It is an offence to intentionally or recklessly disturb a cetacean or basking shark, and ignorance of the law is no defence. All club members and instructors should be aware of what disturbance is and how to prevent it. Legislation also exists to protect certain species and habitats from damage and disturbance. All dolphins, porpoises and whales, basking sharks, marine turtles and birds are protected by law against intentional killing, injuring and taking.
So what constitutes disturbance and why is it so damaging? Disturbance can be caused by noise, wash or by just being too close. Disturbance simply means affecting the way in which animals would normally behave and it can have a detrimental effect on their behaviour, breeding, feeding, resting and ultimately their numbers.
For example, a flock of seabirds rafting up to rest at sea may take off as they are disturbed by a passing boat. This, in itself, may not seem like too much of a problem, but if repeated as boat after boat goes by, then the important resting period would be constantly disturbed. This would lead to increased energy consumption, stress and the need for more food.
Other examples include: engine noise interfering with the acoustic communications of whales and dolphins, affecting the way they hunt for prey. Speeding vessels can also affect the reproductive cycles of fish and excess wash can cause bank erosion and the loss of habitats.