Length-weight and otolith size to standard length relationships in 12 species of Southern Ocean Myctophidae: A tool for predator diet studies

Fish morphometric relationships are key tools for fisheries science and studies of food web dynamics and predator foraging behaviour, but parameterisations are limited for Southern Ocean myctophids (Family Myctophidae). New standard length (L-S) to total mass (M-T) relationships are therefore described for the 12 biomass-dominant myctophid fish species living in the Scotia Sea, Southern Ocean, using the most comprehensive data collected in the region to date. New linear regressions for otolith size (length; O-L and width; O-W) and L-S are also described. Significant (p < .01) L-S-M-T relationships were established for all species using simple non-linear regression. Significant (p < .01) relationships between L-S and both O-L and O-W were also determined for all species, with O-W being the best predictor of L-S in all but one species. Our study provides a comprehensive tool for reconstructing the myctophid component of marine predator diets that will improve future food web, predator behaviour and ecosystem studies in the Scotia Sea.