Vessel Impacts
Hawaiian Islands Humpback Whale

Ship strike scars on whale
Marine mammals and other marine organisms can be impacted by vessel strike, which may lead to injury or death in animals. Credit: NOAA, HIHWNMS.

Why is it a concern?

Tourist dolphin watching
Wildlife approach and interaction can lead to behavioral harassment or physical injury. For example, swimmers and vessels have been documented harassing spinner dolphins in bays in Hawaii while dolphins are attempting to rest during the day. Credit: Barbara Billand.

Visitors, scientists, fishermen, commercial shippers, and other stakeholders of the Hawaiian Islands Humpback Whale National Marine Sanctuary (HIHWNMS) access the sanctuary through the use of recreational and commercial vessels. These vessels are an important part of the “blue economy” and also provide a safe way for many visitors to experience some of the sanctuaries most iconic places. However, there are several impacts from vessels that can impact biological and archaeological resources within the sanctuary. These impacts include ship strikes, ship groundings, lost containers from shipping vessels, and discharge of waste water and other materials from ships.

As the population of Hawai’i increases, dependence on ocean transportation is expected to increase. About 80 percent of food and merchandise is imported to Hawai’i, of which 98 percent arrives by ship to commercial harbors around the state. Heavy vessel traffic increases opportunities for collision with humpback whales and other marine mammals which can lead to serious injury or death. Most lethal or severe ship strike injuries to large whales are caused by ships 80 meters or longer and travelling 14 knots or faster. Mitigation measures such as: observation with visual, radar, sonar and infrared technologies as well as a reduction of speed in high-density whale areas, may reduce the likelihood of collision.

The operation of commercial and recreational thrill-craft (e.g., water sledding, parasailing vessels and high speed motor craft) may also adversely affect marine mammals and turtles in Hawaiian waters. Small, fast and highly maneuverable, these crafts increase the risk of collision between marine species and vessels. Their small size increases the risk of injury to vessel operators and passengers, while their high speed reduces the time for the animals and operators to detect and avoid collision. The state of Hawai’i prohibits parasailing and certain other boating activities in areas off the western and southern shores of Maui during the humpback whale breeding season. However, thrill-craft continue to operate in other Hawaiian waters where humpback whales are found.

Coral reefs are also vulnerable to impacts from vessels and can be damaged by improper anchoring and from ship groundings.

Anchor Coral
Corals are fragile and can be damaged by improper anchoring as well as ship groundings. Credit: Jon Martinez, HIHWNMS, NOAA.

Overview of Research

Project Name PI and contacts Links

Historical Evidence of Whale/Vessel Collisions in Hawaiian Waters (1975 – Present)

Dr. Marc Lammers

Sub-surface and night-time behavior of Humpback whales off maui, hawaii:

A preliminary report

Robin Baird


Science Needs and Questions

  • How do whales use the water column and how can this information inform policies to mitigate collisions between whales and shipping?
  • How do whales react to the approach of vessels and how can this information inform policies to mitigate collisions between whales and shipping?
  • How much diel, annual and inter-annual variability exists in the underwater behavior of endangered whales and how can this information inform policies to mitigate the risk of ship strikes to whales?

Education and Outreach Material

The sanctuary hosts a variety of free educational programs and classes and activities, some of which are related to the issue of vessel impacts. A tip sheet for avoiding vessel collisions has also been developed.


Baird, Robin W., Allan D. Ligon, and Sascha K. Hooker. "Sub-surface and night-time behavior of humpback whales off Maui, Hawaii: a preliminary report."Report prepared under Contract 40ABNC050729 (2000).

Herman, L.M., K.J.C. Goetschius, E.Y.K. Herman. 2003. Threats to humpback whales in Hawaiian waters. Part C: A summary of military activities in sanctuary waters, Shallow water training ranges. Report to the Hawaiian Islands Humpback Whale National Marine Sanctuary. Honolulu

Laist, D. W., A. R. Knowlton, J. G. Mead, A. S. Collet, and M. Podesta. 2001. Collisions between ships and whales. Marine Mammal Science 17(1):35-75.

Lammers, Marc O., Adam A. Pack, and Lisa Davis. Historical evidence of whale/vessel collisions in Hawaiian waters (1975–present). OSI Technical Report 2003-01. Prepared for the Hawaiian Islands Humpback Whale National Marine Sanctuary. Oceanwide Science Institute, Honolulu, HI, 2003.

US Department of Commerce. National Oceanic and Atmospheric Adminstration. 2003. Workshop report on management needs to minimize vessel collisions with whales in the Hawaiian Islands Humpback Whale National Marine Sanctuary and other National Marine Sanctuaries.