Settlement and growth of eastern oysters produced from cryopreserved larvae

Document Type

Article

Publication Date

9-1-1998

Abstract

Previous reports on viability of cryopreserved oyster larvae have been limited to evaluation of planktonic stages for less than 6 d after thawing. However, for hatchery and aquacultural purposes the performance of larvae through settlement is of primary importance. The present experiments on production of oysters from cryopreserved larvae were conducted in two consecutive years. Observations through veliger larvae only were collected from the first year because of interruption by a hurricane. In the second year, growth was observed for 4 months. A total of 3 x 106 trochophore larvae (12 h post-fertilization) were diluted in a cryoprotectant solution composed of artificial sea water and 15% propylene glycol. Larvae were placed in 5-mL straws, frozen at -2.5 °C per min, and stored in liquid nitrogen. The frozen material was transported to an oyster hatchery at Grand Isle, Louisiana. Larvae were thawed at 70 °C for 15 sec and were incubated in a 200-L tank. For a control treatment, 6 x 106 eggs were fertilized and incubated in the same conditions as the thawed larvae. After 24 h of incubation, 28% of the control group developed into D-stage larvae, while 24% of the thawed larvae developed to this stage. Larvae were fed daily with 20 L of microalgae (Isocrysis galbana) for 10 d. After incubation, larvae were allowed to metamorphose and attach to substrate and were held for 8 d. Spat were placed in mesh plastic bags and suspended in Caminada Bay (29°15'12'N, 90°03'26'W) to evaluate survival and growth. After 4 months, 1,000 oysters from the control group, 850 from the thawed larvae, and 57 from naturally spawned oysters were found. The results indicate that oysters produced from thawed larvae developed normally in the hatchery, opening opportunities for use of cryopreserved larvae in oyster research and in commercial industry.

Publication Source (Journal or Book title)

Cryo-Letters

First Page

283

Last Page

292

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