Stock discrimination of hoki (Macruronus novaezelandiae, Merlucciidae) in New Zealand waters using morphometrics

Abstract

Abstract We compared morphometric features of adult‐size (75–95 cm total length) hoki, Macruronus novaezelandiae, from the two main spawning grounds (West Coast South Island, Cook Strait) and from the two main areas of dispersal (Auckland Island‐Campbell Plateau, Chatham Rise) to determine if more than one stock is evident. Significant differences (P > 0.001) in head shape were found between the two spawning grounds and between the dispersed areas. When sample sets from the four areas were combined, West Coast and Cook Strait spawning samples were the least similar. Auckland Island‐Campbell Plateau stock morphometrics were closest to West Coast, while those of Chatham Rise were closest to Cook Strait's. The data provide strong evidence that Cook Strait and West Coast spawners are from different stocks. There is also some support for the hypothesis that Auckland Island‐Campbell Plateau hoki are from the same stock as the West Coast spawners, and that Chatham Rise hoki are from the same stock as the Cook St...