Conservation of Southeastern Fishes
 

Overview

The Southeastern U.S. has the world's greatest diversity of temperate freshwater fishes. Over half (> 500 species) of North America's entire freshwater fish fauna occurs in the region, and new species continue to be discovered and described. Unfortunately, many species are increasingly threatened because of declining conditions in natural aquatic ecosystems throughout the Southeast. The greatest threats to this fauna arise from environmental perturbations resulting from a rapidly growing human population. The primary threats include: habitat loss and fragmentation; degraded water quality; impoundment of rivers; urbanization; and, nonindigenous species.  Over 30% of southeastern freshwater fishes are currently imperiled, and many of these have become jeopardized within the last two decades. In spite of recent threats to the fauna, relatively few southeastern species have become extinct.

Research at the FISC began in the late 1980's to better understand factors responsible for the decline of Southeastern freshwater fishes.  These studies encompass a broad array of topics, including systematics, zoogeography, life history, ecology, physiology, and population biology of imperiled species.

Ongoing activities by FISC scientists have been instrumental in management decisions, including the survey and listing of species, development of recovery strategies, and regional coordination of faunal and habitat assessments. The FISC works cooperatively with state and federal agencies to protect native aquatic resources in the region.

Program Goals

• To support objectives outlined in the multi-agency "Strategy for the Conservation and Recovery of Southeastern Imperiled Fishes" by conducting sound scientific research on the distribution, status, and ecology of native freshwater fishes.
   
• To assess declines in freshwater fish populations and identify causal factors.
   
• To provide data to natural resource management agencies to aid in the protection and management of native species.

Projects

Status and Ecology of the Okaloosa Darter

Since 1988, FISC scientists have been studying the ecology and population dynamics of the federally endangered Okaloosa Darter (Etheostoma okaloosae). The FISC coauthored the Revised Okaloosa Darter Recovery Plan, a strategic document with the principal goal of recovering this species to a point where it can be upgraded to threatened status or delisted altogether.  The FISC collaborates with Loyola University scientists to quantitatively monitor darter populations at 28 permanent stations using underwater visual surveys.  Eglin Air Force Base, which controls 90% of the watershed area in the range of this species, uses the results of these studies to adaptively manage the landscape.

Aquatic Faunal Surveys of Eglin Air Force Base, Northwestern Florida

This study documents the distribution of fish, mussels, and crayfishes across basins managed by Eglin AFB. Electroshocking boats and backpack shockers are used to collect fishes and crayfishes, while SCUBA diving is employed to hand-collect mussels.  Six distinct aquatic faunal groups have been identified from the alluvial Yellow River to the tannin-stained East Bay River systems.  Water chemistry, geological characteristics, and watershed area are principal factors associated with faunal distributions.

Effects of Suspended Sediment on the Reproductive Success of the Tricolor Shiner

Excessive sedimentation of rivers and creeks has been linked to increased imperilment of the southeastern fish fauna. Obligate benthic spawning fishes have especially decreased in abundance and range size. The tricolor shiner is a crevice-spawning minnow that is widespread in the eastern Mobile River drainage above the Fall Line.  FISC researchers conducted a controlled laboratory experiment to compare the proportion of available eggs spawned and developmental stages of offspring produced under a regime of four different levels of suspended sediment.  This was done in an effort to examine response to sediment in a surrogate species closely related to the federally threatened blue shiner (Cyprinella caerulea).   Although sediment had no effect on the mortality of eggs, both the proportion of eggs spawned and the timing of spawning were significantly affected by increasing levels of suspended sediment.

Conservation of Imperiled Species in the Upper Coosa River System

The upper Coosa River system in Georgia, Alabama, and Tennessee contains 15 at-risk benthic and spring species identified by the U.S. Fish & Wildlife Service as high-priority species in need of current status surveys to determine relative abundance, range limits, and identifiable threats to populations and habitats. The research has several goals: 1) to determine if any of the target species merit further consideration for listing under the Endangered Species Act; 2) to assess spatial relationships of fish distributions to major landscape features such as topography, physiography, surficial geology, and land-use patterns; 3) to determine current status of the nonindigenous and invasive red shiner (Cyprinella lutrensis); and, 4) to characterize the nature and severity of threats to the threatened blue shiner (Cyprinella caerulea) and its habitat in the Conasauga River.

Ecophysiological Studies and Effects of Stressors on Native Species

FISC scientists conduct critical research directed towards elucidating the effects of environmental conditions on aquatic organisms in the context of conservation and evolutionary biology.  The program is focused toward integrating research to better understand core ecological and physiological processes, causal mechanisms, and adaptive responses of aquatic organisms to changing environmental conditions that result from both natural and anthropogenic factors. The research objective is to incorporate ecological and physiological data together with phylogenetic, distributional, life-history, and other biological information that provides a comparative and integrated understanding of faunal change and biodiversity decline. Emphasis is on upland species of the Southern Appalachians, river and estuarine species in the southeastern Coastal Plain, and invasive nonindigenous species as threats to the native fauna.

National Water-Quality Assessment Studies

The FISC provides field assistance, technical expertise, and coordination for rendering accurate taxonomic identifications, establishment of quality assurance/quality control procedures, cataloging and curation of preserved material, and data consistency for the U.S. National Assessment (NAWQA) Program.  In addition, FISC scientists provide direct support for fish sampling and identification in the Mobile River basin study unit. This work includes a pilot study to examine the effects of an urban land-use gradient across small-order stream habitats in the Cahaba and Coosa River valleys.  The gradient study is an integrated project designed to investigate land use patterns and their effects on physical, chemical, and biological indicators of water quality.
 

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Biographies of Southeastern Freshwater Fishes