The latest research from the 2000 Black Bass Symposium.

Florida’s Lake Kissimmee is a case in point. Until the 1960s, Kissimmee’s water level fluctuated up to 10 feet. This natural fluctuation was beneficial. During high water, weedgrowth flourished. During low water, it died back, and the shoreline dried. After water levels were artificially stabilized, however, plants flourished to excess.

According to Dr. Mike Allen and Kimberly Tugend, researchers at the University of Florida’s Department of Fisheries and Aquatic Sciences, hydrilla, pickerelweed, cattail, smartweed, and water primrose have choked shallow shoreline zones, and young bass have suffered.

Allen and Tugend studied large-scale habitat enhancement projects on managed and unmanaged sections of Lake Kissimmee. In November 1995, the lake was drawn down and the weeds removed from almost 20 miles of shoreline. The substrate also was scraped clean. Results were immediate and amazing.

Dissolved oxygen concentrations were higher in the enhanced areas (over 6 mg/L) in all daytime samples. Values in the thick, weedy, untouched areas dropped below 2 mg/L, below the level considered dangerous to bass.

Not a single young largemouth was sampled from the weedy control areas, while the density of young bass in the enhanced areas ranged from 40 to 140 fish per acre. Not only were there more young largemouth in the improved habitat areas, but also the fish were bigger, fatter, and more fit. Some yearlings were as long as 7 inches.

In enhanced areas, bass were eating small fish within weeks of hatching. By the following spring, up to 85 percent of their diet was fish instead of invertebrates. These results confirmed findings from other Florida lakes where young bass in weed-free waters consumed fish when they were only three inches long, while bass in highly vegetated lakes didn’t eat fish until they were twice that size. Even in subtropical Florida, the survival of young largemouth bass over the first winter is positively related to their size and growth rate. Clearly, the bass in the enhanced areas of Lake Kissimmee had a kick start on life.

Allen and Tugend also discovered that moderate densities of grass provide food and protection from predators. Densely matted weeds, on the other hand, are too much of a good thing, reducing feeding efficiency and growth.

They suggest that bass managers further study ways to efficiently and effectively manage vegetation, keeping it in check in fertile lakes where natural water fluctuations are blocked, and creating intermediate levels of weedgrowth in reservoirs where vegetation and natural woody habitat are sparse.

If We Build It, They Will Come

Bass managers have long sought to improve fishing by creating cover in shallow areas where bass nest. In places like Bull Shoals Reservoir in Arkansas and some inland lakes in Wisconsin, the practice has been successful. In other places, though, it hasn’t.

Researchers from Michigan’s Grand Valley State University and Haskell Indian Nations University in Kansas studied and compared over 650 bass nests in such disparate places as a small Arkansas reservoir, research ponds in Kansas, and a kettle lake in Michigan.

They discovered that regardless of geography or lake type, male largemouths built nests within a narrow range of water depth, substrate, and cover types. Four feet was the average water depth and medium textured sand and gravel was the preferred bottom. No great surprises. But then things got interesting.