Recruitment of juvenile fishes into a small temperate choked lagoon (Argentina) and the influence of environmental factors during the process.

BRUNO D.; COUSSEAU M.B.; DIAZ DE ASTARLOA J.M.; ACHA E.M.

SCIENTIA MARINA

INST CIENCIAS MAR BARCELONA

Lugar: Barcelona; Año: 2015 vol. 71 p. 43 - 55

0214-8358

Juvenile fishes were sampled every 15 days from September 2009 to April 2010 along the marine-estuarine gradient (i.e. Surf zone, Estuary, a freshwater stream) of the Mar Chiquita lagoon (Argentina). The temporal variations of juvenile assemblages during spring-summer and the environmental variables related to the spatial and temporal patterns were analyzed. Four groups of sampling stations were defined indicating differences in fish composition among zones during the Spring-Early Summer period (Groups I to III) while the composition of juvenile fishes was homogeneous along the marine-estuarine gradient during the Late summer-Early autumn period (Group IV). Platanichthys platana and Ramnogaster arcuata (Group A) and Odontesthes argentinensis and Brevoortia aurea (Group B) contributed most to the temporal differences observed. The three first species reached this estuarine system during Spring months, although with lower abundances in relation to Early Summer months, while B. aurea was dominant during Late Summer-Early Autumn months denoting distinct recruitment periods to the lagoon by these species. After factoring out shared spatial-temporal-environmental factors variation (4.43%), the canonical correspondence analysis (CCA) showed that temporal components had an almost 5-fold greater contribution (15.15%) than spatial components (2.85%) and almost twice than the pure environmental factors (8.11%) in explaining the variation in abundance of the juvenile fishes. From the significant environmental variables incorporated in the CCA, wind direction contributed most than water temperature, salinity or transparency in explaining data variability. Indeed, most species were related to ?onshore winds? and therefore, the importance of wind on the successful recruitment of juveniles into this shallow and micro-tidal estuary is discussed.