Science of the Total Environment 752 (2021) 141864 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv Impact of Chaitén Volcano ashfall on native and exotic fish recovery, recolonization, and abundance Cecilia Yanina Di Prinzio a,b,⁎, Brooke Penaluna c, Marta Gladys Grech a,b, Luz María Manzo a, María Laura Miserendino a,b, Ricardo Casaux a a Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina b Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco, Esquel, Chubut, Argentina c U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, United States of America HIGHLIGHTS GRAPHICAL ABSTRACT • Fish recolonization is ongoing taking 4 days to 9 months after the eruption. • Fish abundances changed over the 21- month study period post-volcanic erup- tion. • Introduced Rainbow Trout was the pio- neer recolonizer. • Catfish were the slowest to recolonize albeit suffered lower impact from the eruption. article info abstract Article history: The effects of volcanic disturbance on aquatic communities and their recovery are poorly studied. To fill this gap, Received 15 May 2020 we explored the effects on fish communities in rivers in Argentina of the 2008 eruption of Chaitén Volcano in Received in revised form 27 July 2020 southern Chile (42.8° lat. S). The eruption produced volcanic plumes of ash that persisted in the atmosphere Accepted 19 August 2020 for several months. Borne on westerly winds, deposits of tephra crossed the Andes Mountains, reaching the At- Available online 21 August 2020 lantic coast (Argentina). We compared the pre- and post-eruption abundances of a native catfish Hatcheria Editor: Sergi Sabater macraei, and two introduced trout from rivers covered by the volcanic plumes (Argentina) using Before-After- Control-Impact analysis to explore fish recovery. Total suspended solids from volcanic ashfall, macroinvertebrate Keywords: abundance and richness, and species ecological attributes influenced the spatial arrangement of fish in rivers. Volcanic disturbance Twenty-one months after the eruption, Rainbow Trout, Oncorhynchus mykiss, had not returned to pre-eruption Fish repopulation abundances in the sampled rivers, and only four rivers had regained pre-eruption species composition, suggest- Disturbance ing that disturbance is still ongoing. The abundance of introduced fishes was strongly, negatively correlated with Ash deposition TSS, suggesting that ashfall affected these fish probably by clogging and abrasion of the gills. Fish recolonized pre- Tephra fall viously occupied habitats 4 days to 9 months after the disturbance. Hatcheria macraei was the slowest to recolo- nize, whereas O. mykiss were the pioneer fish in 4 rivers following the eruption and recolonized all 5 rivers where they were present prior to the eruption. In one river, the catfish and the Brown Trout, Salmo trutta, were still ab- sent 21 months post-eruption, potentially owing to the lack of riparian cover that would have deflected the entry of ash. Rainbow Trout suffered significant declines in abundance, whereas Brown Trout and catfish generally did not, owing to their ecological attributes. Total fish abundance was negatively correlated with ash thickness, but positively related to prey availability. © 2020 Elsevier B.V. All rights reserved. ⁎ Corresponding author at: Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina. E-mail address: [email protected] (C.Y. Di Prinzio). https://doi.org/10.1016/j.scitotenv.2020.141864 0048-9697/© 2020 Elsevier B.V. All rights reserved. 2 C.Y. Di Prinzio et al. / Science of the Total Environment 752 (2021) 141864 1. Introduction assessed (Inbar et al., 1995). The 2011 eruption of Puyehue-Cordón Caulle in Chile was another opportunity to investigate the role of volca- On 2 May 2008, the Chaitén Volcano in southern Chile released an nic eruptions in shaping fish responses. Although declines in introduced explosive plume of ash and steam into the atmosphere, coating a salmonid abundances post-eruption were linked to changes in habitat broad area across southern South America with ash without warning. and macroinvertebrate assemblages, with decreasing effect with in- Strong eruptive activity continued over the next week, and the ash col- creasing distance from the eruption site, the eruption impact on native umn reached 30 km high at its peak, but gradually diminished over the fishes was not studied (Lallement et al., 2016). A better understanding next several months (Watt et al., 2009). The average ash thickness de- of the effects of volcanic ashfall on fishes of South America is needed, es- posited across affected regions of Argentina was 5–10 cm (Watt et al., pecially for native fishes. 2009). More generally, explosive volcanic eruptions are recognized as The native ichthyofauna of the Patagonia is characterized by a low unpredictable natural disturbances that may result in profound biolog- species richness (Ringuelet, 1975; Baigún and Ferriz, 2003; Soto et al., ical and environmental responses depending on the magnitude, compo- 2006). Since the early 1900s, the Patagonia region of Argentina has un- sition of the ejected material, particle size, distance from the explosion, dergone continuous stocking of introduced salmonids, mostly for recre- and duration of the event (Annen and Wagner, 2003; Martin et al., ational purposes (Pascual et al., 2007) resulting in the dominance and 2009; Mather, 2015). Volcanic processes involved in eruptions are widespread distribution of trout, including Rainbow Trout Oncorhyn- highly variable in their potential to disturb ecosystems, and often lesser chus mykiss, Brown Trout Salmo trutta and Brook Trout Salvelinus impacts can be found when fine volcanic ash and lighter particles are fontinalis (Pascual et al., 2002; Arismendi et al., 2019). Consequently, dispersed across broader areas (Arendt et al., 1999; Annen and native fishes currently face continued pressure by invasive salmonids, Wagner, 2003; Martin et al., 2009; Ruggieri et al., 2012). as reflected by the declining numbers in native biota (Macchi et al., Volcanic eruptions lead to a wide range of new environmental condi- 1999; Pascual et al., 2002; Lattuca et al., 2008; among others). Bello tions, as well as a broad spectrum of biotic responses at different scales and Úbeda (1998) estimated that 60% of the native Patagonian fish spe- (Turner et al., 1997). Many responses can benefit the spread of recover- cies have been designated as “threatened”, with some endemic fishes ing biota, but an existing population or community may be extirpated by also regarded as “rare” (López et al., 2003). severe disturbance (del Moral, 1981). For example, the May 1980 erup- Here, we provide baseline information on the responses of native tion of Mount St. Helens in southwestern Washington state, USA, caused and introduced fishes to ashfall from the Chaitén Volcano eruption by a dramatic decrease in terrestrial insect populations (Edwards and comparing pre-eruption and post-eruption data across rivers with a Schwartz, 1981)andmodified the dominant taxa in water bodies closest gradient of ashfall influence. We hypothesized that greater thickness to the blast zone (Anderson and Wisseman, 1987; Edwards and Sugg, of volcanic ash in rivers would have stronger impacts on fish communi- 2005). Chironomid assemblages changed in response to tephra deposi- ties. For example, the increase in total suspended solids might clog fish tion in Lake Galletué, Chile likely from Llaima Volcano in 1957, with gills and suffocate them, or cause abrasion. Both native and exotic fish the replacement of Ablabesmyia by Parakiefferiella (Urrutia et al., 2007). predate on aquatic macroinvertebrates (Di Prinzio and Casaux, 2012; Changes in the percentage of collector-gatherer invertebrates in Arismendi et al., 2012), and, consequently, we anticipated that changes Tongariro River, New Zealand, following a series of eruptions of Mount in available prey would reduce fish feeding and lower fish condition, as Ruapehu in 1995–1996 led to a deterioration in water quality and reported in Miserendino et al. (2012). We also anticipated differences in changes to food webs (Collier et al., 2002). The 2011 eruption of the fish responses following the eruption, owing to species´ ecological attri- Puyehue-Cordón Caulle complex, Chile led to the decline of Ephemerop- butes. For example, the native catfish Hatcheria macraei occupies ben- tera, Plecoptera and Trichoptera (EPT) densities, mainly in rivers closer thic habitats, S. trutta use the full water column, but tend to use pools, to the eruption site (Lallement et al., 2014). In response to the 2008 whereas O. mykiss uses the entire water column and many habitat Chaitén explosion, there was a steep decrease in macroinvertebrate den- types (McIntosh, 2000; López et al., 2003; Casalinuovo et al., 2017). Re- sity and richness in rivers of Argentina, with small systems being more sults of this work will help inform management decisions on whether severely affected than larger ones (Miserendino et al., 2012). restocking actions are necessary to accelerate the recovery of fishes fol- Fish responses to volcanic eruptions vary depending on the severity lowing disturbance. of volcanic processes they experience and proximity of the volcano, with the most