Managing around oyster disease: Using hatchery-produced oyster spatfor restoration efforts

摘要

Oyster diseases have devastated the natural populations of oysters in Chesapeake Bay. Mean densities on most oyster bars are less than 2/m2. The annual harvest has hit record lows the last 2 years. The use of natural seed has become limiting for several reasons. First, spatsets have occurred infrequently and in relatively low abundances in the last several years. Second, natural spat quickly acquire Perkinsus marinus infections (Dermo) and movement of infected oysters spreads the disease. Hatchery-produced spat offer advantages in restoration, including the ability to plant at high densities (250-500/m super(2)) and to use specific-pathogen free (SPF) oyster spat. Therefore, using hatchery-produced SPF seed offers the opportunity to conduct large-scale, benthic field experiments to better understand oyster growth and mortality, disease acquisition, and the ecologic aspects of oyster reef formation. To date, studies have shown that hatchery-produced oysters planted on the Bay bottom grow quickly and have a relatively low natural mortality rate (10% annually, excluding MSX or Dermo-related deaths) and that many populations planted in mesohaline waters acquire relatively low levels of Dermo infection. Reserve studies are currently underway to determine the potential of hatchery-produced oysters in large-scale production.