ABSTRACT
Crassostrea virginica (formerly the “American oyster”) was designated in 1985 as the “eastern oyster” by the Committee on Scientific and Vernacular Names of Mollusks of the Council of Systematic Malacologists [1]. The eastern oyster is a lamellibranch with pronounced bilateral asymmetry [2] and usually spawns as a male in the first year, a condition called protandry. Fecundity has been estimated to be between 500,000 and 66 million eggs per female depending upon body size [3,4]. Within 8 to 12 h (depending on temperature) fertilized eggs develop into freeswimming larvae or trochophores (50 to 60 μm in width). After ∼24 h, the trochophore larvae develop into veliger or D-stage larvae (70 to 125 μm). After metamorphosis, the settled larvae develop into adults within 1 to 2 years. Adult oysters mature and spawn in the summer months (April to September in the Gulf of Mexico) for the next cycle [5,6]. The eastern oyster is the most important bivalve species in the United States [7]. However, along the Atlantic and Gulf coasts, oyster production has declined over the past century due to reasons including a lack of consistent seed supply, excessive harvest, loss of suitable habitat, disease, and natural predation [8]. The use of cryopreserved gametes and larvae can improve hatchery production of seedstock to increase production for the oyster industry. Cryopreservation of oyster sperm and larvae has been tested at the laboratory level, but given the benefit that this technique offers, cryopreservation of oyster sperm and larvae should be developed for commercial application at the hatchery level. The procedures outlined below are suitable for application at the hatchery scale, and could be scaled up for commercial application.
