OUR OCEAN, OUR OBLIGATION, OUR OPPORTUNITY: GUIDANCE FOR REDUCING THE NUMBER OF WHALE STRIKES

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Published: 10 July 2025

Last month we celebrated “World Oceans Day” and the “United Nations Ocean Conference”, and this year the IMO has made their World Maritime Day theme “Our Ocean, Our Obligation, Our Opportunity”, so it is particularly relevant to discuss how shipping can better protect marine species.

Whilst exact numbers are impossible to define, it is estimated that hundreds of whales are injured or killed each year after being struck by ships.

For some species of whale, such as the endangered North Atlantic Right Whale – of which only approximately 370 remain – human interactions such as ship strikes threaten the survival of the species.

There are many reasons for the high frequency of ship strike, but the most common are:

• The whales’ migratory paths and habitats coinciding with main shipping routes
• Whales are comparatively slow moving and may find it difficult to move clear of an approaching ship quickly enough
• Many whales rely upon their hearing to alert them of danger from shipping, but a combination of the overall noise from ships causing confusing and phenomena such as the ‘bow null effect’ may prevent whales from identifying any threat
• Whales are very difficult to detect in darkness and even in daylight, their dark colour can make it difficult to identify their presence quickly enough for a ship to avoid them
• Whales can spend significant periods of time either at or close to the surface, increasing their vulnerability to ship strike

The International Maritime Organization (IMO) recognising this seriousness of the problem issued guidance¹ (MEPC.1/Circ.674) in 2009 to assist member governments in establishing systems to reduce the frequency of whale strikes.

The guidance establishes that maritime safety is of paramount concern, and that any action taken by coastal states should consider the potentially adverse impacts on the shipping industry.  It is therefore clearly recommended that any controls are only implemented after assessing and analysing the available scientific research and data. Furthermore, any adopted measures should be restricted to the minimum time and geographical area necessary.

It is generally agreed that the safest approach is to keep whales and shipping apart, and where that is not possible, the next best option is for ships to reduce their speed in areas where whales are known to be present.

Coastal states have approached the problem in several ways, with a mixture of mandatory and voluntary controls. Unsurprisingly, experience has shown that the mandatory controls are complied with much more often than voluntary measures.

IMO Ships routeing measures have been established where practicable to avoid the highest concentration of whales and Particularly Sensitive Sea Area (PSSA)’s can also include measures to reduce whale strikes.

Some regions, such as in the waters of the State of California, have increased public knowledge of the benefits of ships voluntarily reducing speed, linking the issues of whale strikes with underwater noise and air pollution. The shipping companies that take part are fully recognised for their work in this field with details available on the Blue Whales Blue Skies website².

The World Shipping Council (WSC) have produced the ‘WSC Whale Chart³’ that consolidates many of the publicly known controls into a single document. The currently available Second Edition was published in October 2024, and WSC intend to issue an update annually. We recommend that this is consulted as part of the voyage planning process, to provide a quick overview of areas that may have whale strike protection rules.

In a related measure the IMO, produced revised guidelines⁴ (MEPC.1/Circ.906/Rev.1) on reducing Underwater Radiated Noise (URN) from shipping, in November 2024.  Noting the adverse impacts that URN has on sea life in general, these guidelines present measures that can be followed by all stakeholders, for example, shipowners, ship designers, classification societies, and maritime authorities to assist in reducing URN. Whilst this primarily concerns new build ships, there are measures that can be taken by existing ships, such as following ship routeing measures, reducing propeller RPM, and optimising maintenance of machinery.

The following recommended practices are amongst those that may be followed to help reduce the risk of whale strikes:

• When voyage planning, check if the ship will pass through any areas where whales may be expected. Along with the previously mentioned ‘Whale Chart’ other resources, such as sailing directions and ships routeing measures should be consulted
• Where possible, avoid areas known to have high concentrations of whales during the time the ship is intending to transit that area
• Never approach a whale or group of whales deliberately
• Reduce speed where mandatory, and in voluntary areas where possible to safely do so
• Reporting schemes should be followed where offered, such as the ‘USCG WHALESNORTH’ system for those ships navigating in the Northeast USA. Participating in reporting schemes will allow ships to be contacted with the latest information on whale positions
• Obtain as much information as possible on the current location of whales, such as monitoring navigation warnings and resources such as whale spotting apps
• Report whale sightings promptly to relevant authorities or monitoring programs. Many areas also request reports to be made of any injured, distressed or dead whales.

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