Movement of hapuku (Polyprion oxygeneios) determined from tagging studies

Abstract

Hapuku (Polyprion oxygeneios) were tagged in south‐east South Island (SESI), Cook Strait (CS), and Poor Knights Islands (PKI), New Zealand, to determine their movements. 1623 fish were tagged and the overall recapture rate was 16.3%. Some hapuku were recaptured from the tagging sites (SESI 13%, CS 39%, PKI 40%), often after long periods at liberty, whereas others travelled substantial distances. The greatest distance travelled was 1389 km (by two fish) and the maximum period at liberty was 10.2 years. SESI hapuku tended to migrate northwards towards CS. The median distance travelled increased with hapuku length at recapture, suggesting that maturation and spawning stimulate migration. However, some of the smaller, immature hapuku also travelled several hundred kilometres. CS hapuku appeared to travel much shorter distances than SESI hapuku, but this may have been an artifact of the lower hapuku fishing effort outside the CS‐Kaikoura region. PKI hapuku showed very limited movements, and no interaction with CS or SESI fish. The results are consistent with the presence of a single stock in the SESI‐CS region, and possibly a separate stock in northern New Zealand.