Diets of invasive channel catfish are subsidized by invasive riparian trees

Abstract Russian olive ( Elaeagnus angustifolia ) is an invasive, fruit‐bearing riparian tree that dominates zones of the San Juan River in southwestern United States. Previous research this river suggests fruit common diets invasive channel catfish Ictalurus punctatus ), but its energetic importance unknown (i.e. critical for fitness vs. incidental consumption). We assessed consumption bimonthly 1 year, hypothesizing would be greatest during periods high availability and low benthic aquatic invertebrate availability. found consumed throughout year comprised up to 44% total stomach contents by mass, with peaks spring fall. Regression models revealed presence mass stomachs were positively associated length, a significant interaction between water temperature discharge. Catfish more likely consume higher flows, regardless at discharge temperature. Contrary our hypothesis, neither nor diets. Nutrition analysis indicated alone was low‐quality diet item has potential provide reliable energy source. used seasonal data estimate contribution populations using bioenergetic model, which estimated accounted 35.6% (Joules) satisfied 38% their metabolic demand. Our results suggest subsidy River. However, needed determine indirect effects on native fishes ecosystem function.