Preliminary estimates of age, mortality, growth, and reproduction in the hiatellid clam Panopea zelandica in New Zealand

Abstract

Samples of the hiatellid clam Panopea zelandica were taken from commercial catches near Nelson, New Zealand, where a new fishery developed in 1988. Ages were estimated by counting internal growth rings seen on acetate peels taken from polished and etched sections of the umbo region. Although the estimated ages are not validated, they are based on a validated technique for a similar species in North America, and they provide a preliminary examination of growth and mortality characteristics of this species. Maximum ring count was 34. Growth in shell length appeared rapid to age 10, then slowed. Natural mortality rate appeared to be around 0.20. All individuals examined in a sample taken in March appeared to have spawned recently and were in the redeveloping stages of gametogenesis. Sex ratio was not significantly different from 1:1. © Crown copyright 1991.