However, observational methods are non-destructive and allow information from
one identical object to be gathered over time. This approach has long been common
in rocky shore ecology where researchers can reach their study sites without getting
wet and can document their observations directly in situ. While sample material
is rarely removed, visual impressions are recorded. Other non-destructive methods
include the observation of invertebrate behaviour in aquaria. Image recording in
both these situations can be undertaken with non-specialist camera systems. However,
when imaging devices are taken into an underwater environment, specialist
systems and carriers must be deployed.