Freshwater ecosystems are among the

Freshwater ecosystems are among the most imperiled on Earth
(Richter et al. 1997; Strayer and Dudgeon 2010), with extinction rates
of freshwater fauna higher than for many other ecosystems and
vastly exceeding historic background rates (Leidy and Moyle 1997;
Harrison and Stiassny 1999; Ricciardi and Rasmussen 1999). Freshwater
is vital to humans, and clean water is rapidly becoming a limiting
resource for many societies (Vörösmarty et al. 2010). The greatest
threat to freshwater ecosystems is the loss or alteration of freshwater
habitats through human development (e.g., Dudgeon et al. 2006), yet
our societies and economy depend directly on the services provided
by healthy freshwater ecosystems (Postel and Carpenter 1997). These
services include provisioning of clean water and food, regulation of
climate, flow regimes, and pollution, support for nutrient cycling,
and cultural services such as recreation, tourism, and spiritual benefits
(Vörösmarty et al. 2005). Fishes in particular provide many services
including food, linkage of ecosystems through migrations and
food-web contributions, acting as indicators of ecosystem stress, and
providing social value through recreation and aesthetic values
(Holmlund and Hammer 1999). Most ecosystem services of fishes are
supported by a diverse fauna, not by merely the few species directly
favoured by humans. Humans live side-by-side with fishes and other
aquatic organisms in watersheds, and we derive our quality of life
from the health of these ecosystems (Limburg et al. 2011).