Future climate impacts on the hydrology of headwater streams in the Amazon River Basin: Implications for migratory goliath catfishes

Abstract

Climate-driven alterations of hydro-meteorological conditions can change river flow regimes and potentially affect the migration behaviour of fishes and the productivity of important fisheries in the Amazon basin, such as those for the continental-scale migratory goliath catfishes (Brachyplatystoma, Pimelodidae). In this study, we investigated hydrologic responses to climate change using a hydrologic model forced with climate inputs, which integrate historical (2001-2010) observations and general circulation model (GCM) projections under the emission scenario Representative Concentration Pathway 8.5. We developed an empirical model to characterize future (2090-2099) climate-change impacts on goliath catfish spawning migrations as a function of river flow depth dynamics at the upstream elevational limit of spawning (250 m) in headwater basins of the Amazon. The model results revealed spatially variable impacts of climate change on the catfish spawning migrations. The Marañón, Ucayali, Juruá, Purus, and Madeira basins had a predicted increase in the annual mean (3-8%) and maximum (1.1-4.9%) spawning migration rate (i.e., the fraction of fish that migrate to the spawning grounds in a day), mainly due to the lengthened rising phase of flow-driven migratory events during wet seasons. The Caquetá-Japurá, Putumayo-Içá, Napo, and Blanco rivers had predicted decreases (3-7%) in the mean migration rate because of decreases in the length of the rising season of flow depth and the frequency of migratory events. The predicted timing of fish spawning migrations (quantified by the temporal centroid of migration rates) was delayed by

Amazon floodplain hydrology and implications for aquatic conservation

“…Understanding how climate changes affect Andean river hydrology is key to understanding responses of pimelodid catfishes, a diverse and economically important group, to environmental changes (Barthem & Goulding, 1997; Barthem et al, 2017). For example, Feng et al (in press) used a hydrological model forced with historical and projected climate data to characterize changes in river flows on the eastern Andean slopes that provide access for pimelodid catfish to spawning grounds. Their results imply that the hydrological conditions may be favourable for catfish movement in the north west but disadvantageous in other regions as the climate changes.…”

Proactively averting the collapse of Amazon fisheries based on three migratory flagship species

“…The migratory life cycle of B . rousseauxii can be at least 11,600 km between the Amazon River estuary and the far western Amazon, including the Andean Piedmont to at least 250 m in elevation [ 8 , 10 , 38 , 40 – 42 ]. The migratory life cycle of B .…”

“…Though upland deforestation and water quality degradation could eventually surpass overfishing, wetland deforestation, and dams as the principal impacts on fisheries, at present these impacts are less limiting ecologically. Climate change is also expected to cause major hydrological changes [e.g., 42 , 82 ]. In addition to overfishing discussed above, here we address dams and wetland deforestation as the two impacts that require immediate mitigation for robust fisheries management.…”

Impact of future climate change on river discharge and groundwater recharge: a case study of Ho Chi Minh City, Vietnam

“…The CF method was used for the reason that it demands less computational resources and is effortless to generate a broad range of climate scenarios from a variety of GCMs (Khoi & Suetsugi 2012). Furthermore, this method has been extensively used in studies on hydrological responses to changing climate (e.g., Ehteram et al 2018;Feng et al 2020;Farzin & Anaraki 2021). In the CF method, monthly CFs are estimated in reliance on differences between future and historical monthly climate variables simulated by a GCM.…”