Collisions between vessels and
The movement of ships and boats
to and from ports may potentially have some effect
on marine life simply by virtue of their presence.
This is particularly the case with high-speed leisure
craft and in marine SACs designated for their marine
mammals. There have been a number of studies on
the effects of vessel movement on marine mammals.
These include the Institute of Zoologys Marine
Mammal Strandings Project (Jepson personal communication
1998), the Natural History Museums stranded
whale recording scheme (Muir personal communication
1998), the work of the Sea Mammal Research Unit
and Durlston Country Park in Dorset (Browning personal
communication 1998) and studies undertaken in Cardigan
Bay (Evans personal communication 1998) and the
Firth of Forth (Reid personal communication 1998).
Research has shown that although a rare occurrence
in UK waters, collisions do occur between marine
mammals and ships/boats operating at speed, which
may result in fatal injuries or wounding. However,
quantified information on the occurrence of these
incidents is very limited.
Over the past few years, there have been a limited
number of incidents where dead and stranded marine
mammals, often harbour porpoises, have shown evidence
of propeller damage or massive trauma, indicative
of ship collisions. In Scottish waters there have
been recent reports of fatal collisions between
vessels and basking sharks, which are a protected
species under the Wildlife and Countryside Act.
Further collision incidents are known to taken place
with seals, however, there is very little information
available on the occurrence of these events (National
Seal Sanctuary personal communication 1998). Generally,
the risk of collisions with marine mammals is greater
for recreational craft and dolphin-watching boats
and guidelines have been developed for minimising
the disturbance to dolphins and porpoises from these
As one would expect, wherever possible, animals
will avoid contact with moving vessels. However
this is not always the case, for example dolphins
and porpoises often actively seek out moving vessels
and swim close alongside in the bow wave which may
make them vulnerable to injury from collision (A.
Muir Natural History Museum personal communication
1998). Many mariners, including yachtsmen, regularly
report the enthusiasm with which dolphins accompany
their vessels, often for relatively long periods
of time before diving away. For example, bottlenose
dolphins in the Moray Firth readily approach vessels,
to bow ride or to accompany them through the narrows
(UK CEED 1993).
Research has been undertaken by the Sea Mammal
Research Unit to establish the distribution of seals
around UK waters. Observations show that seals co-exist
with shipping in many areas around the coast. The
presence of fishing vessels may even provide an
additional food source as a result of the practice
of discarding unwanted fish overboard. It is unlikely
that other marine animals will be affected greatly
by vessel movements in the UK.