Dynamics of early life‐history stages of fish along an estuarine gradient

Abstract

This study aimed to identify the spatial and temporal patterns of composition and distribution of early life‐history stages of fish along an estuarine gradient. Samples were collected quarterly between April 2010 and January 2011 using conical‐cylindrical plankton nets in the Vaza Barris estuarine river system (NE Brazil). A total of 38,781 fish eggs and 3,526 larvae, representing 20 families and 42 taxa, were caught. The most abundant larval taxa were Microgobius meeki, Ctenogobius gr. smaragdus/boleosoma, Gobionellus oceanicus, Ctenogobius gr. stigmaticus/saepepallens/shufeldti, Bairdiella ronchus, Achirus sp., Trinectes sp., Stellifer rastrifer and S. stellifer, accounting together for 34.5% of the total catch. Ichthyoplankton distributions were characterized by high seasonal and spatial variability mainly attributed to the environmental characteristics of the estuary. Overall, lower estuarine region served as important accumulation areas for ichthyoplankton, concentrating the greatest diversity and abundance. Salinity gradient, water temperature, and inorganic nutrients were the main variables that affected the larval fish assemblages, presumably influencing spawning, development and survival of individuals or through their effect on food supply. Moreover, this study reinforced the concept that hydrological variations may have a strong influence on estuarine species retention and marine species immigration. Finally, this study highlights the importance of estuaries for the growth and maintenance of stocks of fish species, and the development of strategies to protect these habitats is of utmost relevance.

Does environmental heterogeneity explain β diversity of estuarine fish assemblages? Example from a tropical estuary under the influence of a semiarid climate, Brazil

“…This difference is most observed in the rainy season due to increases in the influx of young-of-the-years in tropical estuaries related to recruitment success [ 88 ]. It is not surprising that small juveniles are recruiting into suitable habitat influenced by decreasing salinity and increase of turbidity during the rainy season in tropical estuaries [ 1 , 89 ]. Such factors are known to have a positive impact on growth rates of fishes, as well as contributing to the increases in food resources and shelter from predators in shallow waters [ 89 – 91 ].…”

“…It is not surprising that small juveniles are recruiting into suitable habitat influenced by decreasing salinity and increase of turbidity during the rainy season in tropical estuaries [ 1 , 89 ]. Such factors are known to have a positive impact on growth rates of fishes, as well as contributing to the increases in food resources and shelter from predators in shallow waters [ 89 – 91 ]. Moreover, during the rainy season juvenile stenohaline species, which tolerate a narrow range of salinity, occurred in higher abundance principally in lower zones related to more stable conditions, and this is likely the result of the proximity of this zone to the ocean and the higher tidal influence.…”

Ficha de Ctenogobius smaragdus

“…No Brasil, a espécie foi registrada no Amapá, Pará, Maranhão, Piauí, Ceará Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina e Rio Grande do Sul (Araújo et al, 2000;Chaves & Vendel, 2001;Cheffe et al, 2010;Paiva & Araújo, 2010;Reis-Filho et al, 2010;Spach et al, 2010;Menezes, 2011;Sarmento-Soares et al, 2012;Oliveira & Pessanha, 2014;Garcia-Júnior et al, 2015;Marceniuk et al, 2017;Mincarone et al, 2017;Brito et al, 2019;Santos & Severi, 2019).…”

Spring Ichthyoplankton Assemblage Structure in the Yangtze Estuary Under Environmental Factors

“…The other factors, such as pH, D, COD, DO, TN, and SPM, had no significant effect on ichthyoplankton assemblage structure. Temperature has a significant and direct effect on fish reproduction, physiology, growth, and behavior (Sabates et al, 2006;Santos and Severi, 2019), which is very important for the abundance and spatial distribution of ichthyoplankton (Bruno et al, 2014;Chermahini et al, 2021). Estuaries are generally shallow, with large temperature changes, and diurnal and seasonal changes, therefore estuarine species adapted to a wide temperature range often dominate (Yang et al, 2006).…”