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Over 10,000 dams impound rivers and streams in the three Southeast Atlantic states. North Carolina has over 5,600 dams and barriers on 17,000 stream miles, many of which are old and obsolete structures. There is an average of one barrier structure every three miles. The state also ranks second in the number of high-hazard dams, which can negatively affect the safety of the citizens of North Carolina and aquatic species. These dams impede movements of many native river resident species, such as Brook Trout and Shoal Bass, but also restrict migrations of marine fish that rely on rivers for various life stages, including Striped Bass, Atlantic Sturgeon, American Shad, American Eels, and river herring. In many cases,...
A. Pervasive disturbances: The most common disturbances based on total stream length in a given region. Top five overall most pervasive disturbances to all stream reaches, regardless of stream size and across all spatial scales (ranked highest first): Impervious surface cover Pasture and hay land use Population density Road density Low intensity urban land use Top three most pervasive disturbances to creeks (<100 km 2 watersheds) across all spatial scales : Impervious surface cover Population density Road density Top three most pervasive disturbances to rivers (>100 km 2 watersheds) across all spatial scales : Pasture and hay land use Upstream dam density Mine density. Top five most pervasive disturbances...
Agriculture was highly influential on the fish habitat assessment of the Pacific Coastal States. One of the broadest areas implicated is the California Central Valley that extends 450 miles from Redding to Bakersfield. This region grows a wide variety of row crops and fruit trees and supports abundant cattle and dairy farms. Another region of very high risk is Willamette Valley in Oregon, where crops such as berries, vegetables, sod, and vineyards are grown. Silviculture, particularly large-scale timber clearcuts, is another significant agricultural practice in this area. Also at high risk are aquatic habitats in eastern Washington between Spokane and Walla Walla, where wheat, hay, potatoes and apples are the dominant...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2015,
Agriculture,
HumanActivity,
PacificCoastRegion,
PacificCoastStates
The Topeka Shiner ( Notropis topeka ) requires prairie streams or oxbows that have good water quality and cool to moderate temperatures. Land practices that increase siltation, such as agricultural use, clear-cut logging, urban development, and intensive grazing, have negatively affected this fish species which is now listed as endangered under the Federal Endangered Species Act. Excessive sedimentation from poorly planned and controlled human development covers fish eggs, reduces instream cover, and fills in gravel areas needed for feeding.
The Sacramento River represents by far the largest population of returning Chinook Salmon (Oncorhynchus tshawytscha). There are four distinct spawning runs of Chinook Salmon; fall, late fall, winter, and spring. Historically, maximum spawning runs in the Central Valley approached 2 million salmon including: 100,000 late-fall fish; 200,000 winter fish; 700,000 spring fish; and 900,000 early fall fish. Current spawning sizes are a fragment of historic numbers and some of the spawning runs are listed stocks under the Federal Endangered Species Act. In 2009, total Chinook Salmon spawning populations were fewer than 69,000 salmon including: 50,000 fall fish; 10,000 late-fall fish; 3,800 spring fish; and 4,700 winter...
Although Alaska has substantial intact habitats, issues quickly appear in areas associated with development. The Arctic Grayling (Thymallus arcticus) requires large intact reaches of river to thrive. Some populations are stressed in developed areas as a result of habitat loss due to poorly designed road crossings that fragment streams along with poorly conducted mining, agricultural, and forestry practices.
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2015,
Alaska,
AlaskaRegion,
FishWithHabitatTrouble
Agriculture is the primary land use in these states. A wide variety of row crops are grown throughout the region and there is also a substantial amount of managed industrial forests. Dominant crops are soybeans and corn in Louisiana, peanuts and cotton in Mississippi and Alabama, and citrus and sugarcane in Florida. Cattle farms are common in Mississippi, Alabama, and Florida. Rice is a major commodity in Louisiana and Mississippi. Aquaculture is also a significant practice in all four states and can alter wetland habitat, water flow patterns, and discharges nutrients into these systems. Phosphate mining (for fertilizer) in wetland areas throughout Florida has interrupted natural water flow and breaks in retention...
Accounting for natural variation Besides influences of human landscape factors on fishes, many “natural” landscape factors also affect species composition and their abundances found in different stream habitats. We incorporated multiple analytical steps that accounted for factors like stream catchment area, elevation, and slope; estimates of groundwater contribution to stream baseflow; and mean annual precipitation and air temperature in stream catchments. Also, because of broad differences in distributions of stream fish species in different-sized streams and across the United States, we developed assessment scores specifically for small and large streams and within nine large ecoregions of the country ( WSA ecoregions),...
Because fish reflect the quality of the habitat where they live, habitat conditions were evaluated by estimating how strongly various human habitat disturbances affect stream fish in all parts of the country. The national datasets used for this assessment included 26 variables that accounted for different human disturbances to aquatic habitats. These included: the quantity of urban, agriculture, and pasture lands in watersheds; major point-sources of water pollution; frequency of dams and road crossings throughout river networks; and intensity of mining activities in watersheds. Five natural landscape variables were also used to account for their potential influences on stream fishes. Because of broad differences...
Table displays Individual disturbance variables that were assembled within four disturbance categories, and summarized
Lake Sturgeon (Acipenser fulvescens) is the largest species (maximum weight between 300-400 lbs.), longest lived (50-year-olds are common but can reach over 100 years in age), and among the slowest maturing species (first reproduction is between 15-25 years old) found in the Great Lakes region. Historically, this species had populations that numbered in the millions basin-wide but had been reduced to remnant populations by 1920 from overharvest; habitat destruction from river channel alteration, landscape scale logging, and pollution from industrialization; and barrier construction. The Lake Sturgeon requires clean rock substrates for spawning and often undertakes long migrations to complete its life history. Although...
Human-caused modifications to surface and ground water systems throughout Hawaii have drastically altered natural hydrologic regimes (a key fish habitat process), which in turn have profoundly limited the distribution and population sizes of native aquatic fauna. Most water for cities comes from wells, although stream water is used in Upper and East Maui. However, smaller communities and agriculture often rely on surface water obtained through diversions. Irrigation systems have been built to support the cultivation of row crops, such as corn, tomatoes, sugar cane, and nut trees. They transfer large volumes of water from natural watercourses and groundwater and into networks of ditches, tunnels, flumes, reservoirs,...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2015,
Hawaii,
HawaiiRegion,
HumanActivity,
ReducedWaterFlows
Corn, soybeans, other row crops, and dairy farms dominate the landscape across southern Minnesota, Wisconsin and Michigan. Most of the agricultural activity in this region came at the expense of the large wetland complexes and woodlots that were found across the landscape in this region.Tile drains have been used extensively throughout the region and have turned streams and wetlands into drainage ditches, devoid of fish habitat. These drainage systems have completely altered stream flow patterns (hydrology), increasing watershed-wide peak discharge events that have destabilized downstream river reaches and decreased baseflows, in these areas. These changes in water flow patterns have created higher bank erosion...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2015,
Agriculture,
HumanActivity,
UpperMidwestRegion,
UpperMidwestStates
Description of Dams and Other Barriers as a Human Activity Affecting Fish Habitat in Mountain States
There are more than 9,800 regulated dams in the Mountain States and 69 percent are in Colorado and Montana. This does not include a large number of dams that are not regulated under dam safety codes, in particular the large number of water withdrawal structures. Dams and irrigation diversion structures provide power and flood control along the rivers of the mountain states, as well as supply water to the farms, ranches, and cities in these states. The reduced flows from water diversions result in less water in the streams for fish, and these altered flows change river habitat by changing sediment and woody debris recruitment and transport, a key factors that control fish habitat that could only be partly examined...
The Shoal Bass (Micropterus cataractae) is one of a number of unique, lesser-known native bass species that have very restricted distributions. Juveniles and adults of this species require riffle and pool habitat with clean gravel substrate for spawning. Although the exact mechanism of population declines for this species has not been proven, the Apalachicola-Chattahoochee-Flint basin where Shoal Bass occur is the second-most impounded basin east of the Mississippi River, with more than 1,400 impoundments. The dams have fragmented and destroyed habitats through inundation, altered water flows, changed temperature regimes, and allowed the establishment of similar competing non-native basses, such as the Spotted...
A. Pervasive disturbances: The most common disturbances based on total stream length in a given region. Top five overall most pervasive disturbances to all stream reaches, regardless of stream size and across all spatial scales (ranked highest first): Population density Impervious surface cover Road length density Pasture and hay land use Low intensity urban land use Top three most pervasive disturbances to creeks (watersheds <100 km 2 in area) across all spatial scales: Population density Impervious surface cover Road length density Top three most pervasive disturbances to rivers (watersheds >100 km 2 in area) across all spatial scales : Pasture and hay land use Crop land use Impervious surface Top...
Mississippi designated the Largemouth Bass as the official State fish in 1974, and it is the State freshwater fish in Florida, Alabama, and Georgia. The Pascagoula River is a unique resource because it is the only nearly completely free flowing (undammed) river in the region. With more than 10 cubic kilometers (2.4 cu mi) of water flowing per year into the Gulf of Mexico, it is the largest (by volume) undammed river in the contiguous 48 States. In fact, it is also the largest undammed river in the warm, humid region (Köppen climate classification zone), with southeastern Brazil claiming the second and third largest rivers in the climate zone. As a result, there continues to be a concerted effort to prevent dam construction...
Cattle and sheep ranching are common in Southern Plains States. Areas of very high risk of habitat degradation in eastern portions of this region correspond to areas characterized as pasture. Rain and snow melt carry nutrient-rich animal waste to streams and rivers and when livestock drink from local streams they trample the stream banks and cause excessive sedimentation in the streams. Sedimentation, caused by many forms of human activity, has affected many rivers and reservoirs of the Southern Plains and work is underway in some areas to rehabilitate reservoirs affected by sedimentation. For example, a large scale project to remove seven million cubic yards of sediment from Lake Wichita, Texas is underway. Rehabilitating...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2015,
HumanActivity,
Pasture,
SouthernPlainsRegion,
SouthernPlainsStates
While the overall assessment indicated that fish habitat in this region is some of the most threatened in the United States, some of the key fish habitat forming processes, such as water flow (hydrology) and grazing intensity, could not be fully included in this assessment as there are no national coverages for all of the supporting data needed to properly examine these processes. As a result, habitat condition (quality) has likely been overestimated for some systems in this region and the risk of degradation is likely higher than estimated. It is expected that future national assessments will include information on more of the key habitat processes as resources and data are available. The results from this assessment...
The National Estuary Assessment combined landscape and estuary measurements of habitat stressors to produce an estimate of the risk of current habitat degradation for each estuary. The assessment was built on the assumption that both anthropogenic (human caused) activities within estuarine watersheds and local factors affect estuary habitats. This assessment provides an updated outlook of the estuary condition that was presented in 2010 using the same general approach. However, results from the 2010 and 2015 National Estuary Assessments should not be viewed as an indication of change for several reasons. First, the assessment estimates current habitat stress relative to levels found in other estuaries within the...
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