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.
