Fidelity, proximity, and climate determine tributary use of spawning flannelmouth sucker in a desert river

Authors: Sophia Bonjour, Keith Gido, Mark McKinstry, Charles Cathcart, Matthew Bogaard

Year: 2021

Abstract

Migration of spawning flannelmouth suckers, Catostomus latipinnis, from mainstem rivers into tributaries has been documented throughout the Colorado River Basin. In the San Juan River basin, McElmo Creek serves as the only perennial tributary without dams or diversions within 10 km of its mouth and annually hosts thousands of spawning flannelmouth sucker. We used nine years of passive integrated transponder (PIT) and radio telemetry data to quantify 1) where spawning fish in this tributary were tagged in the winter, 2) inter-annual variation in the timing of arrival and duration of stay in the tributary and 3) the prevalence of tributary fidelity of migrating fish. Fish PIT tagged in the San Juan River closer to McElmo Creek in December 2020 were more likely to spawn there the following March (50% of fish tagged 5-13 kilometers and 20% of fish tagged 35-42 km from the mouth of McElmo Creek). During wetter years (2017, 2019) fish moved into McElmo Creek earlier (median arrival 25 days earlier) and stayed longer (median residency time 44 vs 20 days). Fish PIT tagged in 2013 and 2014 had an apparent survival of 0.79 and detection probability of 0.67-0.99 from 2014 - 2020 indicating high fidelity and annual return to McElmo Creek. Recognizing patterns and variability in flannelmouth sucker tributary spawning is important for understanding the role of flannelmouth suckers in these systems and how changes in flow patterns may affect them.