Members Handbook 20023 - ITOPF

Effects of Marine Oil Spills
Oil spills can have serious effects on
marine life, as highlighted by the
photos of dead birds which immediately
appear in the news after any spill.
Such images fuel the perception
of widespread and permanent
environmental damage after every spill,
and an inevitable loss of marine
resources. A science-based appraisal of
the effects reveals that whilst damage
occurs and may be profound at the level
of individual organisms, populations are
more resilient and natural recovery
processes are capable of repairing the
damage and returning the system to
normal functions. The first stage on the
road to recovery is usually a well
conducted clean-up operation but in
some specific habitats aggressive cleanup
methods can cause more harm than
good and then it is better to let natural
cleaning processes take their course.
Many spill impacts have been
documented in the scientific and
technical literature, and although not
all the effects of oil pollution are
completely understood, an indication
of the likely scale and duration of
damage can usually be deduced from
the information available. However, it
can be difficult to present a balanced
view of the realities of spill effects,
given the often highly charged and
emotional nature of a spill and its
aftermath. The scientific community
can become polarised into opposing
camps with one side intent on
quantifying every aspect of damage,
and the other emphasising the capacity
of the environment to recover
naturally. The simple reality is that
sometimes significant damage occurs,
sometimes not and the aim of this
review is to draw together what
general information is known about
spill effects and their longevity.
The marine ecosystem is highly complex
and natural fluctuations in species
composition, abundance and distribution
are a basic feature of its normal
function. The extent of damage can
therefore be difficult to detect against
this background variability. Nevertheless,
the key to understanding
damage and its importance is whether
spill effects result in a downturn in
breeding success, productivity, diversity
and the overall functioning of the
system.
21