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

CALLICO FORTUNATO, R; V. BENEDITO DURA ; A. VOLPEDO

JOURNAL OF APPLIED ICHTHYOLOGY-ZEITSCHRIFT FUR ANGEWANDTE ICHTHYOLOGIE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 33 p. 162 - 167

0175-8659

The aim of this study was to identify and characterize juvenile Mugil cephalus (flatheadgrey mullet) habitats in the Valencian community by means of otolith morphometryand microchemistry. Specimens (total length: 250?350 mm) were obtained fromOctober 2011 to March 2012 with gill nets in two protected wetlands: the ParqueNartural de l?Albufera de Valencia (AV) (n = 45), a Mediterranean lake; and the ParqueNatural Salinas de Santa Pola (SP) (n = 37), a coastal salt marsh. Otolith shape indices(circularity, rectangularity, aspect ratio, surface occupied by sulcus, ellipticity and formfactor) and microchemistry (Sr/Ca and Ba/Ca ratios) were measured and compared asarea markers. The chemical composition of the water in both areas was also obtained.Morphometric results showed, by an ANOVA with Bonferroni contrasts, that saccularotoliths from AV individuals had more edge complexity, hence a higher circularityindex (p < .001), but that there was less otolith percentage occupied by the sulcus(p < .001). When analyzing the morphometric variables simultaneously, both sites differedsignificantly (Hotelling?s T2 < 0.001). A paired t-testamong sites of the microchemicalvariables showed that otoliths of AV presented higher values of Ba/Ca ratiosand lower Sr/Ca ratios (p < .001). This coincides with water values obtained and couldbe associated with the low salinity observed in the lake. The opposite pattern wasobserved in SP, both for otolith and water samples, this being associated with thehigh-salinity waters of the area. Results obtained in the present research suggest, bythe use of otolith morphometry and microchemistry, that the nursery grounds of juvenileM. cephalus in the Valencian community could be differentiated. Even thoughhabitats could be separated using otolith morphometry, only a few of the studiedshape indices were important in area differentiation. Nevertheless, the use of bothmethodologies simultaneously could be robust habitat markers for this species.