Length-weight relationship of four deep-sea chondrichthyans (Elasmobranchii & Holocephali) in Ecuadorian oceanic waters

Abstract

The present work reported the length-weight relationship of four deep-sea chondrichthyan species (i.e., Hydrolagus spp., E. granulosus, C. owstonii and C. squamosus) captured by the experimental fishery of the depth cod (Dissostichus eleginoides) in Ecuadorian oceanic waters, from 2018 to 2020. The fishing included 592 hauls, starting at 1,000 m depth, using between 1,000 to 1,500 N° 14/0 circle hooks. Length-weight relationship (LWR) was estimated by the power model (y = ax^b). The determination coefficient (r²) value was always above 0.94. The slope (b) showed negative allometric growth (b < 3) for females of C. owstonii, C. squamosus and males of E. granulosus and Hydrolagus spp. Allometry was positive (b > 3) in females of E. granulosus and Hydrolagus spp. as well as, in males of C. owstonii and C squamosus. In addition, the allometry for the combined sexes was negative in C. owstonii and was positive in C. squamosus and E. granulosus.