In some capsules, the whelks that had developed into normal size,
similar to that of other live hatchlings, died. This occurrence may be
the result of static hatching mode, in which the capsule wall would
be thinned during hatching by the action of proteolytic substances
(Hawkins and Hutchinson, 1988). Under natural conditions, sea
water movement can help in tearing off the mucus plug sealing the
apex of the capsule, thereby allowing the hatchlings to climb out.
However, in artificial breeding conditions, no such external force is
exerted; the delay may have caused the death of the whelks. Once
any cleft is found at the top region, the capsule should be cut to
allow the hatchlings to come out and thus prevent mortality.