Dissolved Oxygen Requirements for Embryonic and Larval Development of the Hardshell Clam, <i>Mercenaria mercenaria</i>

Abstract

Eggs and larvae of Mercenaria mercenaria were exposed to various levels of dissolved oxygen for varying time periods. Larval growth was normal in levels of dissolved oxygen at or above 4.2 mg/liter, but was essentially curtailed in levels at or below 2.4 mg/liter. Larvae survived extended exposures of 1 mg/liter, but showed little growth. Growth rates of larvae transferred to conditions of high dissolved oxygen after various periods of exposure to low dissolved oxygen became normal. Eggs developed normally at oxygen levels down to 0.5 mg/liter. One hundred percent mortality was experienced at 0.2 mg/liter.