the highest level we have yet seen. This should result in increased fishery productivity in the coming years. Since we have no historical record of floods improving water quality we are left to assume that mining operations and or the lime applications you have conducted have resulted in the current water quality. This being said, we are not ready to stop recommending lime applications until we see consistent improvement over time. We continue to encourage you to employ small scale applications of lime to moderate ph shifts. We again recommend that lime should be applied to the lake at water influx points in particular (shoot for 100 tons or more, annually, if possible). As previously stated, all catastrophic ph drops cannot be mitigated by limited lime applications but, the regularity of partial fish kills can be reduced and fish may be afforded a bit more time to vacate areas that are likely to experience ph drops. The likelihood of a ph drop is dramatically less this coming year than it has been in the past. Vegetation We compared vegetation species noted this year to those noted in previous surveys. Vegetation diversity remains very high with no one species of vegetation being particularly problematic. Submersed vegetation remained well under control while marginal vegetation remained static. Spot treatments aimed at improving recreational access were sufficient to keep vegetation growth under control. Grass carp appear to be keeping all forms of submersed vegetation growth in check on the main body of the lake. For now, continued monitoring is the best way to remain proactive with s vegetation growth. At this time, I expect that marginal spot treatments will continue to be sufficient to keep vegetation growth under control in 2016. Looking forward, vegetation growth should begin to expand as grass carp mortality thins their numbers. Observation YEAR VEGETATION TYPE 2002 2008 2013 2014 2015 2016 Alligator Weed * yes yes yes yes yes yes American Lotus yes yes no yes yes no Arrowhead yes no yes yes yes yes Bald Cypress yes yes yes yes yes yes Bladderwort no yes yes yes yes no Bur Marigold yes no no yes yes no Buttonbush yes no yes yes yes yes Cattails no no yes yes no yes Coontail no no yes yes yes yes Chara no no yes yes no no Elephant Ear yes yes yes yes
Page 12 of 21 Filamentous Algae no yes yes yes yes yes Hydrilla no yes yes no yes yes Lizard's Tail yes yes yes yes Maiden Cane no no yes yes yes yes Nitella Algae no yes yes yes no no Parrotfeather no yes yes no no yes Pennywort no yes no yes yes yes Pickerel Weed yes no yes yes yes yes Rushes yes yes yes yes Southern Wild Rice yes yes yes yes yes yes Slender Spikerush no no yes yes yes yes Smartweed yes yes yes yes yes yes Torpedograss yes no no Variable-leaf Pondweed yes yes yes no Variable-leaf Watermilfoil no yes yes yes no no Water-Willow yes yes no yes Water Primrose yes yes yes yes yes yes Water Shield yes no yes no no no White Water Lily no no yes yes yes yes Willow yes yes yes yes yes yes Yellow Water Lilly yes yes yes yes yes yes *Exotic vegetation appears in red above. Structure/Habitat My recommendation for habitat improvement remains the same. contains adequate cover for your fish. This being said, it would be a good idea to encourage fish to frequent the areas that are targeted by fishermen or that could be easily targeted by fishermen. Towards this goal, I continue to recommend some deep water fish habitat be constructed off of Bikini Island and some shallow water habitat be placed on the cove side of Firecracker Park. Additionally, encouraging residents to add brush to their docks should improve angler success and overall angler satisfaction with the lake. Habitat should always be designed to serve the purposes of both the fish and the fishermen. Fish Fish occurrence by species is listed below, along with data from last year s survey. Overall, the fishery survey revealed good fish diversity as usual. As stated before, this diversity is a testament to the varied habitat that offers to the fish it contains. Note that actual abundance is likely different than observed abundance. The biggest differences we noted in our 2016 fishery survey was the increased size of largemouth bass; numbers of gar, bowfin, and brook silversides; lack of numbers of threadfin shad.
Page 13 of 21 Fish Species Composition for Sampling conducted via electrofishing and gillnetting Species Relative Density Year 2015 2016 brook silverside common abundant threadfin shad abundant rare redbreast sunfish common common redear sunfish common abundant bluegill abundant common longear sunfish rare none orange-spotted sunfish rare rare warmouth rare rare tilapia rare rare gizzard shad abundant abundant spotted sucker common rare creek chubsucker common none bullhead rare none channel catfish common rare flathead catfish rare rare common carp common common triploid grass carp rare common spotted gar common abundant bowfin abundant abundant hybrid striped bass rare none white bass none rare yellow bass none none chain pickerel rare rare grass pickerel rare none black crappie rare common white crappie none common spotted bass rare rare largemouth bass abundant abundant Looking a bit more intently at the largemouth bass data collected, we can calculate the bass population s PSD and RSD s for the 14, 16, and 18 inch length classes. Average weights and Wr are also reported on the following page. All data is contrasted with that obtained during our 2013, 2014, and 2015 surveys. PSD reflects the percentage of your adult bass population that are reproductively mature (percent of fish over 12 out of all fish measuring over 8 ). RSD shows the percent of fish over or equal to a specified length out of all bass measuring at least 8 in length. As you can see, your fish are slightly less healthy this year as compared to 2015 (Wr is 0.94 as opposed to 0.96), but are still in better shape than 2013 or 2014. Additionally, there were many less YOY (young-of-the-year) found in this year s survey, there are far more fish over 14 inches in length than there have been over the last couple of years with the RSD 14 being at 75% (a 21% increase over last year and 31% increase from 2013), and bass over 8 in length average 1.92 lbs (a 14% increase in weight since last year).
Page 14 of 21 Table 3: Largemouth Bass Population Indices Parameter Survey Year 2013 2014 2015 2016 Number 177 105 157 169 PSD 57% 74% 71% 84% RSD 14 44% 49% 54% 75% RSD 16 24% 33% 27% 44% RSD 18 8% 20% 10% 30% Avg. Wt. 1.41 lbs 1.42 lbs 1.62 lbs 1.92 lbs Avg. Wr 0.92 0.92 0.96 0.94 Based on our findings we recommend the following fisheries management strategies. My recommendations are broken down by species category. I have kept the discussion of how to manage your hatchery ponds at the end of the report. Forage Fish The following is an aside maintained from past survey reports. Forage populations remain quite diverse. The array of baitfish species, as mentioned in the past, is good for your bass population. Each baitfish has a different niche (or role) in the lake and thus turns different lower level consumers and producers into bass food. Redear convert shelled creatures into bass food, turning both snails and mussels into bass food. Most other species of sunfish convert aquatic insects and small fish into bass food. Threadfin shad convert plankton into bass food. Gizzard shad convert benthic organisms into bass food All of these prey species work together to provide a far more stable food supply for your bass than would be experienced in the presence of just one or two forage species. To repeat the example given in our last survey, when an environmental factor causes plankton bloom densities to diminish, allowing more vegetative plant growth (increased light penetration) bass can begin to feed less on threadfin shad and begin to feed more on the redear sunfish that pick snails off of underwater vegetation. This being said, not all forage species are created alike and some sunfish with larger mouths actually compete directly with your bass for food. As such, green sunfish and warmouth can compete with bass for the same food items. Fortunately our survey revealed no green sunfish and just a couple of warmouth. In a perfect world, fishermen would harvest green sunfish and warmouth when they catch them. To increase the forage base in, one or more of the following steps should be taken. Encourage residents to feed fish. They may either hand feed fish or install automatic fish feeders. The feeders you have purchased and placed along the outflow canal should be filled from March through November. We recommend that you feed Purina s Sportfish Aquamax 500. If a resident is looking for an automatic feeder, we carry Texas Hunter Feeders and can direct ship these feeders to anyone who wants one (a bulk discount could be worked out if a large number of feeders were desired). Fish food generally adds 0.5 lbs of fish to your lake for every pound of fish food applied to the lake.
Page 15 of 21 We recommend that you continue supplemental stockings of bluegill, threadfin shad, or any other forage fish (through your rearing ponds: threadfin shad and tilapia are the best options for 2016). Encourage residents to sink additional brush piles around their docks, ensuring that brush piles are not in the way of boat traffic. Fresh brush piles help to protect some of your forage, helping to ensure adequate brood stock is preserved from year to year. Brush piles also have the side benefit of attracting fish to the areas that fishermen fish. We prefer cedars and various hardwoods for the task, but you can also use PVC, artificial prefabricated structures, or even stake beds (commonly used by crappie fishermen to attract crappie). We sell Honey Hole fish habitat for those looking for prefabricated structures. Add lime to encourage plankton growth which in turn will serve to feed a plethora of forage species which consume phytoplankton, zooplankton, and their predators. Finally, though many fish species are used by largemouth for food, certain size classes of those fish do not go to feed bass. For example, bluegill measuring in excess of 7 inches would be too large for all but the largest bass to consume. As such, you should encourage fishermen to harvest large sunfish when they catch them (sunfish measuring more than 7 inches in length). The removal of large sunfish means that smaller sunfish will have a greater food supply. Catfish Catfish were mostly observed through gill-netting and populations appeared to be significant though rather low as has been observed in the past. The gill-net sampled 3 and electrofishing 5 channel catfish to 28.5 inches in length. These catfish were healthy, indicating that their populations do not exceed s carrying capacity. In addition to the channel catfish, the gill-net yielded 1 flathead catfish that measured 20. Very little can be determined about the overall population of flathead with this small of a sample size but fish sampled indicate that a substantial flathead catfish population subsists in the lake. No bullhead catfish were sampled this year. As stated before, continuing supplemental stockings of channel catfish is the best way to improve recreational fishing opportunities for catfish fishermen on. Growing up small catfish in the rearing ponds is the best way to improve s population. Supplemental feeding with pelleted fish food in the outflow canal provides a significant benefit to your catfish. White Bass One white bass was found in the gill-net. Though this year s survey indicate that white bass populations are very poor, tightly schooling fish such as hybrids and white bass often prove to be difficult to survey and so populations might be similar to historic levels. If increased hybrid striped bass fishing success is desired by fishermen, you might consider stocking these fish from time to time (growing up small fish in the rearing ponds). That being said, not having large populations of hybrids or white bass will benefit your largemouth bass populations. Black and White Crappie Few crappie were found in our 2016 survey. A total of 6 black crappie and 10 white crappie were sampled and crappie measured up to 14 and weighed up to 1.34 lbs. As is the case with hybrid and
Page 16 of 21 white bass, schooling crappie are quite difficult to sample. The numbers and sizes of crappie we did capture indicate that overall, populations are low to moderate. Three techniques are advised to help you improve your crappie population. You should attempt to harvest down the undesirable predators, harvest large competing sunfish, and stock the lake with additional crappie (raising the crappie in the rearing ponds). To reduce predation on crappie, encourage fishermen to harvest gar, bowfin, white bass, and flathead catfish. To reduce competition with large sunfish, encourage fishermen to harvest all sunfish measuring over 7 inches in length. Chain Pickerel As normal only a few chain pickerel were sampled. This year we did sample a relatively large specimen which measured 15.5 and weighed 0.77lbs. Chain pickerel populations are expected to remain low. Since these native fish provide an oddity catch for bass fishermen and tend to maintain small populations, no harvest is needed for these fish. Grass Carp We sampled quite a few grass carp, most being seen above Silvey bridge during our fishery survey, but vegetation growth indicates that grass carp populations are acceptable at this time. Grass carp that we stocked in 2011 are now 5 years old. Their effective life is 10 years, so they are still in the prime of their effective lives. No additional stockings are expected to be needed for this coming year. Rough fish encompasses all those fish which are not typical targets of fishermen: o Common carp, are common throughout the lake, though fewer fish were sampled this year than last. We captured and removed 6 during the survey. These fish are not particularly harmful to your fishery, but do little to contribute to the lake. Common carp are omnivores, eating plants, aquatic insects, benthic organisms, crawfish Fishermen should be encouraged to harvest common carp when possible. Bowfishing is generally the best method for harvesting these fish. This being said, some people enjoy catching the fish on rod and reel. Common carp are nonnative fish which were stocked in most of our state waters a very long time ago. o 4 suckers were sampled in this year s survey. The population seems to have fallen this year, which may be due to the rise in the bowfin population. o Predatory non-game fish included spotted gar and bowfin. A substantial population of both gar and bowfin were found in the lake. This year we harvested a record 169 bowfin and 36 spotted gar. We also set our new record for the largest bowfin that we have sampled at 12.34 lbs. For the sake of your game fish, fishermen should harvest these fish when they encounter them. Both species consume some of the same forage as bass, crappie, and large catfish. Both species can be caught on rod and reel but both can be targeted by bow fishermen as well. This being said, note that personally speaking, I find bowfin quite enjoyable on rod and reel and so some residents might want to try catching bowfin on bass jigs fished along weed lines in the upper end of the lake or major coves. Remember not to lip these toothy creatures. Largemouth and spotted bass were abundant on the whole, though spotted bass are far less common than largemouth. Bass were spread out across the length classes though more evenly distributed than was the case last year. The bass PSD of 84% remains above the desired range of 40-60%, which indicates that
Page 17 of 21 recruitment remains a bit lower than ideal, but this high PSD also indicates that the vast majority of your bass are large enough for fishermen to target. Average Wr has decreased to 0.94 and remains just 6% off of the ideal of 1.0. This means that increased harvest recommendations have helped, over the course of multiple years, but to continue the positive trend, we plan to up your harvest recommendations a little bit more this year. Looking at your RSD values, your RSD 14 is higher this year than it has been in the past, indicating that there are large numbers of bass that measure 14 or longer. It is very encouraging to see your RSD 18 value higher as well, RSD 18 is at 30 % which is a 20% increase from last year. This means that 30% of the fish we sampled were larger than 18 inches in length. As mentioned in the past, we do not put a lot of stock in PSD and RSD values as these data are less informative in a diversified fishery like but, in general, I am pleased with the large number of bigger bass we found. To improve your bass fishery, we need to fatten your bass up just a bit more. To accomplish this you should harvest competing predatory fish populations as discussed above, you should work to increase forage populations as discussed under the forage fish section, and you should strongly encourage fishermen to pursue increased bass harvest. We recommend that the lake s harvest restrictions for bass be changed to allow fishermen to harvest 10 bass per person per day with no more than one fish over 17 inches in length being retained per day. There is no minimum length limit. I would encourage the fishing club to recommend that fishermen release bass over 17 in length but understand that some fishermen would like to keep a trophy fish. The lake will support the harvest of these larger fish as long as the majority of bass harvested are a good deal smaller. Finally, to maintain trophy genetics in the lake we continue to recommend that you rear and release pure Florida-strain bass. A single forage pond can be dedicated to this purpose. Terms ph is a measure of the concentration of hydrogen ions in water. Fish have a preferred ph range (generally 7-8.5) and ph shifts outside of that preferred range cause stress on those fish. ph changes on a daily basis unless buffered (see alkalinity and hardness) and this change also can increase stress on fish. The low ph observed in your lake is not unusual for east Texas and is presumably caused by decaying vegetative matter particularly in the upper end of the lake along with naturally low alkalinity. Alkalinity is a measure of the concentration of carbonates, bicarbonates, hydroxides and other weak bases whose primary biological function is buffering ph. Low alkalinity (<20 mg/l) allows for greater fluctuations in ph and thus increases stress on fish. Hardness is the measure of the concentration of calcium and magnesium ions in water. Hardness is also indicative of the buffering capacity of a body of water. When total hardness falls below 20mg/L, ph fluctuations increase with the same result as described above. Visibility is important because it lets us know how deep the littoral zone goes (the area of the lake s bottom that receives sunlight and thus the areas of your lake that are most prone to invasive plant growth) and lets us know how dense a plankton bloom is growing or how much suspended sediment exists. In the case of your lake, visibility is mostly determined by the density of your plankton bloom. In a perfect bass lake a visibility of 18-24 inches would be ideal. This would allow enough visibility for bass to be able to find and eat their food and would provide enough food for the base of the food chain to support very high carrying capacities.
Page 18 of 21 Exotic refers to any one of many plants and/or animals not native to Texas. Invasive is a term used to describe plants that are particularly known for rapid expansion in coverage and density. Length class frequency is a comparison of the relative abundance of bass of different lengths. Wr or relative weight is the weight of a bass of a given length divided by the weight of an ideal bass of that same length. When Wr = >1 your bass weigh exactly the right amount. They are neither overweight nor underweight and will likely have maximal growth curves. When Wr = 0.80 your bass are 20% underweight and will likely be stunted as they are not receiving all of the nutrition they need for optimum growth. A Wr between 0.95 and 1.05 is the general target range. Number describes the total number of bass collected by sampling. PSD describes the proportional stock density of your largemouth bass. This is the percent of your adult bass that measure over 12 in length. Ideal PSD will be between 40-60%. A high PSD indicates low recruitment, or in other words your bass would not be successfully spawning. If your PSD were low, then you would expect that you had very high mortality or your bass were not getting sufficient food for growth. RSDx is simply the relative stock density or percent of adult bass equal to or over x inches in length. Avg. Wt. is the average weight of bass captured during the survey. Avg. Wr is the average Wr of bass of all length classes. Nursery Pond Techniques As I have mentioned throughout the report, your nursery ponds are one of the best management tools you have for supplemental stocking of forage and game fish species. Plans for use of each nursery pond should be finalized early in the year. If it were up to me, I would suggest you rear: tilapia in ponds B and C; threadfin shad in pond D; black crappie in pond A; Florida largemouth bass in pond E; channel catfish in pond F. Pond care should occur as follows.
Page 19 of 21 A B D C E F If you are stocking adult fish in the hatchery ponds with hopes of them spawning so their offspring may be later stocked into, do the following: o Prior to filling ponds, ag-lime (CaCO3) should be added at a rate of 1-2 tons per surface acre. Lime will help maintain a healthy and stable ph during production thus maximizing productivity. o Ponds should be partially filled to approximately 1/3 of their full capacity prior to stocking. o Stock desired species to be cultured. If stocking largemouth bass or crappie, first stock 10 pounds fathead minnows per surface acre. Stock 10 adults of the species to be cultivated. If possible, pre-determine the sex of each and stock a 50/50 ratio. Brood fish should be chosen for their genetics. Texas Parks and Wildlife may be willing to supply some Operation World Record bass, otherwise, bass with Florida genetics should be chosen. Fish should be in place approximately one month prior to spawning. Bass should be in place by early March. Crappie should be in place by early February. To raise threadfin shad, you should harvest a few shad during the shad spawn in April, transferring these fish to the rearing pond. These fish will spawn through May, being ready for release by June when water temperatures might put too much stress on your threadfin shad population. Tilapia can be stocked as soon as they become available. You can stock a relatively small number of tilapia, allowing their prolific reproduction rates to allow you to produce a large number of the fish within a couple of months. You might consider stocking ponds B and C, releasing one pond after a month, stocking a few of the fish from the other pond in the first pond after it has been partially refilled. This process can be repeated with alternating ponds once every month, through the end of September when both ponds should be released into the lake. Bluegill should be stocked at a rate of 200 3-4 bluegill per surface acre. If channel catfish are to be spawned, stock 10 pair of adult channel catfish per surface acre. Install containers with relatively small openings though these containers should be
Page 20 of 21 large enough for two catfish to enter. Large diameter PVC with an end cap or buckets will do the trick. o Finish filling the ponds as the water temperatures warm to each species spawning temperature o Fish species such as bass or crappie that do not readily accept fish food should be sampled periodically to monitor growth and reproduction (done with a sampling seine). o Deter predators such as fish eating birds, snakes, and otters from your nursery ponds. o Add floating scrap lumber or other material that can be later removed for fathead minnow spawning habitat. Fathead minnows spawn by placing eggs beneath floating structure. Remember that fathead minnows are good forage for your rearing ponds, but are not intended to feed itself. o Add a high phosphorous fertilizer at a rate of 5 pounds per surface acre. Add additional fertilizer every 10 days to maintain a plankton bloom at approximately 18 visibility as measured by secchi disk or other suitable item. o Adult fish should be harvested after samples reveal suitable fry numbers are present. This is normally accomplished with a seine. If you are rearing bass or crappie, stock fathead minnows once the adult fish have been removed. Stock 10 lbs of fathead minnows per surface acre. o Feed supplemental feed as appropriate depending on the species. Feed as much as the fish will consume in a 3-5 minute feeding. Adjust the size of the feed distributed to coincide with the mouth size of the fish being fed. If you are utilizing the ponds to stock and grow out fingerling channel catfish, simply prepare the pond as above though fertilizer is not needed. Stock up to 1000 fingerlings per surface acre and feed as described above. If you are utilizing the ponds to stock and grow out fingerling bass or crappie, simply prepare the pond as above (including fertilizer) and stock: o 2 lbs of fathead minnows per surface acre in February or March o 200 fingerling bass or 800 small black crappie per surface acre, should be stocked in June or May respectively After harvesting each crop, drain the pond and inspect the bottom for accumulation of silt. If significant silt has accumulated, allow the pond to dry and disk the silt layer in the pond bottom to allow oxygen into the silt layer. This will help the organic silt to break down prior to re-filling the pond for the next crop. Conclusion As we have asserted in the past, is a truly exceptional lake. The varied habitats, scenery, and recreational opportunities are unmatched (to my knowledge) in Texas. While micromanagement is not practical in such a grand fishery, there are many useful techniques we have laid out that will serve to create a more desirable fishery. Of all the techniques discussed, angler harvest and nursery pond management are the most important tools to employ. Once again, we hope that this report helps you understand the state of the fishery and how to better manage your fish. We appreciate the opportunity to work with you. Summary of Fisheries Management Recommendations for
Page 21 of 21 Water Quality o Apply 100+ tons of lime to the upper end of the lake. o Monitor water quality. Vegetation o Do not harvest or stock additional triploid grass carp. o Continue to monitor vegetation in the main body of the lake on a monthly basis from April through September. o Continue to spot-treat marginal vegetation to ensure recreational access and maintain aesthetics. Structure/Habitat o Place deep water fish habitat off of Bikini Island. o Place shallow water habitat off of the cove side of Firecracker Park. o Encourage residents to add brush to their docks. Fish o Increase the forage base Encourage residents to feed fish with pelleted fish food Encourage fishermen to harvest green sunfish and warmouth Encourage fishermen to harvest any sunfish they catch that measure over 7 in length Continue supplemental stockings of forage from the hatchery ponds o Increase your channel catfish population Stock channel catfish that you rear in the nursery ponds Encourage residents to feed fish with pelleted fish food Continue feeding with the feeders that are located in the outflow canal Set harvest restrictions to 15 fish per person with the minimum harvest length set at 12 o Harvest your flathead catfish Since flatheads compete with your other desirable sportfish for food, we suggest you allow unlimited harvest of flathead catfish o Increase the crappie population Continue regular supplemental stockings through the hatchery ponds Set harvest restrictions to 15 fish per person per day with the minimum harvest length set at 10 o Reduce your rough fish population Harvest common carp, bowfin, and gar by encouraging fishing by rod and reel or bowfishing tackle. o Encourage the harvest of the smaller bass in order to leave more food for your larger bass Encourage fishermen to focus their harvest efforts on fish under 17 in length. Set harvest restrictions to the following: Fishermen may harvest up to 10 bass per person per day with no more than one fish over 17 being retained. o Rear the following in your nursery ponds: A: black crappie B and C: tilapia D: threadfin shad E: Florida largemouth F: channel catfish