Boating with Whales – What Depth?

Image taken under NOAA Fisheries Research Permit 21321

Research in Hawai`i has found that humpback whales are most frequently found in waters with a depth of 100 fathoms or less (Mobley & Herman, 1999), as seen in the estimated density for humpback whales throughout the main Hawaiian Islands below.

During whale season if you are transiting waters at depths of 100 fathoms or less, you have a higher chance of encountering and colliding with a whale, which may kill or severely injure the animal, and/or cause damage or sink a vessel, and injure passengers aboard your vessel.

Take these preventive measures to reduce your chances of a collision:

  • Vessels should travel at a speed of 15 knots or less, or at minimal planning speed, when in depths of 100 fathoms or less during the humpback whale season.
  • Tour operators should reduce speed to six knots or less within 400 yards when approaching or departing humpback whales.
  • Vessels should post a dedicated lookout to help spot whales.
  • It is illegal to leap-frog ahead or cut in front of a whale’s path.

 

an image showing the recommendations of safe boating practices from the main whale page.

 

 

1. What TIME of Year?

2. What DEPTH?

3. What SPEED?

4. What DISTANCE?

5. What’s the SOLUTION?

 

Return to Boating with Whales start page

(LAST UPDATED 7/23/25.)