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The St. Johns River Water Management District’s Surface Water Improvement and Management (SWIM) program in the Orange Creek Basin focuses on monitoring water quality, diagnosing pollution problems, and working to restore water quality and habitats in lakes and wetlands.

This watershed includes Newnans, Orange, and Lochloosa lakes, as well as Paynes Prairie.
Water quality in the three lakes and Paynes Prairie is degraded because of excessive nutrient runoff from surrounding lands.
Once in a lake, excess nitrogen and phosphorus enhance growth of microscopic algae that turn lake water murky green, shading out underwater plants.
Gizzard shad and other bottom-feeding fish thrive and often come to dominate nutrient-enriched lakes, recycling nutrients from the lake bottom, thereby exacerbating poor conditions.
Removal of large numbers of rough fish, or fish not prized for eating, is a restoration tool used around the world.
Water quality in Lakes Apopka and Griffin in central Florida improved during rough fish harvests.
Mass-harvest of shad can reduce recycling of nutrients from the surface of the lake bottom.
Harvested shad are used as bait in crab traps and as food for farmed crayfish.
The District plans to conduct a three-year experimental shad harvest from Newnans Lake starting in March of 2009 to see if reducing the shad abundance helps to improve lake water quality.

The 6-week harvest will be conducted under a permit from the Florida Fish and Wildlife Conservation Commission.

Erich Marzolf, Ph.D., is Technical Program Manager and Jian Di is Environmental Scientist for the District’s Orange Creek Basin SWIM program. A limnologist with 17 years of professional experience, Erich has lived in Gainesville for 14 years. A biological scientist and modeler with 12 years of professional experience, Jian has lived in Gainesville for 16 years.