Publications: Peer-reviewed journal articles (by staff)

Functional morphology and performance of New Zealand geoduck clam (Panopea zelandica) larvae reared in a flow-through system

1 February, 2017
CITATION

Le DV, Alfaro AC, Ragg NLC, Hilton Z, Watts E, King N 2017d. Functional morphology and performance of New Zealand geoduck clam (Panopea zelandica) larvae reared in a flow-through system. Aquaculture 468, Part 1: 32-44.

DOI link here

ABSTRACT

Understanding the parameters required for a reliable hatchery seed production of the endemic geoduck clam Panopea zelandica (Quoy and Gaimard, 1835) is crucial if New Zealand is to develop a geoduck aquaculture industry. To provide the foundation for routine geoduck larval rearing practices, this study reports on physiological, morphological, and behavioral characteristics throughout the larval developmental process. P. zelandica larvae were reared at 17 °C and 35 ppt, and fed continuously with Tisochrysis lutea and Chaetoceros calcitrans in a flow-through system. The initial veliger stocking densities ranged from 50 to 200 larvae mL− 1, while residual algal levels were maintained at 20,000 to 80,000 cells mL− 1 in three rearing batches. Larval behavior and morphology were described through observation using video recordings, photomicrographs and scanning electron microscopy. The larval development took 16–19 days from first D-veliger and metamorphosis occurred across a wide size range (300–375 μm shell length). The increase in shell length was linear over time and correlated with the deposition of striae in the prodissoconch II. The ingestion rate followed a power function with time and was closely correlated with the development of the alimentary system, including mouth, esophagus, stomach, style sac, intestine, and digestive gland. Rearing with an initial stocking density of 100 larvae mL− 1 and residual algal background of 20,000 cells mL− 1 resulted in about 76% survival and 15 μm d− 1 growth rate. The results of the preliminary production trials inform rearing practices and provide biological descriptions that appear to be effective as a baseline protocol for the successful commercial production of P. zelandica larvae.