Length-weight relations for seven grenadier species (Actinopterygii: Gadiformes: Macrouridae) to the west of Ireland

Abstract

Length-weight regressions for seven grenadier species: Coryphaenoides rupestris Gunnerus, 1765, Trachyrincus murrayi Günther, 1887, Coelorinchus caelorhincus (Risso, 1810), Nezumia aequalis (Günther, 1878), Coryphaenoides mediterraneus (Giglioli, 1893), Coelorinchus labiatus (Köhler, 1896), and Coryphaenoides guentheri (Vaillant, 1888) are calculated from data collected on a series of deepwater surveys conducted by the Irish Marine Institute from 2006 to 2009, on the continental slope to the west and northwest of Ireland and the northern slope of the Porcupine Bank. The regression calculated for roundnose grenadier, C. rupestris, is compared with other regressions calculated for the species from different areas of its north Atlantic range. The difficulties associated with measuring many grenadier species, due to the fragility of their tails, are discussed. A recommendation is made that pre-anal fin length should be accepted as the standard.