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State-wide data on fish populations were limited in Alaska for use in this assessment, as was a detailed spatial (mapping) framework that fully characterizes watersheds throughout the state at the time this assessment was conducted. Because of these factors, we modified our assessment methods to account for these limitations. Twenty-one landscape disturbance variables were assembled from medium-sized watersheds throughout the state (i.e., 12-digit hydrologic unit code watersheds). Variables were then assigned to one of six categories based on their disturbances to stream habitats. Categories include: urban land use, agricultural land use, point source pollution and water quality, barriers to fish movement, human...
Estuaries are the coastal areas where rivers meet the ocean. These areas provide critically important habitat to many fish and shellfish species, and support a variety of important activities (e.g. fishing, shipping, recreation, etc.). These areas, as the transition zone between the land and the sea, are also at high risk for negative effects from human activities including pollution, habitat conversion and loss, and changes to water flows. Understanding how human activities are affecting estuary habitats is important so resource managers can better manage these impacts, and ultimately, sustain estuaries and the fish populations that they support. To analyze estuary condition, a cumulative disturbance index was...
This ScienceBase item provides the queries and code that identifies components and organization of the 'How to Read This Report' chapter for the Inland Stream Assessment for the Conterminous United States.
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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...
The Regional Estuary Assessment for the northern Gulf of Mexico represents an effort to develop, test, and implement a new assessment methodology for marine habitats that improves the analytical basis for identifying impacts to estuarine fish habitats. This new regional assessment approach offers several advantages: Incorporates information on fish/shellfish presence/absence from over 70,000 sampling events collected over two decades, so we can better relate fish habitat condition to natural and anthropogenic variables. Better accounts for the high amounts of natural variation found in the marine environment, which can affect the susceptibility of individual estuaries. Allows us to take advantage of regional datasets...
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This report updates and revises the 2010 “ Status of Fish Habitats in the United States” that summarized initial results of a comprehensive national assessment of aquatic habitats at an unprecedented scale and level of detail. This 2015 report provides even greater detail and improves our knowledge of the condition of fish habitat in the United States. The 2010 inland streams assessment characterized fish habitat condition using stream fish data from more than 26,000 stream reaches, while the 2015 assessment was based on fish data from more than 39,000 stream reaches nationally. To increase accuracy, the 2015 inland stream assessment incorporated 12 additional human disturbance variables into the fish analysis when...


    map background search result map search result map Generalized Methodology for Stream Assessments of Alaska and Hawaii Generalized Methodology for Stream Assessments of Alaska and Hawaii