The majority of all coral species (70%) is hermaphroditic
and releases egg–sperm bundles–these bundles are usually
positively buoyant and float to the water surface where fertilization occurs within half an hour. The egg–sperm bundles can be relatively easily collected on the reef using coneshaped tents with a sample bottle on top in which the bundles get trapped (Fig. 4). A few minutes prior to spawning,
these tents are placed above the coral. A much more comfortable, although more invasive, way to collect gametes
from broadcast spawners is the transfer of the donor colonies to culture tanks a few days prior to spawning. At the
spawning night, the colonies can be temporarily transferred
from the flow-through holding tanks to containers with
standing water; released gametes can be skimmed off the
surface using plastic pipettes or small cups –this must be