Fish assemblages in a small temperate estuary on the Argentinian coast: spatial variation, environmental influence and relevance as nursery area

Abstract

The effects of different environmental variables on the fish community structure were evaluated in a small temperate estuary. The biological and environmental data were collected bimonthly between 2007 and 2009 along the main estuarine axis. Multivariate analyses were applied (CLUSTER, SIMPER, CCA) to determine the spatial structure of fish community and to estimate the environmental influence on it. A total of 48 species of "teleost" fishes were observed, with the families Characidae and Sciaenidae presenting the largest number of species, 90% of the catches being juveniles. The fish community was overwhelmingly dominated by one species (Micropogonias furnieri, 88.9%), and only four species contributed more than 1% of total catch (Odontesthes argentinensis5.4%, Brevoortia aurea 1.1%, Paralonchurus brasiliensis 1.1%, and Mugil platanus 1.0%). Estuarine and freshwater stragglers dominated in number of species, followed by freshwater migrants and marine migrants. Three areas with different fish assemblages, with distinctive species and functional guilds, were defined along the main axis. The occurrence and spatial spread of these areas were linked to spatial variation in salinity, which was consistently influenced by discharge from the Río de la Plata and local precipitation. The results highlight the importance of shallow environments as nursery areas and permit emphasis on their susceptibility to environmental changes.

Fish fauna from the estuaries of Ceará state, Brazil: a checklist in support of conservation of the Brazilian semiarid coast

“…A similar predominance of marine fishes may be observed in other estuaries from Northeastern to Southern Brazil (Vasconcelos-Filho and Oliveira 1999;Paiva et al 2009;Reis-Filho et al 2010;Vilar et al 2011;Passos et al 2013), indicating the importance of estuary environments for the maintenance of marine species that use estuaries for reproduction, feeding, growth, and shelter (Elliott et al 2007). In our survey only 16 species (~13%) could be considered estuarine residents capable of completing their life cycle within this ecosystem (Paiva et al 2009;Reis-Filho et al 2010;Mai and Vieira 2013;Marceniuk et al 2017b;Favero et al 2019) 2014), (16.4%), but in southern regions of the country the percentage of resident species is higher (23-35%) (Reis-Filho et al 2010;Hoeinghaus et al 2011;Vilar et al 2011;Passos et al 2013;Pichler et al 2015;Solari et al 2015). Future studies are needed to prove this possible pattern; however, this pattern may be the result of different sampling methodologies or species guild classifications.…”

Fish diversity in the Río de la Plata and adjacent waters: an overview of environmental influences on its spatial and temporal structure

“…), among others. The high presence of freshwater species (straggler 23·5% and migrants 4·2%) occurs in shallow waters or tributaries (Acuña Plavan et al ., ; Solari et al ., ). In deeper waters freshwater species are occasionally observed and their presence is related to low salinity spread by the high freshwater discharge or to natural processes of species biology [ Parapimelodus valenciennesis (Kroyer 1874), Leporinus obstusidens (Valenciennes 1837) and Luciopimelodus pati (Valenciennes 1840); Jaureguizar et al ., )].…”

“…(c)], where salinity has a stronger influence than temperature (Jaureguizar et al ., ; Vögler et al ., ; Cortés et al ., ). As observed in other coastal systems including estuaries and bays, the selection of inshore waters by neonates and juveniles (RdP: M. furnieri, Jaureguizar et al ., ; Solari et al ., ; coastal shelf ecosystem: M. schmitti , Cortés et al ., ; S. guggenheim , Colonello et al ., ; Vögler et al ., ; C. guatucupa, Jaureguizar et al ., ; P. brasiliensis, C.A. Barreto, unpubl.…”

Inter-estuarine and temporal patterns of the fish assemblage of subtropical subestuaries along the Río de la Plata coast (Uruguay)

“…Considering the relevance of estuarine ecosystems, the fish fauna from the Río de la Plata estuary (RdlP), as well as, of the coastal estuaries along the UruguayanArgentinian coast has been previously studied (LAGOS, 2003;JAUREGUIZAR et al, 2004JAUREGUIZAR et al, , 2016ACUÑA PLAVAN et al, 2010;LORENZO et al, 2011;GURDEK et al, 2011SOLARI et al, 2015;. The RdlP is one of the largest estuaries worldwide, connected permanently to the Atlantic Ocean.…”