Water and otolith chemistry: implications for discerning estuarine nursery habitat use of a juvenile flatfish

Variations in otolith elemental composition are widely used to reconstruct fish movements. However, reconstructing habitat use and environmental histories of fishes within estuaries is still a major challenge due to the dynamic nature of these coastal environments. In this study, we performed a laboratory experiment to investigate the effects of variations in salinity (three levels; 5, 18, 30) and temperature (two levels; 16, 21 C) on the otolith elemental composition (Mg:Ca, Mn:Ca, Sr:Ca, Ba:Ca) of juvenile Senegalese sole Solea senegalensis. Temperature and salinity treatments mirrored the natural conditions of the estuarine habitats occupied by juvenile Senegalese sole, thereby providing information on the applicability of otolith microchemistry to reconstruct habitat use patterns within estuarine nurseries, where individual fish move across complex salinity and temperature gradients. While Sr:Ca and Ba:Ca in otoliths were both positively related to salinity, no temperature effect was observed. Partition coefficients, proxies for element incorporation rates increased with increasing salinity for Sr (DSr) and Ba (DBa). In contrast, salinity and temperature had little influence on otolith Mn:Ca and Mg:Ca, supporting physiological control on the incorporation of these elements. Our results are a stepping stone for the interpretation of otolith chemical profiles for fish collected in their natural habitats and contribute to better understanding the processes involved in otolith element incorporation.

Description

FUNDING This research was supported by the Portuguese Foundation for Science and Technology (FCT, I.P.) via a postdoctoral grant to PR-S (SFRH/BPD/95784/2013), a Ph.D. grant to AV (SFRH/BD/137862/2018), and researcher contracts to ST (DL57/2016/CP1479/CT0022), VF (DL57/2016/CP1479/CT0024), FM, and AP, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. FCT, I.P. also provided support through the research project “Mytag– Integrating natural and artificial tags to reconstruct fish migrations and ontogenetic niche shifts” (PTDC/MAR-EST/2098/2014), under the Project 9471– Reforçar a Investigação, o Desenvolvimento Tecnológico e a Inovação (Projeto 9471-RIDTI) and subsidized by the European Regional Development Fund (FEDER, POCI-01-0145-FEDER-016787), the Centre for Functional Ecology Strategic Project (UID/BIA/04004/2019) within the PT2020 Partnership Agreement and COMPETE 2020, and the Marine and Environmental Sciences Centre Strategic Project (UID/MAR/04292/2019). Financial support was also provided by FEDER through the project ReNATURE– Valorization of the Natural Endogenous Resources of the Centro Region (Centro 2020, Centro-01-765-0145-FEDER-000007).

Keywords

Connectivity Flatfish Nursery areas Estuaries Migrations Otoliths

URI

http://hdl.handle.net/10400.8/5094

Citation

Martinho F, Pina B, Nunes M, Vasconcelos RP, Fonseca VF, Crespo D, Primo AL, Vaz A, Pardal MA, Gillanders BM, Tanner SE and Reis-Santos P (2020) Water and Otolith Chemistry: Implications for Discerning Estuarine Nursery Habitat Use of a Juvenile Flatfish. Front. Mar. Sci. 7:347. DOI: 10.3389/fmars.2020.00347