Big Indiana Bass

     Effects of Reservoir Drawdowns and the Expansion of Hydrilla Coverage on Year-Class Strength of Largemouth Bass (Nagid, et al.): Four of the six cohorts produced during drawdowns were strong, whereas the majority of cohorts produced when pool levels were at normal depths were average to weak.

     Swimming muscles power suction feeding in largemouth bass (Camp, et al.): the cranial muscles of these fishes are relatively small and may not be able to produce enough power for suction expansion. The axial swimming muscles of these fishes also attach to the feeding apparatus and have the potential to generate mouth expansion. Because of their large size, these axial muscles could contribute substantial power to suction feeding. Peak expansion powers for all but the weakest strikes far exceeded the maximum power capacity of the cranial muscles. The axial muscles did not merely contribute but were the primary source of suction expansion power and generated up to 95% of peak expansion power

     Response of largemouth bass (Micropterus salmoides ) from different thermal environments to increased water temperature  (Mulhollem, et al.): One group of largemouth bass inhabited thermally enhanced reservoirs (used for power plant cooling), with water temperatures typically 4-9 °F warmer than nearby reservoirs. We tested fish for chronic thermal maxima and reaction to an 15 °F heat shock using three common physiological indices of stress. We observed no evidence of differences between groups in thermal maxima. We observed no differences in thermal maxima between fish from artificially warmed and natural systems. Our results disagree with (previous) research...

     Dispersal Patterns of Coastal Largemouth Bass in Response to Tournament Displacement (Brown, et al.): We examined the effects of transport distance and tournament handling stress on dispersal of 40 largemouth bass via telemetry from May 2012 to September 2013 in the Albemarle Sound system of eastern North Carolina. Largemouth bass were captured from four tributaries of Albemarle Sound and transported 10–28 miles to a central release point before being acoustically tagged and released. Our findings indicate little evidence of long-term stockpiling (i.e., fish remaining close to release point); 57% of displaced largemouth bass dispersed more than .3 miles (1,640 feet) from the release point within 7 d and 87% within 21 d postrelease. Half of those that emigrated from Edenton Bay returned to their capture location. However, no largemouth bass displaced > 20 miles returned to their capture locations, suggesting that long-distance displacement inhibits return. Fishing (2.8%) and nonharvest mortality (0.5%) were low throughout this study except for peaks observed during late spring (42.9%) and early summer (25.1%) of 2013.

     Estimating Capture and Mortality Rates of Largemouth Bass at Guntersville and Wheeler Reservoir, Alabama (Jeff Buckingham): Catch-and-release angling for largemouth bass has substantially increased since the 1980s, yet few studies have assessed the population-level consequences of these activities.  Guntersville and Wheeler Reservoirs, Alabama, are nationally known largemouth bass fishing destinations with high levels of angling effort and high rates of voluntary release (>85%).  We used a variable reward tagging study to estimate rates of capture, release, mortality, and angler reporting of tagged largemouth bass at these reservoirs.  Separate estimates were obtained for non-tournament release, tournament release, and harvest fisheries to evaluate the relative magnitude of potential population impacts among these fishery sectors.  Preliminary results from the first year of the study suggest that 44% of largemouth bass at Guntersville and 31% at Wheeler Reservoir were captured by anglers in 2014.  Harvest rates were 6% at Guntersville and 2% at Wheeler.  Competitive tournaments captured 10% of largemouth bass at Guntersville and 12% at Wheeler.  Tag reporting rates were lower for fish caught in competitive tournaments than that for non-tournament captures.  The estimated instantaneous natural mortality rate was 0.40/yr and did not differ between reservoirs.

The following image was taken from a poster at this spring's Midwest Fish & Wildlife Conference. It shows the comparison of smallmouth bass diets and respective lengths of preyfish consumed from two different lakes. Pickerel Lake and Clear Lake bass consumed bluegill, crappie and yellow perch. The red lines indicate the percent of the overall sizes of prey that were vulnerable to predation, while the black columns represent the actual size of the respective preyfish population. Anything left or under the red line is vulnerable, while anything outside (right/above) the red line was not. The numbers along the bottom were prey length in millimeters. For simple conversion, figure 25 millimeters per inch, so 100 mm mark would be prey roughly 4 inches long.

You can play with the numbers and comparison, but as an example, you'll notice that on both lakes, smallmouth ate bluegill that were always smaller than the other two preyfish consumed. This is likely because bluegill are a deep bodied fish with stiff dorsal fins/spines. As such, once a bluegill got much over 3"-4" long, it was basically immune from being consumed by the smallmouth in these lakes.

In contrast, a look at the lengths of crappie and yellow perch consumed at Clear Lake show that those preyfish were not completely safe until they reached a length of nearly 9 inches. So while most of the crappie population on Clear lake was safe from consumption due to the overall quality size of fish (crappie) in the lake, nearly all the yellow perch were potential food items. "Food for thought."

An interesting graphic showing the approximate lifespan of common items thrown in the water. Not unusual to see about half of these items around a lake many weekends. Not certain if saltwater would break these down faster than if they were thrown into freshwater.