Ecol Freshw Fish. 2020;00:1–12. wileyonlinelibrary.com/journal/eff | 1 © 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 1 | INTRODUCTION Disentangle the effect of climate on biology of species has been a central goals in ecology, which is particularly relevant in the con- text of global change (McCarty, 2001; Parmesan, 2006). Changes in phenology (timing of life cycle events) have been reported for several groups, from plants to birds (McCarty, 2001). Advanced and prolonged nesting have been described for bird species with climate warming (see references in McCarty, 2001). Similarly, pro- longed fish spawning was observed at lower latitude in a latitu- dinal gradient in southern Europe (Lappalainen & Tarkan, 2007). Received: 7 March 2019 | Revised: 16 September 2019 | Accepted: 15 October 2019 DOI: 10.1111/eff.12518 ORIGINAL ARTICLE Long-term study of the reproductive timing of the Neotropical catfish Iheringichthys labrosus (Lütken, 1874): Influence of temperature and river discharge Nicolás Vidal 1,2 | Franco Teixeira de Mello 2 | Iván González-Bergonzoni 3,4 | Anahí López-Rodríguez 1,2 | Giancarlo Tesitore 2 | Joaquín Pais 3,4 | Samanta Stebniki 2 | Ivana Silva 3,4 | Alejandro D’Anatro 1 1 Departamento de Ecología y Evolución, Facultad de Ciencias, UDELAR, Montevideo, Uruguay 2 Departamento de Ecología y Gestión Ambiental, CURE, Maldonado, UDELAR, Montevideo, Uruguay 3 Departamento del Agua, CENUR Litoral Norte, Paysandú, Uruguay 4 Departamento de Ecología y Biología Evolutiva, MEC, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay Correspondence Nicolás Vidal, Departamento de Ecología y Evolución, Facultad de Ciencias, UDELAR, Montevideo, Uruguay. Email: nvidal@fcien.edu.uy Abstract Unravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temper - ate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence of temperature and river discharge as triggers of Iheringichthys labrosus’ reproduction. We studied the following reproductive variables: gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (K). Females of I. labrosus were examined in a time series of ten years along three sites located in Lower Uruguay River at the beginning (last week of November-first week of December, spring) and by the end of the re- productive period (middle-end of April, autumn). Generalised linear models detected a positive effect of mean winter temperature and site on the spring mature female GSI. Site was significant in addition to the interaction between temperature and site. Moreover, the effect of winter temperature was stronger than water discharge in triggering reproductive timing of I. labrosus, contrary to the model proposed for other species in tropical systems. Additionally, a literature review suggested a latitudinal gradient on reproduction, occurring earlier and prolonged with decreasing latitude (and increasing temperature). In this study, we stated the effect of temperature on the life history in a Neotropical fish using a multifaceted approach, particularly im- portant in the current context of global climate warming. KEYWORDS Iheringichthys labrosus, reproduction, Uruguay River, warming