Dolphins, porpoises and whales

Porpoises, whales and dolphins can be seen from the coast or at sea around Cornwall. Dolphins (particularly bottlenose dolphins) and porpoises can often be seen feeding and socialising close to shore all year round. Minke and fin whales occasionally come in closer to shore, particularly in deeper water areas and long-finned pilot whales can often be seen with dolphins or minke whales.

Actions that scare, startle or panic:

  • Getting too close
  • Approaching animals head on
  • Sudden changes in speed, direction, or engine noise
  • Surrounding or boxing them into an area
  • Using an echo sounder or fish finder near to porpoises or dolphins

How to tell you’ve been spotted:

  • Sudden and erratic movements (although these could be associated with feeding or play)
  • Bunching together
  • Changes in diving behaviour and less frequent surfacing
  • Changes in breathing patterns
  • Increased vocalisation (you’ll only be able to hear this if you’re using a hydrophone)

It’s too late and definitely time to move away if:

  • They increase their swimming or travelling speed
  • Females maneuver to shield their calves
  • They slap their tail or head on the water surface
  • They become aggressive towards watchers or each

Tips to avoid disturbing porpoises, dolphins and whales
Follow the general guidelines and in particular:

  • Keep clear of large groups and mothers with young
  • Ensure all encounters are on their terms by, ideally, only being close to them if they choose to be close to you – e.g. dolphins bow-riding
  • If you find yourself unexpectedly close, slow down or stop and allow them to pass. Put the engine into neutral so there is no chance of injuring them with the propeller and check carefully before re-engaging the engine
  • If dolphins choose to bow-ride, maintain a steady speed and course and stay vigilant
  • Don’t approach again once you or the animal have moved away
  • Make sure your engine and propellers are well maintained

If you do decide to approach:

  • From a minimum of 1km away, approach side on, at a steady slow speed (less than 6 knots) making sure they have a good clear escape route
  • Keep to the outside of a group of animals to avoid scattering or separating them and leave them plenty of space
  • Maintain a steady direction and ‘no wake’ speed
  • Limit the time you spend with them, leave after 15 minutes
  • Limit the number of boats in proximity to the animals by leaving the area is necessary

How disturbance affects them:

  • Interacting with or avoiding humans can disrupt their communication and use up vital energy, making animals more prone to disease and attack from predators
  • Whales, porpoises and dolphins use echo-location to interpret their environment and find out where other animals and objects are. Engine and propeller noise can confuse or drown out these sound signals which can disorientate the animals and disrupt their communication and feeding
  • Whales, dolphins and porpoises can be injured or killed in collisions with boats and propellers.
MAIN PHOTO: copyright Niki Clear