Otolith morphometry and microchemistry as habitat markers for juvenile Mugil cephalus Linnaeus 1758 in nursery grounds in the Valencian community, Spain

CALLICÓ FORTUNATO, ROBERTA; VOLPEDO, ALEJANDRA; BENEDITO DURA, VICENT

Journal of Applied Ichthyology

Wiley Online Library

Año: 2016

The aim of this study was to identify and characterize juvenile habitats of Mugil cephalus in the Valencian Community by means of otolith morphometry and microchemistry. Specimens (total length: 250 ? 350 mm) were obtained with gill nets in two protected wetlands (October 2011-March 2012): 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 markers of area. Water chemical composition 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 higher circularity index (p < 0.001); but less percentage of otolith occupied by the sulcus (p < 0.001). 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 < 0.001). This coincides with the obtained water values and could be associated to the low salinity observed in this lake. The opposite pattern was observed in SP, both for otolith and water samples; being this associated to the high-salinity waters of this area. Results obtained in the present research suggest that by the use of otolith morphometry and microchemistry nursery grounds of juvenile Mugil 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 as markers of habitat for this species.