Larval development of the New Zealand geoduckPanopea zelandica(Bivalvia: Hiatellidae)

Abstract

The larval development of the New Zealand geoduck, Panopea zelandica, grown under culture conditions, was described through measurements of shell morphometry using video image analysis, photomicrographs, and scanning electron microscopy (SEM). Gametes were stripped from ripe broodstock and eggs fertilised with a dilute sperm solution. Developing larvae were maintained at 17 ± 1°C. Fertilised eggs developed into trochophores within 12 h and to D-stage larvae (105.3 µm shell length) within 24 h. Larvae spontaneously settled after c. 16 days at c. 247 µm shell length. Measurements of shell morphology, including total length, total height, hinge length, length of anterior end, and umbo length and height were adequate descriptors of larval development. SEM indicated that the provinculum of D-stage and developing veliger larvae lacked any teeth, although there was some development of a small lamelliform tooth on the hinge structure of newly settled post-larvae. Prominent spines common on dissoconch shells of other hiatellid clams were absent in newly settled post-larvae of P. zelandica. The data presented here are the first description of the larval development and larval biology of P. zelandica. The relative ease of spawning and rearing of P. zelandica suggests that the development of commercial hatchery technology for this species warrants further investigation.

Growth, Survival, and Feeding Rates for the GeoduckPanopea globosaDuring Larval Development

“…For example, Panopea zelandica showed a relatively short larval period (16 days) but slower growth rate (10 mm/day) than P. globosa (Gribben & Hay 2003). The Pacific geoduck Panopea generosa exhibited the slowest reported growth rate within the genus Panopea Gross growth rate and mean (%SE) shell length and width at metamorphosis, percent survival, and duration of the metamorphic period of five larval cohorts of Panopea globosa reared in the laboratory in 500-L conical tanks.…”

Early life cycle and effects of microalgal diets on larval development of the spiny rock-scallop, Spondylus limbatus (Sowerby II, 1847)

“…Description of the main characteristics of embryonic, larval and post-larval development of target species is important for investigating larval dispersion, settlement events, levels of recruitment, and growth rates of bivalves (Gribben and Hay, 2003;Soria et al, 2012), and to establish proper hatchery production protocols. Likewise, the identification of the appropriate algal species and/or their combinations to provide the essential nutrients is required for effective growth and survival for S. limbatus larvae.…”

Fertilization success of the New Zealand geoduck,Panopea zelandica: Effects of sperm concentration, gamete age and contact time

“…Functional protandric dioecy is a feature of the reproductive development of P. zelandica with the largest individuals being female (Gribben & Creese ). As with other geoduck species such as P. generosa (Goodwin ; Goodwin, Shaul & Budd ), the larvae of P. zelandica are relatively easy to culture (Gribben & Hay ). However, for P. zelandica understanding the fertilization kinetics is an important knowledge gap for hatchery production of New Zealand geoducks, as it is integral to maximizing the production of zygotes and the development of healthy viable larvae.…”