SI-1543
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Background: Rivers and estuaries along the Atlantic coast support both military installations and populations of the federally endangered shortnose sturgeon (Acipenser brevirostrum). This project will focus on the population in the Ogeechee River system, near Fort Stewart. Potential factors that threaten recovery of this population include: (1) siltation of spawning areas, (2) degraded water quality in summer due to upstream agriculture, urban development, and military land use, (3) atmospheric mercury, (4) saline water introduced through rice canals, and (5) by-catch in the shad fishery. Each of these factors influences one or more lifestages through the following mechanisms: (a) siltation of spawning gravels, (b) methyl mercury toxicity to early lifestages, (c) salinization of freshwater habitat, (d) degraded summer water quality, and (e) harvest. Military land and water management practices influence some of these factors because rivers collect and concentrate the effects of land disturbances, and because installations discharge wastewater. Objective: The goals of this research are to: (1) quantitatively partition the influences on shortnose sturgeon recovery under the control of the military from those that are not, (2) prioritize recovery efforts, and (3) quantify population thresholds. Through modeling efforts, this project aims to quantify the cumulative and separate effects of: (1) siltation, (2) nutrient and carbon inputs to rivers due to military activities and land management, (3) atmospheric mercury, (4) rice canal salt inputs, and (5) by-catch in the shad fishery, on the long-term persistence of the shortnose sturgeon population in the Ogeechee River, and the Canoochee River which drains Fort Stewart, Georgia. Through additional empirical research, this project aims to improve the understanding of stressors affecting blackwater rivers and the fish that populate them. Summary of Process/Technology: Population viability analysis (PVA) provides a scientific basis for assessing cumulative and separate effects through a combination of empirical analysis and modeling. Mechanistic PVA models make it possible to partition the influences of contributing recovery factors, with the goal of prioritizing recovery efforts. A coordinated field and modeling effort will be conducted in order to quantify cumulative effects on the endangered shortnose sturgeon at Fort Stewart. A mechanistic, spatial PVA model will be designed and implemented that links sturgeon population dynamics to land and water uses on- and off-base. These linkages will depend on modeling the physical habitat and developing empirical relationships between the river habitat and individual sturgeon growth, survival, and reproduction. These relationships will be obtained by analyzing existing data and collecting new data to fill critical information gaps. The importance of each sturgeon recovery factor will be estimated by comparing the distributions of population sizes predicted by a series of model simulations where one or more risk factor is removed from the model. |
Benefit: A mechanistic PVA modeling approach will be developed for predicting how on-base and off-base uses of land and water modify the habitat and water quality experienced by a riverine fish. The results will have direct relevance to prioritizing recovery efforts for southern populations of shortnose, Gulf, and Atlantic sturgeon, all of which are species of conservation concern. Accomplishments: This is a FY07 New Start Project. Accomplishments will be listed upon its completion. Contact Information: Lead PI: Dr. Henriette I. Jager Oak Ridge National Laboratory PO Box 2008, Mail Stop 6036 Bethel Valley Road Oak Ridge, TN 37831-6036 E-Mail: jagerhi at ornl.gov Phone: 865/574-8143 Fax: 865/576-3989 |
| REVISED 7/11/2007 | |
