| Summary: | Aquaculture in New Zealand is an important growing export industry and around 66 % of its total production is exported, which is worth NZ $ 400 million every year. Based on the growth strategy of this industry, the aim is to achieve an annual production of U.S $ 1 billion by 2025. In New Zealand, the Pacific oyster Crassostrea gigas, is a leading cultivated species with significant exports, along with King salmon and the New Zealand GreenshellTM mussel. Pacific oysters are native to Japan, but now are well established in many parts of the world including New Zealand. Most of the culturing for Pacific oyster in New Zealand is conducted using wild seed, the majority of which are gathered in the Kaipara Harbour on the north-western coast of the North Island. However, this source is highly unreliable, for example recent outbreaks of Ostreid herpesvirus-1 (OsHV-1) led to mass mortality of Pacific oyster larvae in 2010 leaving huge losses within this industry. To overcome these natural disasters and seasonal constraints, use of cryopreserved larvae has been suggested by many scientists. With this method of storing, larvae can be thawed to meet hatchery demands at any time. However, the degree of success using cryopreservation technique is highly variable due to lack of optimum protocols which are highly species specific. Furthermore, little is known about the freezing and cooling effects on the viability of larvae and their subsequent development. Previous studies have been focused on high survival rates just after post-thawing but recently the need to study the effect of cryopreservation on the larval quality over a longer time frame has been recognized. Before cryopreservation techniques can be applied to oyster larvae, a good understanding of the basic larval development process is necessary under normal conditions. There is lack of literature available on the detailed larval development under normal hatchery conditions for Pacific oysters. Therefore, the present study is the first to comprehensively describe the ...
|
|---|