Expert Report

Each report is produced by a committee of experts selected by the Academy to address a particular statement of task and is subject to a rigorous, independent peer review; while the reports represent views of the committee, they also are endorsed by the Academy. Learn more on our expert consensus reports.

With seafood consumption rising and wild stocks of marine life decreasing, mariculture -- the cultivation of marine organisms in their natural environments -- is becoming an increasingly important source of bivalve shellfish such as oysters, mussels, and clams. However, mariculture operations can affect the integrity of natural ecosystems where they are located, for example, by disturbing marine flora that provide habitat for fish and invertebrates. Expanding mariculture operations will require the adoption of best management practices or performance standards to limit undesirable consequences. Analysis suggests performance standards that monitor key indicators of ecosystem health are most effective, because the scale, location, and type of mariculture operation can be taken into account.

Key Messages

  • Although best management practices are useful in some circumstances, performance standards that monitor key indicators of ecosystem health are most effective because the scale, location, and type of mariculture operation can be taken into account.
  • Bivalve shellfish feed by filtering food from seawater, and excrete organic waste, impacting the physical and chemical environment, modifying habitats, and affecting the food web and biogeochemical cycling; but the extent of these impacts varies with environment, location, and species of shellfish.
  • Diseases that occur at low levels in wild populations can flourish in mariculture facilities, due to altered conditions like crowding and temperature fluctuations.
  • Historically, several bivalve species have reproduced and established self-sustaining populations outside the mariculture facility, they can also carry unintended "hitchhiker" species, such as algae, that can thrive and spread once introduced to a new environment
  • The equipment used to hold and protect shellfish during growth provides surfaces for small marine organisms to attach, attracting the fish and crustaceans that feed on them; potential negative impacts include the entanglement and drowning of birds, marine mammals, and marine turtles in nets.
  • The full impact of mariculture operations on an ecosystem may not be fully understood until scientists have better indicators of the carrying capacity of an ecosystem