A National Assessment of Stressors to Estuarine Fish Habitats in the Contiguous USA


Correigh M. Greene; Kristan Blackhart; Joe Nohner;
Allison Candelmo; David Moe Nelson

Journal or Book Title: Estuaries and Coasts

Keywords: Estuary; Habitat assessment; River flow; Pollution; Eutrophication; Land cover

Volume/Issue: Online

Year Published: 2014


Estuaries provide vital habitat to a wide variety of
fish species, so understanding how human activities impact
estuarine habitats has important implications for management
and conservation of fish stocks. We used nationwide datasets
on anthropogenic disturbance to perform a quantitative assessment
of habitat stressors in US estuaries. Habitat stressors were
characterized by four categories of indicator datasets: (1) land
cover/land use, (2) alteration of river flows, (3) pollution
sources, and (4) eutrophication. These datasets were combined
using a multiscale hierarchical spatial framework to provide a
composite stressor index for 196 estuaries throughout the contiguous
USA. Investigation of indicator patterns among 13
defined USA coastal subregions revealed clear differences
across the USA attributable to both natural variation as well
as differences in anthropogenic activities. We compared the
mean composite scores for each subregion and found the lowest
stressor index scores in the Downeast Maine and the Oregon
Coast subregions. Subregions with the highest stressor index
scores were the Southern California Bight (due to land cover
changes, river flow alteration, and pollution) and Mid-Atlantic
Bight (due to land cover changes, pollution, and eutrophication).
Inland-based measures of pollutants, river flow, and land
use all showed strong correlations with eutrophication measured
within estuaries. Our approach provides an indicatorbased
assessment for a larger number of estuaries than has been
possible in previous assessments, and in the case of river flow,
for variables which previously have not been evaluated at a
broad spatial scale. The results of this assessment can be
applied to help prioritize watershed and estuarine restoration
and protection across the contiguous USA.

DOI: 10.1007/s12237-014-9855-9

Type of Publication: Journal Article

Publisher: Coastal and Estuarine Research Federation