Application of otolith mass and shape for discriminating scabbardfishes Aphanopus spp. in the north‐eastern Atlantic Ocean

Abstract

The otolith was used to investigate the variability between Aphanopus carbo and Aphanopus intermedius inhabiting the north-eastern Atlantic Ocean. The results indicate a high degree of morphological affinity between species and areas; a noticeable metabolic change in the otolith shape was noted in the specimens of A. carbo, which may be related to migrations of individuals from shallow water (closer to the continental coast) to deeper water (archipelagos of Madeira and the Canary Islands). The results suggest a single population for both species in the north-eastern Atlantic Ocean, although not conclusively.

Otolith Sr:Ca ratio and morphometry as indicators of habitat of a euryhaline species: The case of the silverside Odontesthes bonariensis

“…Other approaches such as the analysis of otolith morphology and morphometry have been widely used to differentiate fish stocks (Longmore 2010, Cañás et al 2012, Keating et al 2014, and even to identify existing species (Tuset et al 2013, Zhuang et al 2014 or fossilized fish (Reichenbacher et al 2009, Reichenbacher andReichard 2014); however, only a few studies relate morphometric variables to different environments or ecomorphological patterns (Nelson et al 1994;Volpedo and Fuchs 2010;Avigliano et al 2012Avigliano et al , 2014.…”

“…El análisis de la morfometría de los otolitos permite generar una descripción cuantitativa de la forma y el contorno que puede compararse estadísticamente (Lestrel 1997). Entre los índices morfométricos más utilizados están la circularidad, rectangularidad, elipticidad, factor de forma y área del sulcus/área del otolito (e.g., Volpedo et al 2008, Longmore et al 2010, Cañás et al 2012, Tuset et al 2013. De hecho, ambas metodologías se han usado conjuntamente en estudios recientes (e.g., Longmore et al 2010.…”

“…Posteriormente, se calcularon los siguientes índices de forma: circularidad (PO 2 /AO), rectangularidad (SO/[LO × AO]), elipticidad (LO -AO/LO + AO), factor de forma ([4π × SO/PO 2 ]) y SS/SO. La nomenclatura de los índices utilizados fue tomada de Tuset et al (2013) y Volpedo et al (2008). La circularidad da información acerca de la complejidad del contorno de los otolitos (Tuset et al 2003).…”

“…The following shape indices were then calculated: circularity (OP 2 /OW), rectangularity (OA/[OL × OW]), ellipticity (OL -OW/OL + OW), form factor ([4π × OA/OP 2 ]), and SA/OA. The nomenclature of the indices used was taken from Tuset et al (2013) and Volpedo et al (2008). Circularity provides information on the complexity of the otolith contour (Tuset et al 2003).…”

“…The morphometric analysis of otoliths permits a quantitative description of the shape and contour that can be statistically compared (Lestrel 1997). Some of the most commonly used shape indices are circularity, rectangularity, ellipticity, form factor, and sulcus area/otolith area (e.g., Volpedo et al 2008, Longmore et al 2010, Cañás et al 2012, Tuset et al 2013. In recent studies, both methods have been used (e.g., Longmore et al 2010.…”