Effects of temperature on early development of the New Zealand geoduckPanopea zelandica(Quoy & Gaimard, 1835)

Abstract

The New Zealand geoduck Panopea zelandica (Quoy & Gaimard, 1835) is a large, infaunal, sessile clam inhabiting subtidal areas around New Zealand. Geoduck population densities in New Zealand are estimated to be relatively low with patchy distributions, based on washed up shells on local beaches (Gribben, Helson, & Millar, 2004) and in situ accounts of other populations in Patterson Inlet, Stewart Island and throughout Golden Bay, Tasman (Breen, Gabriel, & Tyson, 1991;Powell, 1979). Ecological studies on known populations indicate that P. zelandica occurs mainly in shallow waters (5-25 m) in sandy and muddy habitats (Gribben et al., 2004). Annual bands in polished shells show that P. zelandica appear to live at least up to 85 years (Gribben & Creese, 2005). Gribben and Creese (2005) also inferred that P. zelandica appear to be functionally protandric and mature early (most within 2 years).From a commercial perspective, geoducks are highly prized in Asian markets. For example, a high quality individual of 8-16 cm shell length and a total weight of 300-800 g can fetch a price of $USD 220-330 kg −1 in China (Shamshak & King, 2015). Thus, the potential for cultivating P. zelandica has received considerable attention and is expected to add value and diversification for the New Zealand aquaculture industry (Alfaro, Jeffs, & King, 2014). To date, the New Zealand aquaculture sector has been focused on three main export species: Chinook salmon (Oncorhynchus tshawytscha), Pacific oyster (Crassostrea gigas) and Greenshell™ mussels (Perna canaliculus).

Carry-Over Effects of Broodstock Conditioning on the Salinity Tolerance of Embryos of the New Zealand Geoduck (Panopea zelandica)

“…Survival, which included embryos, trochophores, and Dveligers, was measured by counting the individuals that were visible, regardless of developmental stage and abnormalities, in each TCD well for each feeding ratio and salinity treatment. Different early development stages were identified by descriptions provided by Le et al [19] and by Sharma et al [15]. Survival percentages were calculated using the following formula: The D-veliger stage was chosen as an endpoint as it is a transition from a nonfeeding phase to a feeding larval state.…”

“…During development, embryos are more sensitive to environmental stressors compared to the juvenile and adult stages, especially with regard to salinity and temperature [13,14]. Indeed, even minor deviations from optimal temperature ranges have been known to cause reduced developmental rates and increased abnormalities of embryos and larvae of P. zelandica [15]. As for salinity, pacific geoduck (P. japonica) embryos were shown to have a low salinity tolerance with both embryos and larvae unable to survive at salinities below 26 ppt [16].…”