FACTORS INFLUENCING GROWTH RATE OF FLANNELMOUTH SUCKERS
IN THE GRAND CANYON COLORADO RIVER
Flannelmouth Sucker Growth and Abundance, United States Geological Survey and Northern Arizona University
The flannelmouth sucker (Catostomus latipinnis) (hereafter FMS) is currently the most abundant native fish in the Grand Canyon reaches of the Colorado River, but during the 1990’s, the population was in such low numbers that the species was on the verge of being listed on the Endangered Species Act. However, beginning in the late 1990’s, the species population has increased dramatically. Currently the FMS makes up a significant portion of the fish biomass within the Grand Canyon, but because it has such a stable population, limited research has been conducted to assess its population stability, growth, diet, and migration. Further, the source of energy for this fish biomass is currently unknown for all fish species within the Grand Canyon because the Canyon has such a limitation of food inputs and availability.
In this study, to help understand how FMS have increased over the past two decades, I will explore how the growth rates of individual fish appear to vary over space and time, and test whether this can be explained by available data on temperature and stream metabolism. I propose to build a model using FMS location data to compare primary productivity sources (what food is available in the river) in the canyon with FMS growth throughout time and space. Using an existing 20-year mark-recapture dataset on flannelmouth sucker distribution and size in the Grand Canyon and georeferenced data on primary productivity sources in the canyon, I will create a model to show growth rate and identify the most important factors influencing growth of FMS.
The flannelmouth sucker (Catostomus latipinnis) (hereafter FMS) is currently the most abundant native fish in the Grand Canyon reaches of the Colorado River, but during the 1990’s, the population was in such low numbers that the species was on the verge of being listed on the Endangered Species Act. However, beginning in the late 1990’s, the species population has increased dramatically. Currently the FMS makes up a significant portion of the fish biomass within the Grand Canyon, but because it has such a stable population, limited research has been conducted to assess its population stability, growth, diet, and migration. Further, the source of energy for this fish biomass is currently unknown for all fish species within the Grand Canyon because the Canyon has such a limitation of food inputs and availability.
In this study, to help understand how FMS have increased over the past two decades, I will explore how the growth rates of individual fish appear to vary over space and time, and test whether this can be explained by available data on temperature and stream metabolism. I propose to build a model using FMS location data to compare primary productivity sources (what food is available in the river) in the canyon with FMS growth throughout time and space. Using an existing 20-year mark-recapture dataset on flannelmouth sucker distribution and size in the Grand Canyon and georeferenced data on primary productivity sources in the canyon, I will create a model to show growth rate and identify the most important factors influencing growth of FMS.
Links to my writing about
the grand canyon colorado river system
Impacts of river policy on flannelmouth suckers
and other native fish in the grand canyon
An illustration of the habitat continuum created by Glen Canyon dam and tributary river inputs in the Colorado River in the Grand Canyon. Tributary inputs make water warmer farther from Glen Canyon Dam, and a drought in the past 20 years has led to warming of water releases from Glen Canyon Dam, as well as warmer water inputs into the system from tributaries due to increased solar insolation, lower precipitation, and warmer air temperatures. In this proposal, I hypothesize that warmer temperatures lead to increased growth in FMS.
