Otolith morphometry and microchemistry as habitat markers for juvenileMugil cephalusLinnaeus 1758 in nursery grounds in the Valencian community, Spain

Abstract

Summary The aim of this study was to identify and characterize juvenile Mugil cephalus (flathead grey mullet) habitats in the Valencian community by means of otolith morphometry and microchemistry. Specimens (total length: 250–350 mm) were obtained from October 2011 to March 2012 with gill nets in two protected wetlands: the Parque Nartural de l'Albufera de Valencia (AV) (n = 45), a Mediterranean lake; and the Parque Natural Salinas de Santa Pola (SP) (n = 37), a coastal salt marsh. Otolith shape indices (circularity, rectangularity, aspect ratio, surface occupied by sulcus, ellipticity and form factor) and microchemistry (Sr/Ca and Ba/Ca ratios) were measured and compared as area markers. The chemical composition of the water in both areas was also obtained. Morphometric results showed, by an ANOVA with Bonferroni contrasts, that saccular otoliths from AV individuals had more edge complexity, hence a higher circularity index (p < .001), but that there was less otolith percentage occupied by the sulcus (p < .001). When analyzing the morphometric variables simultaneously, both sites differed significantly (Hotelling's T2 < 0.001). A paired t‐test among sites of the microchemical variables showed that otoliths of AV presented higher values of Ba/Ca ratios and lower Sr/Ca ratios (p < .001). This coincides with water values obtained and could be associated with the low salinity observed in the lake. The opposite pattern was observed in SP, both for otolith and water samples, this being associated with the high‐salinity waters of the area. Results obtained in the present research suggest, by the use of otolith morphometry and microchemistry, that the nursery grounds of juvenile M. cephalus in the Valencian community could be differentiated. Even though habitats could be separated using otolith morphometry, only a few of the studied shape indices were important in area differentiation. Nevertheless, the use of both methodologies simultaneously could be robust habitat markers for this species.

Population structure and habitat connectivity of Genidens genidens (Siluriformes) in tropical and subtropical coasts from Southwestern Atlantic

“…This integrated approach may be an effective tool for further studies of catfish population structure. The ability to differentiate stocks and nursery areas through integrated otolith chemistry and shape analysis has been demonstrated for several Southwestern Atlantic species, such as Odontesthes bonariensis (Avigliano et al, 2014), Prochilodus lineatus (Avigliano et al, 2017b), Mugil liza (Fortunato et al, 2017b), Mugil cephalus (Fortunato et al, 2017a).…”

Morphometric analysis of lapillus otoliths in two estuarine bioindicator catfish (Siluriformes, Ariidae) from a marine protected area in Brazil

“…In this context, some authors have used lapillus otoliths to determine age and growth in populations of ariids that inhabit the Brazilian coast, such as Genidens genidens, Genidens barbus, Netuma barba, and Sciades proops (Reis, 1986;Oliveira and Novelli, 2005;Carvalho, et al, 2014;Freire et al, 2017;Maciel et al, 2018Maciel et al, , 2019. Some studies on otolith morphometrics in ariids have also been performed to aid in species identification (Chen et al, 2008;Vaz-dos-Santos, 2015), differentiation of sexual dimorphism (Maciel et al, 2019), and as an indication of habit use and movement between regions of the species by chemical evaluation (i.e., Ca/Sr, Ca/Ba) in lapillus otoliths (Avigliano et al, 2015(Avigliano et al, , 2020(Avigliano et al, , 2021Fortunato et al, 2017;Condini et al, 2019;Maciel et al, 2020). Finally, lapillus otoliths of C. spixii have been used to compare with those of the species G. genidens (Carvalho et al, 2014), and these structures have been used in assessments of the somatic growth-otolith growth relationship (Azevedo et al, 2019).…”

White mullet Mugil curema population structure from Mexico and Brazil revealed by otolith chemistry

“…There are many precedents on the use of otolith microchemistry for the study of population structure of fish (Macdonald et al ., 2020; Moreira et al ., 2018; Soeth et al ., 2019), even in mugilid species such as M. liza (Callicó Fortunato et al ., 2017b; Lemos et al ., 2017) and M. cephalus (Callicó Fortunato et al ., 2017c). Particularly for M. curema , otoliths have been used to study their habitat use in Brazil (Mai et al ., 2018); the discrimination of phenotypic stocks, age determination and migratory history in Mexico (Ibáñez et al ., 2012, 2017; Ibañez‐Aguirre & Gallardo‐Cabello, 1996); and population identification and recruitment in Venezuela (Avigliano et al ., 2015a; Marin et al ., 2003) applying different techniques like trace elemental ratio analyses and morphometry and microstructure analyses.…”